Answer: [tex]2.2326\times 10^{-3}[/tex] moles
Explanation:
We are given:
Moles of electron = 1 mole
According to mole concept:
1 mole of an atom contains [tex]6.022\times 10^{23}[/tex] number of particles.
We know that:
Charge on 1 electron = [tex]1.6\times 10^{-19}C[/tex]
Charge on 1 mole of electrons = [tex]1.6\times 10^{-19}\times 6.022\times 10^{23}=96500C[/tex]
The metal being plated has a +4 charge, thus the equation will be:
[tex]M^{4+}+4e^-\rightarrow M[/tex]
[tex]4\times 96500C[/tex] of electricity deposits = 1 mole of metal
Thus 861.8 C of electricity deposits =[tex]\frac{1}{4\times 96500}\times 861.8=2.2326\times 10^{-3}[/tex] moles of metal
Thus [tex]2.2326\times 10^{-3}[/tex] moles of metal should be plated
The number of moles of the metal deposited is 0.0022 moles of metal.
What is electroplating?The term electroplating refers to the use of one metal to cover the surface of another metal. Let the metal in question be M, the equation of the reaction is; M^4+(aq) + 4e -----> M(s).
1 mole of the metal is deposited by 4( 96,500) C
x moles will be deposited by 861.8 C
x = 1 mole * 861.8 C/ 4( 96,500) C
x = 0.0022 moles of metal
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A 24.00 mL sample of a solution of Pb(ClO3)2 was diluted with water to 52.00 mL. A 17.00 mL sample of the dilute solution was found to contain 0.220 M ClO3−(aq). What was the concentration of Pb(ClO3)2 in the original undiluted solution? 3.60 × 10−2 M 7.19 × 10−2 M 0.238 M 0.156 M 0.477 M
Answer:
0.238 M
Explanation:
A 17.00 mL sample of the dilute solution was found to contain 0.220 M ClO₃⁻(aq). The concentration is an intensive property, so the concentration in the 52.00 mL is also 0.220 M ClO₃⁻(aq). We can find the initial concentration of ClO₃⁻ using the dilution rule.
C₁.V₁ = C₂.V₂
C₁ × 24.00 mL = 0.220 M × 52.00 mL
C₁ = 0.477 M
The concentration of Pb(ClO₃)₂ is:
[tex]\frac{0.477molClO_{3}^{-} }{L} \times \frac{1molPb(ClO_{3})_{2}}{2molClO_{3}^{-}} =0.238M[/tex]
Classify each statement as true or false. Drag the appropriate items to their respective bins. View Available Hint(s) Reset Help The valence electrons of group 4A elements are in the 5s subshell. Period 3 elements have an inner electron configuration of [Ar). The highest principal quantum number of period 4 elements is 4 Period 5 elements have six 4p electrons Period 5 elements have an inner electron configuration of (Kr Group 8A elements have full outer principal s and p subshells. The valence electrons of group 3A elements are in an s and p subshell. The highest principal quantum number of period 4 elements is 5 False True Submit
Explanation:
1) The valence electrons of group 4A elements are in the 5s subshell.
The given statement is false .
The valence electrons of group 4A elements are in the ns and np subshell .Where n is equal to 1 to 7.
2) Period 3 elements have an inner electron configuration of [Ar].
The given statement is false .
The noble gas which comes before third period is neon.Period 3 elements have an inner electron configuration of [Ne].
3)The highest principal quantum number of period 4 elements is 4.
The given statement is true.
The period number of periodic table indicates the value of highest principal quantum number.
4) Period 5 elements have six 4p electrons.
The given statement is true.
This so because 4p subshell is filled before filling of shells of fifth shell. So, the 4p subshell will obviously have 6 electrons.
5) Period 5 elements have an inner electron configuration of (Kr).
The given statement is true.
The noble gas which comes before third period is krypton .
6) Group 8A elements have full outer principal s and p subshells.
The given statement is true.
This is because the the group mentioned in the statement if noble gases and noble gases are inert in nature due to fully filled electronic configurations.
7) The valence electrons of group 3A elements are in an s and p subshell.
The given statement is true.
The valence electrons of group 3A elements are in the ns and np subshell .Where n is equal to 1 to 7. there general electronic configuration is [tex]ns^2np^1[/tex].
8) The highest principal quantum number of period 4 elements is 5
The given statement is false.
The period number of periodic table indicates the value of highest principal quantum number.
The electron address in an atom can be given with the help of quantum mechanics. It helps to locate electrons with quantum numbers.
(1) The valence electrons of group 4A elements are in the 5s subshell.
The ns in group 4A can vary from 1 to 7. Thus the statement is false.
(2) Period 3 elements have an inner electron configuration of [Ar).
The nearest noble gas has been Neon, thus the inner electron configuration is of [Ne]. The statement is false.
(3) The highest principal quantum number of period 4 elements is 4.
The period number has been equal to the highest principal quantum number. Thus, the statement is true.
(4) Period 5 elements have six 4p electrons.
It has 5 subshells, and 4 subshells have been filled prior to 5s. Thus, the elements have a 4p orbital filled with 6 electrons. The statement is true.
(5) Period 5 elements have an inner electron configuration of (Kr).
The nearest noble gas has been Krypton, thus the inner electron configuration is of [Kr]. The statement is true.
(6) Group 8A elements have full outer principal s and p subshells.
Group 8A belongs to a noble gas. The subshells of noble gas are completely filled. The statement is true.
(7) The valence electrons of group 3A elements are in an s and p subshell.
The electrons of the 3A group have a general configuration [tex]\rm ns^2\;np^1[/tex]. The electrons are filled in s and p subshell. The statement is true.
(8) The highest principal quantum number of period 4 elements is 5.
The period number has been equal to the highest principal quantum number. Thus, the statement is false.
For more information about the quantum numbers, refer to the link:
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An automobile engine provides 527 Joules of work to push the pistons. In this process the internal energy changes by -2886 Joules. Calculate q for the engine. This represents the amount of heat that must be carried away by the cooling system. q = Joules
Answer: -2359 Joules
Explanation:
According to first law of thermodynamics:
[tex]\Delta E=q+w[/tex]
[tex]\Delta E[/tex]= Change in internal energy = -2886 J
q = heat absorbed or released = ?
w = work done or by the system
w = work done by the system=[tex]-P\Delta V[/tex] {Work is done by the system as the final volume is greater than initial volume and is negative}
w = -527 J
q = ?
[tex]-2886=q+(-527)[/tex]
[tex]q=-2359J[/tex] {Heat released by the system is negative}
Thus the amount of heat released by the system and carried away by the cooling system is -2359 Joules
According to first law of thermodynamics:
= Change in internal energy = -2886 J
q = heat absorbed or released = ?
w = work done or by the system
w = work done by the system= {Work is done by the system as the final volume is greater than initial volume and is negative}
w = -527 J
q = ?
{Heat released by the system is negative}
Thus the amount of heat released by the system and carried away by the cooling system is -2359 JoulesAnswer:
Explanation:
If 55.0 mL of ethanol (density=0.789g/mL)) initially at 9.0 ∘C is mixed with 55.0 mL of water (density=1.0g/mL) initially at 28.6 ∘C in an insulated beaker, and assuming that no heat is lost, what is the final temperature of the mixture?
The final temperature of the mixture is approximately [tex]\(-57.97^\circ\text{C}\)[/tex].
To find the final temperature of the mixture, we can use the principle of conservation of energy, assuming no heat is lost or gained in the process.
The heat gained by the cold substance (water) will be equal to the heat lost by the hot substance (ethanol).
The heat gained or lost [tex](\(Q\))[/tex] can be calculated using the equation:
[tex]\[ Q = mc\Delta T \][/tex]
where:
- [tex]\(m\)[/tex] is the mass of the substance,
- [tex]\(c\)[/tex] is the specific heat capacity of the substance,
- [tex]\(\Delta T\)[/tex] is the change in temperature.
The sum of the heats gained and lost is zero:
[tex]\[ Q_{\text{water}} + Q_{\text{ethanol}} = 0 \][/tex]
Since the final temperature is the same for both substances, we can write the equation:
[tex]\[ m_{\text{water}}c_{\text{water}}\Delta T_{\text{water}} + m_{\text{ethanol}}c_{\text{ethanol}}\Delta T_{\text{ethanol}} = 0 \][/tex]
Rearrange the equation to solve for the final temperature [tex](\(T_{\text{final}}\))[/tex]:
[tex]\[ \Delta T_{\text{water}} + \Delta T_{\text{ethanol}} = 0 \][/tex]
[tex]\[ T_{\text{final}} - T_{\text{initial, water}} + T_{\text{final}} - T_{\text{initial, ethanol}} = 0 \][/tex]
[tex]\[ 2T_{\text{final}} = T_{\text{initial, water}} + T_{\text{initial, ethanol}} \][/tex]
[tex]\[ T_{\text{final}} = \frac{T_{\text{initial, water}} + T_{\text{initial, ethanol}}}{2} \][/tex]
Now, substitute the given values:
[tex]\[ T_{\text{final}} = \frac{(55.0 \ \text{mL} \times 1.0 \ \text{g/mL} \times 4.18 \ \text{J/g}^\circ\text{C} \times (28.6^\circ\text{C} - T_{\text{final}})) + (55.0 \ \text{mL} \times 0.789 \ \text{g/mL} \times 2.44 \ \text{J/g}^\circ\text{C} \times (T_{\text{final}} - 9.0^\circ\text{C}))}{2} \][/tex]
[tex]\[ T_{\text{final}} = \frac{(55.0 \ \text{mL} \times 4.18 \ \text{J/g}^\circ\text{C} \times (28.6^\circ\text{C} - T_{\text{final}})) + (55.0 \ \text{mL} \times 0.789 \ \text{g/mL} \times 2.44 \ \text{J/g}^\circ\text{C} \times (T_{\text{final}} - 9.0^\circ\text{C}))}{2} \][/tex]
Combine like terms:
[tex]\[ T_{\text{final}} = \frac{(55.0 \times 4.18 \times 28.6) + (55.0 \times 0.789 \times 2.44 \times (T_{\text{final}} - 9.0))}{2} \][/tex]
[tex]\[ T_{\text{final}} = \frac{(6132.86 + 107.79 \times (T_{\text{final}} - 9.0))}{2} \][/tex]
[tex]\[ T_{\text{final}} = \frac{6132.86 + 107.79T_{\text{final}} - 971.1}{2} \][/tex]
[tex]\[ 2T_{\text{final}} = 7101.76 + 107.79T_{\text{final}} - 971.1 \][/tex]
Combine like terms:
[tex]\[ 2T_{\text{final}} - 107.79T_{\text{final}} = 7101.76 - 971.1 \][/tex]
[tex]\[ -105.79T_{\text{final}} = 6130.66 \][/tex]
[tex]\[ T_{\text{final}} \approx -57.97^\circ\text{C} \][/tex]
Therefore, the final temperature of the mixture is approximately [tex]\(-57.97^\circ\text{C}\)[/tex]. This negative value indicates that the final temperature is lower than the initial temperatures of water and ethanol, which is consistent with the fact that heat is transferred from the substances with higher initial temperatures to the one with a lower initial temperature.
At 40 C H2O2(aq) will decompose according to the following reaction:
2H2O2 (aq) -----> 2H2O (l) + O2 (g)
The following data were collected for the concentration of H2O2 at various times:
Time (s) H2O2 (mol/L)
1.000 2.16 x 10^4
0.500 4.32 x 10^4
(a) calculate the average rate of decomposition of H2O2 between0 and 2.16 x 104 s. Use this rate to calculate the averagerate of production of O2 (g) over the same time period.
(b) what are these rates for the time period 2.16 x 104 s to4.32 x 104 s ?
Answer:
a. 1,157x10⁻⁵M/s
b. 5,787x10⁻⁶M/s
Explanation:
For the reaction:
2H₂O₂(aq) → 2H₂O(l) + O₂(g).
a. The rate law of descomposition is:
[tex]rate=-\frac{1}{2} \frac{d[H_{2}O_{2}]}{dt}=\frac{d[O_{2}]}{dt}[/tex]
Where d[H₂O₂] is the change in concentration of H₂O₂ (between 0s and 2,16x10⁴s) is (1,000M-0,500M) and dt is (0s-2,16x10^4s). Replacing:
[tex]rate=-\frac{1}{2} \frac{0,500M}{-2,16x10^4s}[/tex]
[tex]rate=1,157x10^{-5}M/s[/tex]
As this rate is = d[O₂]/dt(Rate of production of O₂), the rate of production of O₂(g) is 1,157x10⁻⁵M/s
b. Between 2,16x10⁴s and 4,32x10⁴s, rate law is:
[tex]rate=-\frac{1}{2} \frac{0,500M-0,250M}{2,16x10^4s-4,32x10^4s}[/tex]
[tex]rate=5,787x10^{-6}M/s[/tex]
The rates are 5,787x10⁻⁶M/s
I hope it helps!
The study of chemicals and bonds is called chemistry. There are two types of elements these rare metals and nonmetals.
Thus the rate is,
[tex]rate=1157\times10^{-5}[/tex]
What is rate law?The rate law or rate equation for a chemical reaction is an equation that links the initial or forward reaction rate with the concentrations or pressures of the reactants and constant parameters.
The balanced reaction is:-
[tex]2H_2O_2(aq)----->2H_2O(l)+o_2(g)[/tex]
The rate law of decomposition:-
[tex]rate=-\dfrac{1}{2}\dfrac{d[H_2O_2]}{dt}[/tex]
Where d[H₂O₂] is the change in concentration of H₂O₂ (between 0s and 2,16x10⁴s) is (1,000M-0,500M) and dt is (0s-2,16x10^4s). Replacing:
[tex]rate=-\dfrac{1}{2}\dfrac{0.5}{2.16\times10^{4}}[/tex]
[tex]rate=1157\times10^{-5}[/tex]
As this rate is = d[O₂]/dt(Rate of production of O₂), the rate of production of O₂(g) is 1,157x10⁻⁵M/s
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Select the true statements about the electron transport chain. In the electron transport chain, a series of reactions moves electrons through carriers. The products of the electron transport chain are and either or . Coenzyme Q and cytochrome are components of the electron transport chain. Coenzyme A is a component of the electron transport chain. The electron transport chain operates independently of other metabolic processes.
Answer:
The true statements are given below.
Explanation:
1 In the electron transport chain a series of reactions moves electrons through carriers.
2 Coenzyme Q and cytochrome are the components of the electron transport chain.
During electron transport chain electrons are transported from one electron carrier have high reduction potential to another electron carrier having comparatively low reduction potential than the previous one by a series of redox reactions.
Coenzyme Q is a component of complex 2 whereas cytochrome is an important component of both complex 3 and complex 4.
The electron transport chain is a series of reactions that moves electrons through carriers and is located in the inner mitochondrial matrix in eukaryotic cells and the cytoplasmic membrane in prokaryotic cells. Its products are water and ATP. Coenzyme Q and cytochrome are components of the electron transport chain, but Coenzyme A is not. The electron transport chain operates independently of other metabolic processes.
Explanation:The electron transport chain (ETC) is a series of reactions that moves electrons through carriers. It is located in the inner mitochondrial matrix in eukaryotic cells and the cytoplasmic membrane in prokaryotic cells. The products of the electron transport chain are water and ATP. Coenzyme Q and cytochrome are components of the electron transport chain, but Coenzyme A is not. The electron transport chain operates independently of other metabolic processes.
Which statement is FALSE? a. ΔHrxn is the heat of reaction. b. ΔErxn is a measure of heat. c. An exothermic reaction gives heat off heat to the surroundings. d. Endothermic has a positive ΔH. e. Enthalpy is the sum of a system's internal energy and the product of pressure and volume.
Answer:
b. ΔE rxn is a measure of heat
Explanation:
a. ΔHrxn is the heat of reaction. TRUE. ΔHrxn or change in enthalpy of reaction is per definition the change in heat that is involved in a chemical reaction.
b. ΔErxn is a measure of heat. FALSE. Is the change in internal energy of a reaction
c. An exothermic reaction gives heat off heat to the surroundings. TRUE. An exothermic reaction is a chemical reaction that releases heat.
d. Endothermic has a positive ΔH. TRUE. When a process is exothermic ΔH<0 and when the process is endothermic ΔH>0
e. Enthalpy is the sum of a system's internal energy and the product of pressure and volume. TRUE. Under constant pressure and volume the formula is ΔH = ΔE + PV
I hope it helps!
The statement that is FALSE is b. ΔErxn is a measure of heat.
Explanation:The statement that is FALSE is b. ΔErxn is a measure of heat.
ΔErxn is the change in internal energy of a system, not a direct measure of heat. It is related to heat through the equation ΔErxn = q + w, where ΔErxn is the change in internal energy, q is the heat transferred, and w is the work done on or by the system. Enthalpy, on the other hand, is a measure of heat at constant pressure, and is given by ΔHrxn = q (heat of reaction).
Therefore, option b is the false statement.
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Suppose a 250.0 mL flask is filled with 1.3mol of I2 and 1.0mol of HI. The following reaction becomes possible:
H2 (g) +I2 (g)=2HI (g)
The equilibrium constant K for this reaction is 0.983 at the temperature of the flask.
Calculate the equilibrium molarity of HI . Round your answer to one decimal place.
Answer:
The molarity of HI at the equilibrium is 2.8M
Explanation:
Step 1: Data given
Volume of the flask = 250.0 mL = 0.250L
Number of moles I2 = 1.3 mol
Number of moles HI = 1.0 mol
Kc = 0.983
Step 2: The balanced equation
H2(g) +I2(g) ⇆ 2HI(g)
For 1 mole I2 consumed, we need 1 mole H2 to produce 2 moles HI
Step 3: Calculate initial concentrations
Initial concentration I2 = 1.3mol / 0.25L
Initial concentration I2 = 5.2 M
Initial concentration HI = 1.0 mol / 0.25L
Initial concentration HI = 4.0 M
Step 4: Calculate concentrations at equilibrium
The concentration at equilibrium is:
[I2] = (5.2+x)M
[HI] = (4.0 - x)M
[H2] = xM
Kc = [HI]²/[H2][I2]
0.983 = (4-x)²/ (x*(5.2+x))
0.983 = (4-x)²/ (5.2x +x²)
5.1116x + 0.983 x² = 16 -8x +x²
-0.017x² +13.1116x -16 = 0
x = 1.222 = [H2]
[HI] = 4.0 - 1.222 = 2.778M ≈ 2.8 M
[I2] = 5.2 + 1.222 = 6.422 M ≈ 6.4 M
To control we can calculate:
[2.778]² / [1.222][6.422] = 0.983 = Kc
The molarity of HI at the equilibrium is 2.8M
Under which of the following sets of conditions will a sample of a real gas deviate most from ideal behavior? a. strong interparticle attractions, low temperature, high pressure b. strong interparticle attractions, high temperature, high pressure c. weak interparticle attractions, low temperature, high pressure d. weak interparticle attractions, high temperature, high pressure e. strong interparticle attractions, low temperature, low pressure
Answer:
a. strong interparticle attractions, low temperature, high pressure.
Explanation:
A gas behaves as an ideal gas when it fulfills the following conditions:
The interparticle attractions are neglectable.The volume of the gas is neglectable in comparison with the volume of the container.The gas deviates from the ideal behavior:
When there are strong interparticle attractions.At low temperatures and high pressures, the particles are closer to each other and interparticle attractions are stronger.A real gas deviates most from ideal behavior under the conditions of strong interparticle attractions, low temperature, and high pressure.
Explanation:A real gas deviates most from ideal behavior under the following set of conditions: strong interparticle attractions, low temperature, high pressure.
When a real gas has strong interparticle attractions, the gas particles are more likely to stick together and deviate from ideal behavior. Low temperature also contributes to the deviation as it slows down the gas particles and makes the attractive forces between them more prominent. High pressure further increases the deviation due to the decrease in empty space between the particles.
In summary, a real gas deviates most from ideal behavior when it has strong interparticle attractions, low temperature, and high pressure.
Draw the product of nucleophilic substitution with each neutral nucleophile. When the initial substitution product can lose a proton to form a neutral product, draw the product after proton transfer
Answer:
Neutral nucleophile are: H2O, CH3OH, NH3, RNH2, R2NH, R3N, RCOOH, RSH and PR3. The products by nucleophilic substitution are diverse depending on the different nucleophiles, obtaining alcohol, eter, amines, ester and tioeter considering only the nucleophiles with a hydrogen available.
Explanation:
Please see the images attached.
Nucleophilic subtitution with water occurs under Sn1 mechanism. That's it because water as nucleophile is so weak. With the other neutral nucleophiles, the reaction occur under Sn2 mechanism.
RSH + CH3I -----> RSCH3 + HI
Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C. Zn(s) + 2H+ (aq) → Zn2+(aq) + H2(g) Assume the volume of reactants is negligible compared to that of the vapor produced.
Answer:
19,26 kJ
Explanation:
The work done when a gas expand with a constant atmospheric pressure is:
W = PΔV
Where P is pressure and ΔV is the change in volume of gas.
Assuming the initial volume is 0, the reaction of 500g of Zn with H⁺ (Zn(s) + 2H⁺(aq) → Zn²⁺(aq) + H₂(g)) produce:
500,0g Zn(s)×[tex]\frac{1molZn}{65,38g}[/tex]×[tex]\frac{1molH_{2}(g)}{1molZn}[/tex] = 7,648 moles of H₂
At 1,00atm and 303,15K (30°C), the volume of these moles of gas is:
V = nRT/P
V = 7,648mol×0,082atmL/molK×303,15K / 1,00atm
V = 190,1L
That means that ΔV is:
190,1L - 0L = 190,1L
And the work done is:
W = 1atm×190,1L = 190,1atmL.
In joules:
190,1 atmL×[tex]\frac{101,325}{1atmL}[/tex] = 19,26 kJ
I hope it helps!
The amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C is approximately 19601.44 joules.
The amount of work done against an atmospheric pressure when a gas is produced can be calculated using the ideal gas law, which is given by PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.
First, we need to determine the number of moles of hydrogen gas (H2) produced from the dissolution of 500.0 g of zinc. The balanced chemical equation is:
[tex]\[ \text{Zn}(s) + 2\text{H}^+(aq) \rightarrow \text{Zn}^{2+}(aq) + \text{H}_2(g) \][/tex]
From the stoichiometry of the reaction, 1 mole of zinc produces 1 mole of hydrogen gas. The molar mass of zinc is approximately 65.38 g/mol. Therefore, the number of moles of zinc (n_Zn) is:
[tex]\[ n_{\text{Zn}} = \frac{\text{mass of Zn}}{\text{molar mass of Zn}} = \frac{500.0 \text{ g}}{65.38 \text{ g/mol}} \approx 7.647 \text{ mol} \][/tex]
Since the stoichiometry is 1:1, the number of moles of hydrogen gas produced (n_H2) is also approximately 7.647 moles.
Next, we convert the temperature from degrees Celsius to Kelvin:
[tex]\[ T = 30.0^\circ\text{C} + 273.15 = 303.15 \text{ K} \][/tex]
Now, we can use the ideal gas law to find the volume of hydrogen gas produced at 1.00 atm of pressure:
[tex]\[ PV = nRT \][/tex]
[tex]\[ V = \frac{nRT}{P} \][/tex]
Plugging in the values:
[tex]\[ V = \frac{(7.647 \text{ mol})(0.0821 \text{ L·atm/mol·K})(303.15 \text{ K})}{1.00 \text{ atm}} \][/tex]
[tex]\[ V \approx 193.57 \text{ L} \][/tex]
Finally, the work done (W) against the atmospheric pressure to produce this volume of hydrogen gas is given by:
[tex]\[ W = P \cdot V \][/tex]
[tex]\[ W = 1.00 \text{ atm} \cdot 193.57 \text{ L} \][/tex]
[tex]\[ W \approx 193.57 \text{ L·atm} \][/tex]
To express this work in joules, we use the conversion factor[tex]1 L*atm[/tex] = [tex]101.325 J:[/tex]
[tex]\[ W \approx 193.57 \text{ L·atm} \times \frac{101.325 \text{ J}}{1 \text{ L·atm}} \][/tex]
[tex]\[ W \approx 19601.44 \text{ J} \][/tex]
Therefore, the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C is approximately 19601.44 joules.
The answer is: [tex]19601.44 \text{ J}.[/tex]
24.711 g sample of aqueous waste leaving a fertilizer manufacturer contains ammonia. The sample is diluted with 79.741 g of water. A 11.169 g aliquot of this solution is then titrated with 0.1045 M HCl . It required 28.42 mL of the HCl solution to reach the methyl red endpoint. Calculate the weight percent NH3 in the aqueous waste.
Final answer:
The weight percent of NH3 in the aqueous waste was calculated from the titration data to be 0.2047%. The moles of NH3 were found to be 0.0029711 mol, corresponding to 0.050585g NH3 in the original waste sample.
Explanation:
The weight percent of NH3 in the aqueous waste is calculated using titration analysis. First, determine the moles of HCl that reacted:
# mol HCl = 0.02842 L × 0.1045 M = 0.0029711 mol HCl.
The reaction between HCl and NH3 is:
NH3(aq) + HCl(aq) → NH4Cl(aq).
Hence, 1 mole of HCl reacts with 1 mole of NH3. Therefore, the moles of NH3 in the aliquot are also 0.0029711 mol. To find the mass of NH3:
Mass of NH3 = moles × molar mass
= 0.0029711 mol × 17.031 g/mol
= 0.050585 g NH3.
Since the aliquot is part of the diluted waste, and assuming the ammonia is evenly distributed, we calculate the weight percent in the original waste sample:
Weight percent = (mass of NH3 in aliquot / mass of waste sample) × 100
= (0.050585 g / 24.711 g) × 100
= 0.2047%.
Be sure to answer all parts. A 0.365−mol sample of HX is dissolved in enough H2O to form 835.0 mL of solution. If the pH of the solution is 3.70, what is the Ka of HX? Be sure to report your answer to the correct number of significant figures.
The Ka of HX is mathematically given as
Ka = 9.11 *10^-8
What is the Ka of HX?
Generally, the equation for the molarity of HX is mathematically given as
M HX = moles HX / volume solution
Therefore
Molarity HX = 0.365 mol / 0.835 L
Molarity HX = 0.437 M
Therefore, ICE-chart
[H+] = [H3O+]
10^-3.70 = 10^-3.70 = 1.995 *10^-4
The concentration at the equilibrium is
[HX] = (0.437 - x)M
[H3O+] = 1.995*10^-4 M
x=1.995*10^-4
In conclusion
Ka = [X-]*[H3O+] / [HX]
Ka = ((1.995*10^-4)²)/ 0.437
Ka = 9.11 *10^-8
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Final answer:
The Ka of HX, given its concentration and the pH of solution, can be determined through a series of calculations leading to a Ka value of 9.17×10-8.
Explanation:
To find the Ka of HX given a 0.365-mol sample dissolved in 835.0 mL of solution with a pH of 3.70, we start by calculating the concentration of HX, then use the pH to find the concentration of H+ ions, which will help determine the acid dissociation constant (Ka).
First, convert volume from mL to L: 835.0 mL = 0.835 L. The concentration of HX (Molarity, M) is moles of solute (HX) divided by volume of solution in liters, which is 0.365 mol / 0.835 L = 0.4371 M.
Given pH = 3.70, we calculate the concentration of H+ ions ([H+]) as 10-pH = 10-3.70 = 2.00×10-4 M.
Assuming all H+ comes from the dissociation of HX and ignoring autoionization of water because HX is a weak acid, the Ka expression for HX is Ka = [H+][X-] / [HX]. Assuming the concentration of [X-] is equal to [H+] because each molecule of HX donates one H+, Ka becomes 2.00×10-4 M * 2.00×10-4 M / 0.4371 M = 9.17×10-8, after considering the initial concentration of HX and the change in concentration due to dissociation.
A major component of gasoline is octane . When octane is burned in air, it chemically reacts with oxygen gas to produce carbon dioxide and water . What mass of oxygen gas is consumed by the reaction of of octane? Be sure your answer has the correct number of significant digits.
Answer:
mass of O₂ = 800 g
Explanation:
Formula of Octane = C₈H₁₈
Formula of Oxygen = O₂
Balanced Chemical Reaction:
Octane react with oxygen and produce water and carbon dioxide.
2C₈H₁₈ + 25O₂ ---------> 16CO₂+ 18H₂O
Moles calculation:
From the number of moles of the reactant used in a chemical reaction specific number of product produced. we can find the amount of any reactant and product from the mole ratio of a chemical reaction.
Mole formula =
no. of moles = mass in grams / molecular mass ............... (1)
Given Data:
Molecular Weight of O₂ = (16 x2 ) = 32 g/mol
Mass of O₂ = To be find
Calculations:
2C₈H₁₈ + 25O₂ ---------> 16CO₂ + 18H₂O
2mole 25 mole 16 mole 18 mole
From the above balanced chemical equation it is know that 2 mole of octane consume 25 mole of oxygen.
so we have to calculate the mass of oxygen that is consumed
by using mole formula (1) we can fine the mass of oxygen
we know
Molecular Weight of O₂ = 32 g/mol
number of moles of Oxygen molecule = 25 mol
putting the value in the below formula
no. of moles of O₂ = mass of O₂ / molecular mass of O₂
25 mole = mass of O₂ / 32 g/mol ....... (2)
By rearragming the equation (2)
mass of O₂ = 25 mole x 32 g/mol
mass of O₂ = 25 mole x 32 g/mol
mass of O₂ = 800 g
So in the octan reaction with oxygen 800g of oxygen will use.
Propane is often used to heat homes. The combustion of propane follows the following reaction: C3H8(g) + 5O2(g) 3CO2 (g) + 4H2O(g), ΔH° = –2044 kJ. How many grams of propane must be reacted by this reaction to release 7563 kJ of heat?
Answer:
To release 7563 kJ of heat, we need to burn 163.17 grams of propane
Explanation:
Step 1: Data given
C3H8 + 5O2 -----------> 3CO2 + 4H2O ΔH° = –2044 kJ
This means every mole C3H8
Every mole of C3H8 produces 2044 kJ of heat when it burns (ΔH° is negative because it's an exothermic reaction)
Step 2: Calculate the number of moles to produce 7563 kJ of heat
1 mol = 2044 kJ
x mol = 7563 kJ
x = 7563/2044 = 3.70 moles
To produce 7563 kJ of heat we have to burn 3.70 moles of C3H8
Step 3: Calculate mass of propane
Mass propane = moles * Molar mass
Mass propane = 3.70 moles * 44.1 g/mol
Mass propane = 163.17 grams
To release 7563 kJ of heat, we need to burn 163.17 grams of propane
The mass of propane needed by the reaction to release 7563 KJ of heat energy is 162.8 g
Balanced equationC₃H₈ + 5O₂ —> 3CO₂ + 4H₂O ΔH° = –2044 KJ
Molar mass of propane C₃H₈ = (3×12) + (1×8) = 44 g/mol
Mass of propane C₃H₈ from the balanced equation = 1 × 44 = 44 g
Heat released = 2044 KJ
SUMMARY
From the balanced equation above,
2044 KJ of heat was released by the reaction of 44 g of propane
How to determine the mass of propane neededFrom the balanced equation above,
2044 KJ of heat was released by the reaction of 44 g of propane
Therefore,
7563 KJ of heat energy will be release by = (7563 × 44) / 2044 = 162.8 g of propane
Thus, 162.8 g of propane is needed for the reaction
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Predict the sign of the entropy change, ΔS∘, for each of the reaction displayed.Drag the appropriate items to their respective bins: Positive, NegativeAg+(aq)+Br−(aq)→AgBr(s)CaCO3(s)→CaO(s)+CO2(g)2NH3(g)→N2(g)+3H2(g)2Na(s)+Cl2(g)→2NaCl(s)C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)I2(s)→I2(g)
The predicted sign of the entropy change in each reaction are as follows;
Ag+(aq). + Br−(aq) → AgBr(s). --NegativeCaCO3(s) → CaO(s)+CO2(g) --Positive2NH3(g) → N2(g)+3H2(g) --Positive2Na(s). + Cl2(g) → 2NaCl(s) --NegativeC3H8(g)+5O2(g)→3CO2(g)+4H2O(g) --PositiveI2(s) → I2(g). --PositiveTo solve this question, we must understand the meaning of entropy.
Entropy of a system or chemical entity is the degree of disorderliness in the substance.
The change in entropy, ΔS∘ is a measure of the difference between the entropy of products and the reactants and is given mathematically as;
ΔS∘ = S(products) - S(reactants).We must also know that the entropy of a gas is greater than a liquid and that in turn is greater than a solid.The statement above therefore provides a basis for predicting the sign of the entropy change; ΔS∘ in each reaction.Read more:
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In the first reaction entropy sign is negative while for the second reaction the sign on entropy is positive.
The Entropy is defined as degree of disorderliness in the system.
When entropy is negative the reaction will be non-spontaneous.When entropy id positive the reaction will be spontaneous.The entropy of the reaction can be calculated by,
[tex]\rm \bold{ \Delta S = S(products) - S(reactants)}[/tex]
Entropy for First reaction,
[tex]\rm \bold{ Ag(aq) + Br(aq) \rightarrow AgBr(s)}[/tex] will be negative
Entropy for second reaction,
[tex]\rm \bold{ CaCO_3(s) \rightarrow CaO(s)+CO_2(g) }[/tex] will be positive.
Hence, we can conclude that the the first reaction will be non- spontaneous while second reaction will spontaneous.
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Calculate how many times more soluble Mg(OH)2 is in pure water Based on the given value of the Ksp, 5.61×10−11, calculate the ratio of solubility of Mg(OH)2 dissolved in pure H2O to Mg(OH)2 dissolved in a 0.130 M NaOH solution.
molar solubility in water = 2.41 x 10^-4
molar solubility of NaOH in 0.130M = 3.32 x 10^-9
Final answer:
The molar solubility of Mg(OH)2 in pure water is 2.41 x 10^-4 M. To calculate the molar solubility in a 0.130 M NaOH solution, we can use the common ion effect.
Explanation:
The molar solubility of Mg(OH)2 in pure water is 2.41 x 10^-4 M. The molar solubility of Mg(OH)2 in a 0.130 M NaOH solution can be determined using the common ion effect. Since NaOH dissociates into Na+ and OH-, the concentration of OH- in the NaOH solution is 0.130 M. To calculate the molar solubility, we can set up an ICE table:
Mg(OH)2 ⇌ Mg2+ + 2OH-
Initial: 0.130 M (from NaOH concentration)
Change: -x (due to dissolution of Mg(OH)2) and +2x (due to formation of OH- ions)
Equilibrium: 0.130 - x M
Ksp = (Mg2+)(OH-)²
Using the given value of the Ksp, 5.61x10^-11, we can substitute the equilibrium concentrations into the Ksp expression and solve for x. Then we can calculate the ratio of the solubility of Mg(OH)2 in pure water to the solubility in the NaOH solution by dividing the molar solubility in water by the molar solubility in the NaOH solution.
Mg(OH)₂ is approximately [tex]\( 0.472} \)[/tex] times more soluble in pure water compared to a 0.130 M NaOH solution. The solubility of Mg(OH)₂ in the presence of 0.130 M NaOH, is approximately [tex]\( 5.1 \times 10^{-4} \)[/tex] M.
To determine how many times more soluble Mg(OH)₂ is in pure water compared to a 0.130 M NaOH solution, we need to consider the effect of the common ion (OH-) from NaOH on the solubility of Mg(OH)₂.
Given:
- [tex]\( K_{sp} \)[/tex] for Mg(OH)₂ in pure water = [tex]\( 5.61 \times 10^{-11} \)[/tex]
- Molar solubility of Mg(OH)₂ in pure water = [tex]\( 2.41 \times 10^{-4} \)[/tex] M
- Molar solubility of NaOH in 0.130 M solution = [tex]\( 3.32 \times 10^{-9} \)[/tex] M
1. Calculate the concentration of OH- ions in the 0.130 M NaOH solution:
The NaOH dissociates completely to produce Na+ and OH- ions.
Concentration of OH- ions from NaOH = 0.130 M
2. Determine the solubility of Mg(OH)₂ in the presence of 0.130 M NaOH:
According to the common ion effect, the presence of additional OH- ions from NaOH will shift the equilibrium of Mg(OH)2 dissolution. The solubility of Mg(OH)₂ will decrease due to the Le Chatelier's principle, which states that adding an ion that is involved in the equilibrium reaction will shift the equilibrium in the direction that reduces its effect.
Let's denote the solubility of Mg(OH)₂ in the presence of 0.130 M NaOH as [tex]\( S_{\text{NaOH}} \)[/tex].
Using the Ksp expression for Mg(OH)₂:
[tex]\[ K_{sp} = [\text{Mg}^{2+}][\text{OH}^-]^2 \][/tex]
In pure water, [tex]\( [\text{OH}^-] = S_{\text{water}} \)[/tex] (molar solubility of Mg(OH)2 in pure water).
In the presence of 0.130 M NaOH, [tex]\( [\text{OH}^-] = 3.32 \times 10^{-9} \)[/tex]M (concentration of OH- from NaOH).
So, [tex]\( S_{\text{NaOH}} \)[/tex] can be found from:
[tex]\[ K_{sp} = [\text{Mg}^{2+}](3.32 \times 10^{-9})^2 \][/tex]
Solve for [tex]\( [\text{Mg}^{2+}] \)[/tex]:
[tex]\[ [\text{Mg}^{2+}] = \frac{K_{sp}}{(3.32 \times 10^{-9})^2} \][/tex]
Calculate [tex]\( [\text{Mg}^{2+}] \)[/tex]:
[tex]\[ [\text{Mg}^{2+}] = \frac{5.61 \times 10^{-11}}{(3.32 \times 10^{-9})^2} \][/tex]
[tex]\[ [\text{Mg}^{2+}] = \frac{5.61 \times 10^{-11}}{1.1 \times 10^{-17}} \][/tex]
[tex]\[ [\text{Mg}^{2+}] \approx 5.1 \times 10^{-4} \, \text{M} \][/tex]
3. Calculate the ratio of solubility in pure water to solubility in 0.130 M NaOH:
[tex]\[ \text{Ratio} = \frac{S_{\text{water}}}{S_{\text{NaOH}}} = \frac{2.41 \times 10^{-4}}{5.1 \times 10^{-4}} \][/tex]
[tex]\[ \text{Ratio} \approx 0.472 \][/tex]
A buret is filled with 0.1517 M A 25.0 mL portion of an unknown acid and two drops of indicator are added to an Erlenmeyer flask, and the titration experiment is carried out. If the initial buret reading was 0.55 mL, and the buret reading at the end point was 22.50 mL, what is the molarity of the unknown acid, HA?
Answer:
Molarity of Unknown Acid = 0.1332 M
Explanation:
Data for solving problem:
Molarity of base in buret (M₁)= 0.1517 M
volume of the acid in Erlenmeyer flask (V₂)= 25.0 mL
Volume of the base in the buret (V₁) = final volume of buret - initial volume in buret
final volume of buret = 22.5 mL
initial volume in buret = 0.55 mL
So
Volume of the base in the buret (V₁) = 22.5 mL -0.55 mL = 21.95 mL
Volume of the base in the buret (V₁) = 21.95 mL
Molarity of Unknown acid in the Erlenmeyer flask (M₂) = To be find
Explanation:
It is acid base titration and formula for this titration is as follows:
Molarity of base x Volume of base = Molarity of acid x volume of acid
it can be written as
M₁V₁ = M₂V₂ -------------------- equation (1)
we have to find M₂
so by rearrangment the equation (1)
M₁V₁ / V₂ = M₂ ------------------ equation (2)
put the values in equation in equation (2)
M₂ = 0.1517 M x 21.95 mL / 25.0 mL
M₂ = 3.3298 /25.0
M₂ = 0.1332 M
so the Molarity of Unknown acid is 0.1332 M
The molarity of the unknown acid HA is calculated to be 0.1331 M by first determining the moles of NaOH that reacted and then using the volume of acid to find its concentration.
To determine the molarity of the unknown acid HA in a titration experiment, first, we calculate the volume of 0.1517 M NaOH used by subtracting the initial buret reading from the final buret reading: 22.50 mL - 0.55 mL = 21.95 mL. This volume is then converted to liters by dividing by 1000: 21.95 mL/1000 = 0.02195 L. Next, we use the molarity of the NaOH solution to find the moles of NaOH that have reacted: 0.1517 M × 0.02195 L = 0.003328665 moles.
Assuming a 1:1 mole ratio between NaOH and HA in the reaction, the moles of unknown acid HA that reacted are also 0.003328665. We then calculate the molarity of the unknown acid, by dividing moles of acid by the volume of acid in liters (25.0 mL = 0.025 L): 0.003328665 moles / 0.025 L = 0.1331466 M.
The molarity of the unknown acid HA is therefore 0.1331 M, rounded to four significant figures to match the precision of the given data.
A 3.452 g sample containing an unknown amount of a Ce(IV) salt is dissolved in 250.0 mL of 1 M H2SO4. A 25.00 mL aliquot is analyzed by adding KI and titrating the I3^- that forms with S2O3^2-. The end point was reached following the addition of 13.02 mL of 0.03247 M Na2S2O3. Calculate the weight percent of Ce^4+ in the sample?
Answer:
The weight percent in the sample is 17,16%
Explanation:
The dissolution of the Ce(IV) salt provides free Ce⁴⁺ that reacts, thus:
2Ce⁴⁺ + 3I⁻ → 2Ce³⁺ + I₃⁻
I₃⁻ + 2S₂O₃²⁻ → 3I⁻ + S₄O₆²⁻
The moles in the end point of S₂O₃⁻ are:
0,01302L×0,03247M Na₂S₂O₃ = 4,228x10⁻⁴ moles of S₂O₃²⁻.
As 2 moles of S₂O₃⁻ react with 1 mole of I₃⁻, the moles of I₃⁻ are:
4,228x10⁻⁴ moles of S₂O₃⁻×[tex]\frac{1molI_{3}^-}{2molS_{2}O_{3}^{2-}}[/tex] = 2,114x10⁻⁴ moles of I₃⁻
As 2 moles of Ce⁴⁺ produce 1 mole of I₃⁻, the moles of Ce⁴⁺ are:
2,114x10⁻⁴ moles of I₃⁻× [tex]\frac{2molCe^{4+}}{1molI_{3}^-}[/tex] = 4,228x10⁻⁴ moles of Ce(IV).
These moles are:
4,228x10⁻⁴ moles of Ce(IV)×[tex]\frac{140,116g}{1mol}[/tex] = 0,05924 g of Ce(IV)
As was taken an aliquot of 25,00mL from the solution of 250,0mL:
0,05924 g of Ce(IV)×[tex]\frac{250,0mL}{25,00mL}[/tex] =0,5924g of Ce(IV) in the sample
As the sample has 3,452g, the weight percent is:
0,5924g of Ce(IV) / 3,452g × 100 = 17,16 wt%
I hope it helps!
Which of the following is NOT a standard state? Group of answer choices For a solid, it is 1 atm. For a solid, it is 25°C. For a liquid, it is 1 atm. For a liquid, it is 25°F. For a solution, it is 1 M.
Answer:
For a liquid, it is 25°F
Explanation:
The standard state for a liquid is 25°C
The state which is not a standard state for solid is 25 °C and for liquid is 25 F.
What are standard state?Every matter will behave idealy at a particular set of items and that set is known as standard state of that matter.
For solids:Solids will remain at the standard state at 1 atm pressure, but 25°C (298K) is not the standard temperature for solids as they will melt in this temperature.
For liquids:Standard state of liquids is 1 atm pressure and 25°C (298K) temperature, but in the question it is given 25F which is not true so.
For solution:Solution of 1 molariy will consider as the standard solution and it is define as the number of moles of solute present in per liter of the solution.
So, for solids and liquids 25°C and 25F respectively is not a standard state.
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Determine the volume fraction of fibers required to obtain a longitudinal tensile strength of 812 MPa in a unidirectional carbon fiber reinforced composite. You are given that the tensile strength of the carbon fibers are 1240 MPa and that the stress in the matrix at fiber failure will be 300 MPa. Answer Format X.XX Unit: Unitless (fraction, example: 50 vol% fiber would be entered as 0.50)
Answer:
V= 0.544
Explanation:
Given that
σ=812 MPa
σ₁=1240 MPa
σ₂=300 MPa
Lets take volume fraction V
The strength of composite fiber given as
σ = σ₁ V + σ₂(1-V)
By putting the values
812 = 1240 V + 300 (1-V)
812 = 1240 V +300 - 300 V
812 - 300 = 1240 V- 300 V
512 = 940 V
V= 0.544
The percentage volume = 54.4 %
In addition to running aspartic acid, phenylalanine, aspartame and hydrolyzed aspartame, let's assume that you also ran leucine on your TLC plate in this lab. Would you expect leucine to travel farther than or less than aspartic acid, and why?
A. Leucine is nonpolar, thus it should travel farther than aspartc acid on my TLC plate
B. Leucine is polar, thus i should travel less than aspartic acid on my TLC plate
C. Leucine is polar, thus it should travel farther than aspartic acid on my TLC plate
D. Leucine is nonpolar, thus should travel less than aspartic acid on my TLC plate.
Final answer:
Leucine, being nonpolar, should travel farther than the polar amino acid aspartic acid on a TLC plate because nonpolar substances have a higher affinity for the stationary phase and a lower affinity for the polar mobile phase.
Explanation:
On a thin-layer chromatography (TLC) plate, the distance that a compound travels is closely related to its polarity. In this lab experiment, leucine is a nonpolar amino acid, while aspartic acid is polar due to its acidic side chain. Therefore, leucine should travel farther on the TLC plate than aspartic acid because the nonpolar amino acids have a higher affinity for the nonpolar stationary phase and a lower affinity for the polar mobile phase, so they're carried less distance by the solvent front.
The correct answer to this question is A. Leucine is nonpolar, thus it should travel farther than aspartic acid on my TLC plate.
Identify which sets of quantum numbers are valid for an electron. Each set is ordered (n,l,ml,ms).a. 3,1,1,-1/2b. 4,3,1,-1/2c. 2,0,0,-1/2d. 1,3.0,1/2e. 3,2,-1,-1/2f. 3,3,-1,1/2g. 3,2,1,-1h. 1,-1,-1,-1/2i. 3,3,1,1/2j. 3,0,0,1/2k. 4,3,4,-1/2l. 0,2,1,1/2
Answer:
The valid set of quantum numbers are:
a. 3,1,1,-1/2
b. 4,3,1,-1/2
c. 2,0,0,-1/2
e. 3,2,-1,-1/2
j. 3,0,0,1/2
Explanation:
Quantum numbers (n, l, mℓ, ms) are the set of numbers that describe the state of an electron in an atom.
The four quantum numbers and their rules are:
Principal: n ≥ 1 Azimuthal: ℓ ≤ (n-1)Magnetic: mℓ = (- ℓ) to (+ ℓ)Spin: ms = (- s), (+ s)Therefore,
a. 3,1,1,-1/2: Valid
b. 4,3,1,-1/2: Valid
c. 2,0,0,-1/2: Valid
d. 1,3,0,1/2: NOT Valid
Reason: ℓ ≤ (n-1). Therefore, ℓ can not be greater than n, .
e. 3,2,-1,-1/2: Valid
f. 3,3,-1,1/2: NOT Valid
Reason: ℓ ≤ (n-1). Therefore, ℓ can not be equal to n. (ℓ ≠n)
g. 3,2,1,-1: NOT Valid
Reason: the only allowed values of ms = (- s), (+ s) = (- 1/2), (+ 1/2)
h. 1,-1,-1,-1/2: NOT Valid
Reason: ℓ ≤ (n-1) and n ≥ 1. Therefore, ℓ can not be equal to n and also ℓ can't be negative.
i. 3,3,1,1/2: NOT Valid
Reason: ℓ ≤ (n-1). Therefore, ℓ can not be equal to n. (ℓ ≠n)
j. 3,0,0,1/2: Valid
k. 4,3,4,-1/2: NOT Valid
Reason: mℓ = (- ℓ) to (+ ℓ). Therefore, mℓ can't be greater than ℓ.
l. 0,2,1,1/2: NOT Valid
Reason: n ≥ 1. Therefore, value of n can't be 0 (n≠0)
Which of the following is correctly balanced redox half reaction? Group of answer choices A. 14H+ + 9e- + Cr2O72- ⟶ Cr3+ + 7H2O B. 14H+ + 6e- + Cr2O72- ⟶ 2Cr3+ + 7H2O C. 14H+ + Cr2O72- ⟶ 2Cr3+ + 7H2O + 6e- D. 14H+ + Cr2O72- ⟶ Cr3+ + 7H2O + 9e-
Answer:
The correct option is: B. 14 H⁺ + 6 e⁻ + Cr₂O₇²⁻ ⟶ 2 Cr³⁺ + 7 H₂O
Explanation:
Redox reactions is an reaction in which the oxidation and reduction reactions occur simultaneously due to the simultaneous movement of electrons from one chemical species to another.
The reduction of a chemical species is represented in a reduction half- reaction and the oxidation of a chemical species is represented in a oxidation half- reaction.
To balance the reduction half-reaction for the reduction of Cr₂O₇²⁻ to Cr³⁺:
Cr₂O₇²⁻ ⟶ Cr³⁺
First the number of Cr atoms on the reactant and product side is balanced
Cr₂O₇²⁻ ⟶ 2 Cr³⁺
Now, Cr is preset in +6 oxidation state in Cr₂O₇²⁻ and +3 oxidation state in Cr³⁺. So each Cr gains 3 electrons to get reduced.
Therefore, 6 electrons are gained by 2 Cr atoms of Cr₂O₇²⁻ to get reduced.
Cr₂O₇²⁻ + 6 e⁻ ⟶ 2 Cr³⁺
Now the total charge on the reactant side is (-8) and the total charge on the product side is (+6).
From the given options it is evident that the reaction must be balanced in acidic conditions.
Therefore, to balance the total charge on the reactant and product side, 14 H⁺ is added on the reactant side.
Cr₂O₇²⁻ + 6 e⁻ + 14 H⁺ ⟶ 2 Cr³⁺
Now to balance the number of hydrogen and oxygen atoms, 7 H₂O is added on the product side.
Cr₂O₇²⁻ + 6 e⁻ + 14 H⁺ ⟶ 2 Cr³⁺ + 7 H₂O
Therefore, the correct balanced reduction half-reaction is:
Cr₂O₇²⁻ + 6 e⁻ + 14 H⁺ ⟶ 2 Cr³⁺ + 7 H₂O
Phosphoric acid (H3PO4) is important in the production of both fertilizers and detergents. It is prođuced in the following process Ca5 (PO4)3F+5H2SO4 -> 3H3PO4 +5 CaSO4 + HF. It is distributed commercially as a solution with a concentration of about 14.8 M. Approximately 2.00 x 109 gallons of this concentrated phosphoric acid solution are produced annually in this country alone. Assuming that all of this H3PO4 is produced in the reaction above, what mass (in g) of the mineral fluoroapatite, Ca5 (PO4)3F, would be required each year?
Final answer:
To calculate the mass of mineral fluoroapatite (Ca5(PO4)3F) required each year, we need to use stoichiometry. Given that approximately 2.00 x 10^9 gallons of concentrated phosphoric acid solution is produced annually containing 14.8 M concentration, we can convert this volume to moles of H3PO4 and then use stoichiometry to calculate the moles of Ca5(PO4)3F required. Finally, we can calculate the mass of Ca5(PO4)3F required, which is approximately 1.88 x 10^13 grams.
Explanation:
To calculate the mass of mineral fluoroapatite (Ca5(PO4)3F) required each year, we need to use stoichiometry.
Given that 2.00 x 109 gallons of concentrated phosphoric acid solution are produced annually, we need to convert this volume to moles of H3PO4 and then use the stoichiometric coefficients to calculate the moles of Ca5(PO4)3F required.
A balanced equation shows that for every 3 moles of H3PO4 produced, 1 mole of Ca5(PO4)3F is required.
Therefore, we can set up a ratio:
3 moles H3PO4 / 1 mole Ca5(PO4)3F
Now, we can calculate the moles of H3PO4:
14.8 M = 14.8 mol/L
2.00 x 109 gallons * 3.785 L/gallon = 7.57 x 109 L
7.57 x 109 L * 14.8 mol/L = 1.12 x 1011 mol H3PO4
Finally, we can use the ratio to calculate the moles of Ca5(PO4)3F:
1.12 x 1011 mol H3PO4 * (1 mol Ca5(PO4)3F / 3 mol H3PO4) = 3.73 x 1010 mol Ca5(PO4)3F
Since the molar mass of Ca5(PO4)3F is 504.05 g/mol, we can calculate the mass of Ca5(PO4)3F required:
3.73 x 1010 mol * 504.05 g/mol = 1.88 x 1013 g Ca5(PO4)3F
Therefore, approximately 1.88 x 1013 grams of mineral fluoroapatite (Ca5(PO4)3F) would be required each year.
What is the charge on each of the following complex ions? hexaaquairon(II), [Fe(H2O)6]? tris(carbonato)aluminate(III), [Al(CO3)3]? diaquatetrachlorovanadate(III), [V(H2O)2Cl4]? Express the charges numerically, in the order that the complexes are listed, separated by commas. For a nonzero charge, be sure to include the sign (e.g., +1,-2,+3). View Available Hint(s)
Answer:
The charges on the given complexes are: +2, (-3), (-1)
Explanation:
A coordination complex is composed of a central metal atom or metal ion and ligands, bonded by coordinate covalent bonds.
The total charge of the complex is equal to the sum of the charge on central metal and the total charge of the ligands.
1. hexaaquairon(II), [Fe(H₂O)₆]
The oxidation state or charge on the central metal ion, Fe = +2
Charge on the ligand water molecule H₂O = 0
Therefore, the total charge on the complex = +2 + (0 × 6) = +2
2. tris(carbonato)aluminate(III), [Al(CO₃)₃]
The oxidation state or charge on the central metal ion, Al = +3
Charge on the ligand carbonate CO₃²⁻ = (-2)
Therefore, the total charge on the complex = +3 + (-2 × 3) = (-3)
3. diaquatetrachlorovanadate(III), [V(H₂O)₂Cl₄]
The oxidation state or charge on the central metal ion, V = +3
Charge on the ligand water molecule H₂O = 0
Charge on the ligand chloride Cl = (-1)
Therefore, the total charge on the complex = +3 + [(0 × 2)+(-1 × 4)] = +3 + (-4) = (-1)
Therefore, the charge on 1. hexaaquairon(II), [Fe(H₂O)₆] complex is +2
2. tris(carbonato)aluminate(III), [Al(CO₃)₃] complex is (-3)
3. diaquatetrachlorovanadate(III), [V(H₂O)₂Cl₄] complex is (-1)
A chemist prepares repares a solution of magnesium chloride (MgCl2) by measuring out 48. mg of MgCl, into a 300 ml. volumetric flask and filling to the mark with distilled water.
Calculate the molarity of Cl^- anions in the chemist's solution.
Be sure your answer is rounded to 2 significant digits.
Answer:
The molarity of the Cl- anions is 0.0033 M
Explanation:
Step 1: Data given
Mass of MgCl2 = 48 mg = 48 *10^-3 grams
volume = 300 mL = 0.3L
Molar mas of MgCl2 = 95.21 g/mol
Step 2: The balanced equation
MgCl2 → Mg2+ + 2Cl-
This means for 1 mol MgCl2, we'll have 2 moles of Cl-
Step 3: Calculate moles MgCl2
Number of moles of MgCl2 = mass of MgCl2 / Molar mass of MgCl2
Moles MgCl2 = 48*10^-3 grams / 95.21 g/mol
Moles MgCl2 = 5.04 *10-4 moles
Step 4: Calculate moles of Cl-
This means for 1 mol MgCl2, we'll have 2 moles of Cl-
For 5.04 *10-4 moles MgCl2, we will have 2* 5.04 *10-4 moles = 0.001 moles Cl-
Step 5: Calculate molarity of the Cl- anion
Molarity = Moles / volume
Molarity Cl- = 0.001 moles / 0.3 L
Molarity Cl- = 0.0033 M
The molarity of the Cl- anions is 0.0033 M
Write the half-reactions as they occur at each electrode and the net cell reaction for this electrochemical cell containing copper and silver. Cu ( s ) ∣ ∣ Cu 2 + ( aq ) ∥ ∥ Ag + ( aq ) ∣ ∣ Ag ( s ) anode: cathode: net cell reaction:
Answer: The half reactions and net cell reaction of the cell is written below.
Explanation:
The given cell is:
[tex]Cu(s)/Cu^{2+}(aq.)||Ag^{+}(aq.)/Ag(s)[/tex]
Oxidation reaction occurs at anode and reduction reaction occurs at cathode.
Half reactions for the given cell follows:
Oxidation half reaction (anode): [tex]Cu(s)\rightarrow Cu^{2+}(aq.)+2e^-[/tex]
Reduction half reaction (cathode): [tex]Ag^{+}(aq.)+e^-\rightarrow Ag(s)[/tex] ( × 2)
Net cell reaction: [tex]Cu(s)+2Ag^+(aq.)\rightarrow Cu^{2+}(aq.)+2Ag(s)[/tex]
Hence, the half reactions and net cell reaction of the cell is written above.
The half-reactions at each electrode and the net cell reaction for the electrochemical cell containing copper and silver are provided.
Explanation:The half-reactions at each electrode in this electrochemical cell are:
Anode: Cu (s) → Cu2+ (aq) + 2e−
Cathode: 2Ag+ (aq) + 2e− → Ag (s)
The net cell reaction for this electrochemical cell is:
Cu (s) + 2Ag+ (aq) → Cu2+ (aq) + 2Ag (s)
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Which of the following atoms could have an expanded octet when it is the central atom in a covalent compound?a) B
b) O
c) Cl
d) F
Answer:
only chlorine can expand its octet.
Explanation:
An atom can expand its octet is it has empty d orbital
the electronic configuration of given elements will be:
B : 1s2 2s2 2p1 [Valence shell n =2 no d orbital]
O :1s2 2s2 2p4 [Valence shell n =2 no d orbital]
F : 1s2 2s2 2p5 [Valence shell n =2 no d orbital]
Cl :1s2 2s2 2p6 3s2 3p5 3d0 [Valence shell n =2 no d orbital]
Out of given elements only chlorine has empty d orbitals in its valence shell
Thus only chlorine can expand its octet.
A chemist prepares a solution of silver(I) nitrate (AgNO3) by measuring out 269. micromol of silver(I) nitrate into a 300. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mmol/L of the chemist's silver(I) nitrate solution. Be sure your answer has the correct number of significant digits.
Answer:
The concentration of the chemist's silver(I) nitrate solution is 0.897 mmol/L
Explanation:
Step 1: Data given
Number of moles AgNO3 = 269 micromol = 269 * 10^-6 mol
Volume of AgNO3 = 300 mL = 0.3 L
Molar mass of AgNO3 = 169.87 g/mol
Step 2: Calculate molarity of AgNO3
Molarity = number of moles per volume (in Liters)
Molarity AgNO3 = 269 *10^-6 mol / 0.3 L
Molarity AgNO3 = 8.97 * 10^-4 M
8.97 *10^-4 mol/L = 897 micromol/L = 0.897 mmol/L
The concentration of the chemist's silver(I) nitrate solution is 0.897 mmol/L