Answer:
Therewill be produced 170.6 grams NH3, there will remain 25 moles of N2, this is 700 grams
Explanation:
Step 1: Data given
Number of moles hydrogen = 30 moles
Number of moles nitrogen = 30 moles
Yield = 50 %
Molar mass of N2 = 28 g/mol
Molar mass of H2 = 2.02 g/mol
Molar mass of NH3 = 17.03 g/mol
Step 2: The balanced equation
N2 + 3H2 → 2NH3
Step 3: Calculate limiting reactant
For 1 mol of N2, we need 3 moles of H2 to produce 2 moles of NH3
Hydrogen is the limiting reactant.
The 30 moles will be completely be consumed.
N2 is in excess. There will react 30/3 =10 moles
There will remain 30 -10 = 20 moles (this in the case of a 100% yield)
In a 50 % yield, there will remain 20 + 0,5*10 = 25 moles. there will react 5 moles.
Step 4: Calculate moles of NH3
There will be produced, 30/ (3/2) = 20 moles of NH3 (In case of 100% yield)
For a 50% yield there will be produced, 10 moles of NH3
Step 5: Calculate the mass of NH3
Mass of NH3 = mol NH3 * Molar mass NH3
Mass of NH3 = 20 moles * 17.03
Mass of NH3 = 340.6 grams = theoretical yield ( 100% yield)
Step 6: Calculate actual mass
50% yield = actual mass / theoretical mass
actual mass = 0.5 * 340.6
actual mass = 170.3 grams
Step 7: The mass of nitrogen remaining
There remain 20 moles of nitrogen + 50% of 10 moles = 25 moles remain
Mass of nitrogen = 25 moles * 28 g/mol
Mass of nitrogen = 700 grams
Answer:
25 moles
Explanation:
1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia. 30 moles of hydrogen will react with 10 moles of nitrogen to give 20 moles of ammonia. As the actual yield is 50%, ammonia formed is 10 moles, the amount of nitrogen reacted is 5 moles, and the amount of hydrogen reacted is 15 moles. The mass of the remaining hydrogen is 15 moles and of the remaining nitrogen is 25 moles.
Which pair of samples contains the same number of oxygen atoms in each compound?0.20 mol Ba(OH)2 and 0.20 mol H2SO40.20 mol Br2O and 0.20 mol HBrO0.10 mol Fe2O3 and 0.50 mol BaO0.10 mol Na2O and 0.10 mol Na2SO4
Answer:
0.20 mol Br2O and 0.20 mol HBrO have the same number of oxygen atoms
Explanation:
0.20 mol Ba(OH)2 and 0.20 mol H2SO4
In Ba(OH)2 there are 2 moles of O atoms in every mol of Ba(OH)2.
Number of O atoms in 0.20 moles Ba(OH)2 = 2*0.20 = 0.40 moles O atom
In H2SO4 there are 4 moles of O atoms for every mol of H2SO4.
Number of O atoms in 0.20 moles H2SO4 = 4*0.20 = 0.80 moles O atom
⇒ 0.20 mol Ba(OH)2 and 0.20 mol H2SO4 do not have the same number of oxygen atoms.
0.20 mol Br2O and 0.20 mol HBrO
In Br2O there is 1 mol of O atoms in every mol Br2O
Number of O atoms in 0.20 moles Br2O = 0.20*1 = 0.20 moles O atom
In HBrO there is 1 mol of O atom in every mol HBrO
Number of O atoms in 0.20 moles HBrO = 0.20 *1 = 0.20 moles O atom
⇒ in 0.20 moles Br2O and 0.20 moles HBrO we have the same number of oxygen atoms
0.20 moles of Oygen contains: = 0.20 * 6.022*10^23 = 1.2 *10^23 O atoms
0.10 mol Fe2O3 and 0.50 mol BaO
In Fe2O3 there are 3 moles of O atoms in every mol of Fe2O3
Number of O atoms in 0.10 moles Fe2O3 = 0.10 * 3 = 0.30 moles O atom
In BaO there is 1 mol of O atoms in every mol BaO
Number of O atoms in 0.50 mol BaO = 1*0.50 = 0.50 moles O atom
⇒ 0.10 mol Fe2O3 and 0.50 mol BaO do not have the same number of oxygen atoms.
0.10 mol Na2O and 0.10 mol Na2SO4
In Na2O there is 1 mol of O atoms in every mol of Na2O
Number of O atoms in 0.10 mol Na2O = 1*0.10 = 0.10 moles O atom
In Na2sO4 there are 4 moles of O atoms in every mol of Na2SO4
Number of O atoms in 0.10 mol Na2SO4 = 4*0.10 = 0.40 moles O atom
⇒ 0.10 mol Na2O and 0.10 mol Na2SO4 do not have the same number of oxygen atoms.
The pair of samples that contains the same number of oxygen atoms in each compound is 0.20 mol H2SO4 and 0.20 mol HBrO.
Explanation:To determine which pair of samples contains the same number of oxygen atoms in each compound, we need to calculate the number of oxygen atoms in each sample.
0.20 mol Ba(OH)2 contains 2 oxygen atoms since each Ba(OH)2 molecule has 2 hydroxide groups, and each hydroxide group has 1 oxygen atom.0.20 mol H2SO4 contains 4 oxygen atoms since each H2SO4 molecule has 4 oxygen atoms.0.20 mol Br2O contains 1 oxygen atom since each Br2O molecule has 1 oxygen atom.0.20 mol HBrO contains 2 oxygen atoms since each HBrO molecule has 2 oxygen atoms.Therefore, the pair of samples that contains the same number of oxygen atoms in each compound is 0.20 mol H2SO4 and 0.20 mol HBrO.
A silver nitrate, AgNO3, solution of unknown concentration was discovered in the lab. To determine the concentration of the solution, a concentration cell was set up with the unknown solution in the anode compartment and a 1.0 M AgNO3 solution in the cathode compartment. The cell had a potential (E) of +0.045 V at 25°C. What is the concentration of silver in the unknown solution?
Final answer:
The concentration of silver in the unknown solution can be determined using the Nernst equation with the given cell potential of +0.045 V. By rearranging and substituting known values into the Nernst equation, we can calculate the unknown silver ion concentration at the anode.
Explanation:
To determine the concentration of silver in the unknown AgNO3 solution using a concentration cell, we can apply the Nernst equation. The reaction in a concentration cell is Ag+ (aq) → Ag+ (aq), which proceeds with a transfer of electrons from one compartment to the other. Since there is a potential difference (E) of +0.045 V, we can calculate the unknown concentration at the anode using the Nernst equation:
E = E°_cell - (RT/nF) ln(Q)
Where:
E is the cell potentialE°_cell is the standard cell potential, which is 0 V in concentration cellsR is the gas constant (8.314 J/(mol·K))T is the temperature in Kelvin (298 K)n is the number of electrons transferred per mole of reaction (1 for silver)F is the Faraday constant (96485 C/mol)Q is the reaction quotient, which is equal to [Ag+] anode / [Ag+] cathodeRearranging the Nernst equation and solving for Q will provide us the ratio of the Ag+ concentration in the anode to that in the cathode. By substituting the measured E value, R, T, n, and F into the Nernst equation and knowing that [Ag+] cathode is 1.0 M, we can solve for the unknown [Ag+] anode concentration. Finally, by taking the anti-logarithm of the result, we can find the concentration of silver in the unknown solution.
Sodium metal reacts with water to produce hydrogen gas according to the following equation: 2Na(s) + 2H2O(l)2NaOH(aq) + H2(g) The product gas, H2, is collected over water at a temperature of 20 °C and a pressure of 754 mm Hg. If the wet H2 gas formed occupies a volume of 8.77 L, the number of moles of Na reacted was mol. The vapor pressure of water is 17.5 mm Hg at 20 °C.
Answer:
Number of moles of sodium reacted = 0.707 moles
Explanation:
P(H₂) = P(T) – P(H₂O)
P(H₂) = 754 – 17.5 = 736.5 mm Hg
Use the ideal gas equation which
PV= nRT, where P is the pressure V is the volume, n is the number of moles R is the Gas Constant and T is temperature
Re- arrange to calculate the number of moles and using the data provided
n = P x V/R x T
n =736.5 x 8.77/62.36367 x (mmHg/mol K) x (20 + 273)
n = 0.35348668
n = 0.353 moles H₂
from the equation we know that
0.353 mole H₂ x 2mole Na/1mole H₂, So
0.353 x 2 = 0.707 mole Na
The number of moles of Sodium metal reacted were 0.707 moles.
0.708 moles of Na react with water to produce 8.77 L of H₂ collected over water at 20 °C and 754 mmHg.
Sodium metal reacts with water to produce hydrogen gas according to the following equation:
2 Na(s) + 2 H₂O(l) ⇒ 2 NaOH(aq) + H₂(g)
Hydrogen is collected over water. The total pressure of the gaseous mixture is 754 mmHg. If the vapor pressure of water is 17.5 mmHg, the partial pressure of hydrogen is:
[tex]P = pH_2 + pH_2O\\\\pH_2 = P - pH_2O = 754 mmHg - 17.5 mmHg = 737 mmHg[/tex]
Then, we will convert 20 °C to Kelvin using the following expression.
[tex]K = \° C + 273.15 = 20\° C + 273.15 = 293 K[/tex]
Hydrogen occupies 8.77 L at 293 K and 737 mmHg. We can calculate the moles of hydrogen using the ideal gas equation.
[tex]P \times V = n \times R \times T\\\\n = \frac{P \times V}{ R \times T} = \frac{737mmHg \times 8.77L}{ (62.4mmHg/mol.K) \times 293K} = 0.354 mol[/tex]
The molar ratio of Na to H₂ is 2:1. The moles of Na that produced 0.354 moles of H₂ are:
[tex]0.354 mol H_2 \times \frac{2molNa}{1molH_2} = 0.708 mol Na[/tex]
0.708 moles of Na react with water to produce 8.77 L of H₂ collected over water at 20 °C and 754 mmHg.
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One mole of an ideal gas is compressed isothermally but irreversibly at 130oC from 2.5 bar to 6.5bar in a piston/cylinder device. The work required is 30% greater than the work of reversible, isothermal compression. The heat transferred from the gas during compression flows to a heat reservoir at 25oC. Claculate the entropy changes of the gas, the heat reservoir, and ΔStotal.
Answer:
Entropy change of gas = -7.944 J/mol*K
Entropy change of the reservoir = 13.96 J/mol*K
Total entropy change = 6.02 J/mol*K
Explanation:
Step 1: Data given
1 mol of ideal gas is compressed isothermally ( = constant temperature)
Temperature : 130 °C
Pressure = 2.6 bar to 6.5 bar
The work required is 30% greater than the work of reversible
The heat transferred from the gas during compression flows to a heat reservoir at 25°C
Step 2: Calculate entropy change for gas
ΔSgas = Cp*ln(T2/T1) - R*ln (P2/P1)
⇒ Since the temperature is constant, T2 = T1 so ln(T2/T1) = 0
ΔSgas = - R*ln (P2/P1)
⇒ with R = gas constant = 8.314
⇒ with P1 = initial pressure = 2.5 barr
⇒ with P2 = final pressure = 6.5 bar
ΔSgas = -8.314 *ln(6.5/2.5)
ΔSgas = -7.944 J/mol*K
Step 3: Calculate reversible work done
Reversible work done = R*T*ln (P2/P1)
Reversible work done = 8.314 * 403.15 * ln (6.5/2.5)
Reversible work done = = 3202. 67 J/mol
Step 4: Actual work done
Actual work done = 1.3 * 3202.67 = 4163.47 J/mol
For isothermal compression:
Q = -W
Q = -4163.47 J/mol
Step 5: Calculate entropy change for reservoir
Entropy change for reservoir ΔSres = -Q/Tres = 4163.47 /298.15
ΔSres = 13.96 J/mol*K
Step 6: Calculate total entropy change
ΔStotal = ΔSgas + ΔSres = -7.944 J/mol*K +13.96 J/mol*K
ΔStotal = 6.02 J/mol*K
The entropy change of the gas is 6.02 J/mol.
How to calculate entropy?Firstly, the entropy change for gas will be:
= 1 × 8.314 × In(2.5/6.5)
= -7.944 J/K
The reversible work done will be:
= 8.314 × 403.15 × In(6.5/2.5)
= 3202.67 J/mol
The actual work done will be:
= 1.3 × 3202.67
= 4163.47 J/mol
The entropy change for reservoir will be:
= -7.944 + 13.96
= 6.02 J/mol
In conclusion, the entropy change is 6.02 J/mol
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If 44.5 mL of 0.0989M sodium hydroxide solution is needed to titrate the amount of acetic acid in a 5.00 mL sample of vinegar, what is the weight/weight percent (w/w %) of acetic acid in the vinegar.
(MM acetic acid = 60.04 g) Do not include units in your answer. Use the correct number of significant figures.
Answer:
5.28 %
Explanation:
To solve this problem we are going to calculate the moles of NaOH required to titrate the vinegar. Since this reaction is one mole NaOH to 1 mol acetic acid we will have the moles of acetic acid present in the 5 mL sample . By multiplying the number of moles of acetic acid by its molecular weight we obtain the grams of acid.
Now since we are being asked the w/w % we need the weight of solution which is not given in the problem. However we can assume that its value will be close to that of pure water and give it the value of 5 g since the density of water is one g/mL.
moles NaOH = 44.5 mL x 1L/1000 mL x 0.098 mol/L = 0.00440
mol acetic acid = 0.00440
mass acetic acid = 0.00440 mol x 60.04 g/mol = 0.264 g acetic acid
percent (w/w) = (0.264 g/ 5 g ) x 100 = 5.28 %
Thermal decomposition of a rail car load of limestone to lime and carbon dioxide requires 2.97 x 106 kJ of heat.
Convert this energy to calories.
Once you have the value, determine its log (base 10).
Answer: a) [tex]68.3\times 10^6cal[/tex]
b) [tex]log_{10}(68.3\times 10^6cal)=7.83[/tex]
Explanation:
Heat is defined as a spontaneous flow of energy from one object to another. It is measured in Joules, calories, kilo Joules etc.
These units of energy are inter convertible.
We are given:
a) Energy absorbed by limestone = [tex]2.97\times 10^6kJ[/tex]
Converting this unit of temperature into [tex]calories[/tex] by using conversion factor:
1 kJ = 239.006 calories
[tex]2.97\times 10^6kJ=\frac{239.006}{1}\times 2.97\times 10^6=68.3\times 10^6cal[/tex]
Thus the energy in calories is [tex]68.3\times 10^6cal[/tex]
b) The value of log base 10 of [tex]68.3\times 10^6cal[/tex] is:
[tex]log_{10}(68.3\times 10^6cal)=7.83[/tex]
In the laboratory a student determines the specific heat of a metal. He heats 19.5 grams of copper to 98.27 °C and then drops it into an insulated cup containing 76.3 grams of water at 24.05 °C. When thermal equilibrium is reached, he measures the final temperature to be 25.69 °C. Assuming that all of the heat is transferred to the water, he calculates the specific heat of copper to be__________ J/g°C.
Answer:
The specific heat of copper is 0.37 J/g°C
Explanation:
Step 1: Data given
Mass of copper = 19.5 grams
Initial temperature of copper = 98.27 °C
Mass of water = 76.3 grams
Initial temperature of water = 24.05 °C
Final temperature of water and copper = 25.69 °C
Step 2: Calculate specific heat of copper
Qgained = -Qlost
Q = m*c*ΔT
Qwater = -Qcopper
m(water) * c(water) * ΔT(water) = - m(copper) * c(copper) *ΔT(copper)
⇒ with m(water) = 76.3 grams
⇒ with c(water) = 4.184 J/g°C
⇒ with ΔT(water) = T2-T1 = 25.69 - 24.05 = 1.64
⇒ with m(copper) = 19.5 grams
⇒ with c(copper) = TO BE DETERMINED
⇒ with ΔT(copper) = T2-T1 = 25.69 - 98.27 = -72.58
76.3 * 4.184 * 1.64 = - 19.5 * c(copper) * -72.58
523.552 = 1415.31 * c(copper)
c(copper) = 0.37 J/g°C
The specific heat of copper is 0.37 J/g°C
Given only the following data, what can be said about the following reaction?
3H2(g) + N2(g)---> 2NH3(g) ΔH=-92kJ
A.) The enthalpy of products is greater than the enthalpy of reactants
B.) The total bond energies of products are greater than the total bond energies of reactants
C.) The reaction is very fast
D.) Nitrogen and Hydrogen are very stable bonds compared to the bonds of ammonia
Answer:
The correct answer is B the total bond energies of the product is greater than the total bond energies of the reactants.
Explanation:
3H2+N2=2NH3
This reaction is an endothermic reaction that means that reaction consume heat energy.
Due the above reaction is endothermic the enthalpy change of the reaction is negative(-ve).
During endothermic reaction the total bond energies of the product is greater than the total bond energies of the reactants.
Write a net ionic equation to show how triethylamine, (C2H5)3N, behaves as a base in water. The substance 2-methylpiperidine is a weak nitrogenous base like ammonia. Complete the following equation that shows how 2-methylpiperidine reacts when dissolved in water.
You may find bellow the net ionic equations.
Explanation:
Net ionic equation of triethylamine in water:
(C₂H₅)₃N (l) + H₂O (l) → (C₂H₅)₃NH⁺ (aq) + OH⁻ (aq)
where:
(l) - liquid
(aq) - aqueous
You may find in the attached picture the ionization of 2-methylpiperidine in water.
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Triethylamine and 2-methylpiperidine act as weak bases in water, accepting protons to form hydroxide ions and their respective conjugate acids. This is an example of base ionization. It was not possible to provide an exact equation for 2-methylpiperidine without a specific structure.
Explanation:When triethylamine, also a weak nitrogen base like ammonia, is dissolved in water, it accepts a proton from a water molecule to form a hydroxide ion (OH-) and an ethylammonium ion ((C2H5)3NH+). This is represented by the equation: (C2H5)3N(aq) + H2O(l) ⇌ (C2H5)3NH+(aq) + OH-(aq).
Similarly, 2-methylpiperidine being a weak base, will also react with water to form hydroxide ions (OH-) and 2-methylpiperidinium ions. However, without a specific structure for 2-methylpiperdine, it's challenging to write the exact equation.
These are examples of base ionization, where a base reacts with water to produce hydroxide ions and a conjugate acid. Both triethylamine and 2-methylpiperidine act as Brønsted bases, accepting protons from water molecules.
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A 250 mL container of CO2 exerting a pressure of 1.00 atm is connected through a valve to a 500 mL container of O2 exerting a pressure of 2.00 atm.
When the valve is opened, the gases mix, forming a 750 mL mixture of CO2 and O2.
What is the total pressure of this mixture?
Explanation:
The given data is as follows.
[tex]P_{1}[/tex] = 1 atm, [tex]P_{2}[/tex] = 2 atm
[tex]V_{1}[/tex] = 250 ml, [tex]V_{2}[/tex] = 500 ml
Total volume = [tex]V_{1} + V_{2}[/tex] = 750 ml
Therefore, total pressure will be as follows.
[tex]P_{total} V_{total} = P_{1}V_{1} + P_{2}V_{2}[/tex]
[tex]P_{total} = \frac{P_{1}V_{1} + P_{2}V_{2}}{V_{total}}[/tex]
= [tex]\frac{1 atm \times 250 ml + 2 atm \times 500 ml}{750 ml}[/tex]
= 1.66 atm
Thus, we can conclude that total pressure of the given mixture is 1.66 atm.
Which statement is false?
O For the complete conversion of glucose to CO2, approximately 32 ATP molecules can be synthesized.
O The PDH complex is considered to be a reaction of the citric acid cycle.
O Succinate dehydrogenase is an integral membrane protein.
O Succinyl–CoA synthetase and succinic thiokinase are two names for the same enzyme.
Answer:
"The PDH complex is considered to be a reaction of the citric acid cycle" is the false statement
Explanation:
The PDH complex is involved in the oxidation of piruvate, producing acetate and free CO2 (besides ATP and NADH). Concomitantly, in presence of coenzyme A, it binds the acetate molecule to form Acetyl-CoA.
Acetyl-CoA, later, will enter the Krebs cycle reacting with oxalacetate to form citric acid.
The other statements options are true
Calculate the molar solubility of Cd(OH)2 when buffered at a pH = 12.30. The Ksp for Cd(OH)2 is 2.5 x 10-14. Calculate the molar solubility of Cd(OH)2 when buffered at a pH = 12.30. The Ksp for Cd(OH)2 is
a.2.5 x 10-14 M.
b. 8.5 x 10-6 M
c. 6.3 x 10-11 M
d. 1.3 x 10-12 M
e. 5.0 x 10-2 M
f. 1.8 x 10-5 M
Answer:
c. 6,3x10⁻¹¹M
Explanation:
The solubility of a buffer is defined as the concentration of the dissolved solid in a saturated solution. For the Cd(OH)₂, solubility is:
[Cd²⁺] = S
The dissolution of Cd(OH)₂ is:
Cd(OH)₂ ⇄ Cd²⁺ + 2OH⁻
And the ksp is defined as:
ksp = [Cd²⁺][OH⁻]²
As ksp = 2,5x10⁻¹⁴ and [OH⁻] at pH=12,30 = 10^-(14-12,30) = 0,01995M
2,5x10⁻¹⁴ = [Cd²⁺]×(0,01995M)²
[Cd²⁺] = 6,3x10⁻¹¹M
That means solubility is c. 6,3x10⁻¹¹M
I hope it helps!
The molar solubility of Cd(OH)2 when buffered at a pH of 12.30 can be calculated using the concept of hydrolysis. The correct answer is 6.3 x 10^(-11) M.
Explanation:To calculate the molar solubility of Cd(OH)2 when buffered at a pH of 12.30, we need to use the concept of hydrolysis. Cd(OH)2 is a slightly soluble salt that undergoes hydrolysis in aqueous solution. At a high pH value, OH- ions react with water to form more OH- ions, shifting the equilibrium towards the hydrolysis reaction.
First, we write the balanced equation for the hydrolysis reaction: Cd(OH)2(s) ⇌ Cd2+(aq) + 2OH-(aq)Since OH- is being produced, we can assume that the concentration of OH- is much greater than that of Cd2+. Therefore, we can ignore the concentration of Cd2+ when calculating the solubility product (Ksp).Next, we use the equation for the hydrolysis reaction to write the expression for the solubility product constant (Ksp): Ksp = [Cd2+][OH-]^2The concentration of OH- ions in a basic solution is related to the pH by the equation: pOH = 14 - pHUsing this equation, we can calculate the pOH of the buffered solution: pOH = 14 - 12.30 = 1.70Then, we convert the pOH back to OH- concentration: [OH-] = 10^(-pOH) = 10^(-1.70)Finally, we substitute the calculated [OH-] into the expression for Ksp to solve for the molar solubility of Cd(OH)2: [Cd(OH)2] = sqrt(Ksp / [OH-]^2)After performing the calculations, the molar solubility of Cd(OH)2 when buffered at a pH of 12.30 is approximately 6.3 x 10^(-11) M. Therefore, the correct answer is option c. 6.3 x 10^(-11) M.
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A 75.0 mL 75.0 mL aliquot of a 1.70 M 1.70 M solution is diluted to a total volume of 278 mL. 278 mL. A 139 mL 139 mL portion of that solution is diluted by adding 165 mL 165 mL of water. What is the final concentration? Assume the volumes are additive.
Answer:
0.210 M
Explanation:
A 75.0 mL aliquot of a 1.70 M solution is diluted to a total volume of 278 mL.
In order to find out the resulting concentration (C₂) we will use the dilution rule.
C₁ × V₁ = C₂ × V₂
1.70 M × 75.0 mL = C₂ × 278 mL
C₂ = 0.459 M
A 139 mL portion of that solution is diluted by adding 165 mL of water. What is the final concentration? Assume the volumes are additive.
Since the volumes are additive, the final volume V₂ is 139 mL + 165 mL = 304 mL. Next, we can use the dilution rule.
C₁ × V₁ = C₂ × V₂
0.459 M × 139 mL = C₂ × 304 mL
C₂ = 0.210 M
Answer:
The correct answer is 0.21 M
Explanation:
We have an initial solution of concentration 1.70 M and we dilute it twice. In each dilution we can calculate the final concentration (Cf) from the initial concentration (Ci) and the final and initial volumes respectively (Vf and Vi) as follows:
Cf x Vf= Ci x Vi
Cf= Ci x Vi/ Vf
In the first dilution, Ci is 1.70 M, the initial volume we take is 75 ml and the final volume is 278 ml.
Cf= 1.70 M x 75 ml / 278 ml = 0.46 M
In the second dilution, the initial concentration is the previously obtained (Ci= 0.46 M), the initial volume is Vi= 139 ml and the final volume is the addition of 139 ml and 165 ml (because we add 165 ml to 139 ml). Thus:
Cf= (0.46 M x 139 ml)/ (139 ml + 165 ml) = 0.21 M
The synthesis of CH3OH from CO and H2 is represented by the equation below.
CO + 2 H2 ---> CH3OH ΔH < 0
Which of the following statements is true about the bond energies in this reaction?
The energy absorbed as the bonds in the reactants is broken is greater than the energy released as the bonds in the products are formed.
The energy released as the bonds in the reactants is broken is greater than the energy absorbed as the bonds in the products are formed.
The energy released as the bonds in the reactants is broken is less than the energy absorbed as the bonds in the products are formed.
The energy absorbed as the bonds in the reactants is broken is less than the energy released as the bonds in the products are formed.
The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the products are formed. This is indicative of an exothermic reaction.
Explanation:In the given reaction, CO + 2 H2 ---> CH3OH ΔH < 0, this is an exothermic reaction as indicated by the negative delta H value. The negative ΔH value signifies that the total energy released when the new bonds are formed in the product (CH3OH) is more than the total energy absorbed to break the bonds in the reactants (CO and H2).
Therefore, the correct statement is: The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the products are formed.
This corresponds to the fact that in an exothermic reaction, the products are at a lower energy level than the reactants, therefore, energy is released in the reaction.
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The correct statement is that the energy absorbed as the bonds in the reactants is broken is less than the energy released as the bonds in the products are formed, indicating an exothermic reaction.
The correct statement is: The energy absorbed as the bonds in the reactants is broken is less than the energy released as the bonds in the products are formed.
In this specific reaction, energy is required to break a C-O triple bond and two H-H single bonds in the reactants. Energy is then released as three C-H single bonds, a C-O single bond, and an O-H single bond are formed in the product, CH₃OH.
Since ΔH is negative, it indicates that the total energy released in bond formation is greater than the total energy absorbed in bond breaking, reaffirming that the reaction is exothermic.
Calculate the lattice energy for CaCl2 from the following information: Energy needed to vaporize one mole of Ca(s) is 192kJ. For calcium the first ionization energy is 589.5kJ/mol and the second ionization energy is 1146kJ/mol. The electron affinity of Cl is-348kJ/mol. The bond energy of Cl2 is 242.6kJ/mol of CI-Cl bonds. The standard heat of formation of CaCl2 is -795kJ/mol. (include the sign and your numerical answer, do not include units, do not use scientific notation, and round your answer to 1 decimal point)
Calculate the total energy for individual process, including energy to vaporize Ca(s), first and second ionization energies of Ca, bond energy of Cl2 and electron affinity of Cl. The lattice energy is the result of subtracting standard heat of formation of CaCl2 from the total energy calculated, which equals to 2635.9 kJ.
Explanation:The lattice energy for CaCl2 can be calculated using the given information and by understanding that the process of forming a salt like CaCl2 involves several different energies. First, there is the energy required to vaporize Ca(s), then the energy for first and second ionization of the calcium atom, followed by the electron affinity for Cl and the bond energy of Cl2.
To start calculating, first add the energy to vaporize Ca(s), the first and second ionization energies for Ca: 192kJ + 589.5kJ + 1146kJ = 1927.5kJ. When 2 Cl react with Ca, this process includes the bond energy for Cl2 and twice the electron energy for Cl: 242.6kJ + 2 * -348kJ = -453.4kJ. To calculate the energy required to form lattice, subtract the standard heat of formation of CaCl2 from the total energy calculated: 1927.5kJ - (-453.4kJ + -795kJ) = 2635.9 kJ
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A galvanic (voltaic) cell has the generic metals X and Y as electrodes. X is more reactive than Y , that is, X more readily reacts to form a cation than Y does. Classify the descriptions by whether they apply to the X or Y electrode.
(a) anode
(b) cathode
(c) electrons in the wire flow toward
(d) electrons in the wire flow away
(e) cations from salt bridge flow toward
Answer:
(a) X electrode
(b) Y electrode
(c) Y electrode
(d) X electrode
(e) Y electrode
Explanation:
A galvanic (voltaic) cell has the generic metals X and Y as electrodes. X is more reactive than Y, that is, X more readily reacts to form a cation than Y does.
In the X electrode occurs the oxidation whereas in the Y electrode occurs the reduction.
Oxidation: X(s) → X⁺ⁿ(aq) + n e⁻
Reduction: Y⁺ˣ(aq) + x e⁻ → Y(s)
Classify the descriptions by whether they apply to the X or Y electrode.
(a) anode. Is where the oxidation takes place (X electrode).
(b) cathode. Is where the reduction takes place (Y electrode).
(c) electrons in the wire flow toward. Electrons in the wire flow toward the cathode (Y electrode).
(d) electrons in the wire flow away. Electrons in the wire flow away from the anode (X electrode).
(e) cations from salt bridge flow toward. Cations from the salt bridge flow toward the cathode (Y electrode) to maintain the electroneutrality.
In a galvanic cell, the more reactive metal X is the anode where electrons flow away from, and the less reactive metal Y is the cathode where electrons flow toward. Cations from the salt bridge migrate toward the anode, maintaining electrical neutrality.
Explanation:In a galvanic (voltaic) cell, the generic metal X is more reactive than Y, indicating that X acts as the anode where oxidation takes place, and Y acts as the cathode where reduction occurs. The characteristics of the electrodes in a voltaic cell are as follows:
(a) Anode - X electrode since it is more reactive and readily oxidized.(b) Cathode - Y electrode since it is less reactive and reduction occurs here.(c) Electrons in the wire flow toward the Y electrode (cathode).(d) Electrons in the wire flow away from the X electrode (anode).(e) Cations from the salt bridge flow toward the X electrode (anode) because it is the site of oxidation.These characteristics are essential to the proper functioning of the galvanic cell, ensuring the flow of electrons from the anode to the cathode, and allowing the cell to generate electricity through spontaneous redox reactions.
Which statement about intermolecular forces is true?
Group of answer choices
A. Only occur in ionic bonds.
B. They have to be overcome to decompose a substance.
C. These forces hold atoms together in a molecule.
D. They are responsible for the physical properties of matter.
Intramolecular forces describe those forces that are found within the molecules and are shared by the electronic bonds. They hold the atoms and molecules together.
They are responsible for the holding of atoms together in a single molecule. Thus they also include electromagnetic forces of attraction and repulsion.Hence the option C is correct.
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. If the following mixtures of two compounds are being separated by gas chromatography, which one of the compounds would be expected to elute from the column first (have the shortest retention time)? Consider boiling points that are only I or 2°C apart to be essentially identical. Consider compounds with the same functional groups to be identical in polarity if they differ by no more than a few carbons. Look up any necessary structures. Mixture Compound with the shortest retention time Polarity of the column packing a. ethyl acetate (bp 77°C) and ethyl butyrate (bp 120°C) polar nonpolar b, ethyl acetate (bp 77"C) and ethyl butyrate (bp 120°C) c. acetic acid (bp l 18°C) and n-butyl alcohol (bp 117c) polar d. sec-butyl alcohol (bp 100"C) nonpolar and ethyl propionate (bp 99c)
Answer:
a. Ethyl acetate.
b. Ethyl acetate.
c. N-butyl alcohol.
d. Sec-butyl alcohol.
Explanation:
In gas chromatography, the elution order depends of boiling point and polarity of compounds. The lower boiling point will elute first and the elution depends of kind of column you are using; if column is polar, non-polar compounds will elute first and vice versa.
a. ethyl acetate (bp 77°C) and ethyl butyrate (bp 120°C) polar:
As the structures of these two molecules just change in 2 carbons it is possible to consider that are the same polarity. Thus, we will see just boiling point, as ethyl acetate has lower boiling point will elute first.
b. ethyl acetate (bp 77°C) and ethyl butyrate (bp 120°C) nonpolar
Again, we will consider the same polarity for both compunds and ethyl acetate will elute first because its boiling point
c. acetic acid (bp 118°C) and n-butyl alcohol (bp 117c) polar.
As boiling point are similar we will see polarity: Acetic acid is a carboxilic acid and n-butyl alcohol has just a OH group in tis structure, that means acetic acid is more polar. As column is polar, acetic acid will be more retained doing n-butyl alcohol elutes first.
d. sec-butyl alcohol (bp 100"C) and ethyl propionate (bp 99c) nonpolar
As boiling point are similar we will see polarity: Sec-butyl alcohol has just a OH group but ethyl propionate is an esther, that means sec-butyl alcohol is more polar. As column is nonpolar, the polar compound will elute first, that is sec-butyl alcohol.
i hope it helps!
In gas chromatography, a compound with a lower boiling point tends to elute first from the column. Ethyl acetate, due to its lower boiling point, would elute first in both nonpolar and polar column conditions for mixtures a and b. For mixtures c and d, acetic acid and sec-butyl alcohol may elute first, though factors such as polarity may play a role in the precise order.
Explanation:Order of Elution in Gas Chromatography
In gas chromatography, the compound that elutes first is generally the one with the lower boiling point and weaker intermolecular forces, since it interacts less strongly with the stationary phase and hence moves faster through the column.
For mixture a with a nonpolar column packing, ethyl acetate (bp 77°C) should elute first due to its lower boiling point compared to ethyl butyrate (bp 120°C).For mixture b with a polar column packing, the compound with the shortest retention time would still be ethyl acetate because the boiling points are more decisive in this context.For mixture c, acetic acid and n-butyl alcohol have nearly identical boiling points, so other factors such as the difference in polarity might influence their elution order. However, if their polarities are similar here, the order may still depend on subtle differences in boiling points or interactions with the polar column.For mixture d, with a nonpolar column, sec-butyl alcohol (bp 100°C) would be expected to elute slightly before ethyl propionate (bp 99°C) due to the slightly higher boiling point suggesting stronger interactions with the stationary phase.The conclusion for each mixture takes into account boiling points as a primary factor, with polarity as a secondary factor when boiling points are comparable.
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The balanced equation for the reaction of ammonia and oxygen is the following. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) The standard molar entropies for the products and reactants are listed below. Calculate the change in standard molar entropy for this reaction at 298.0 K and standard pressure, in J/mol·K. (Enter your answer to the tenths place. Include the sign of the value in your answer.)
Answer:
ΔS° = 180.5 J/mol.K
Explanation:
Let's consider the following reaction.
4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)
The standard molar entropy of the reaction (ΔS°) can be calculated using the following expression.
ΔS° = ∑np × S°p - ∑nr × S°r
where,
ni are the moles of reactants and products
S°i are the standard molar entropies of reactants and products
ΔS° = 4 mol × S°(NO(g)) + 6 × S°(H₂O(g)) - 4 mol × S°(NH₃(g)) - 5 mol × S°(O₂(g))
ΔS° = 4 mol × 210.8 J/K.mol + 6 × 188.8 j/K.mol - 4 mol × 192.5 J/K.mol - 5 mol × 205.1 J/K.mol
ΔS° = 180.5 J/K
This is the change in the entropy per mole of reaction.
Final answer:
The question requests the calculation of the change in standard molar entropy for a specific chemical reaction, but specific entropy values are not provided, making it impossible to complete the calculation as asked.
Explanation:
The question asks to calculate the change in standard molar entropy (ΔS°) for the reaction of ammonia (NH3) and oxygen (O2) to form nitrogen monoxide (NO) and water (H2O) at 298.0 K and standard pressure. The formula to use is ΔS° = ∑S°(products) - ∑S°(reactants). Unfortunately, the standard molar entropies (S°) for the reactants and products are not provided in the question. Normally, these values would be found in a standard thermodynamic table. Once you have these values, you would multiply the entropy of each substance by its coefficient in the balanced equation, sum these values for both reactants and products, and then subtract the sum for reactants from the sum for products. This will give you the change in entropy for the reaction.
The slowest step of a reaction mechanism is called the
A.) Elementary Step
B.) Inhibitor
C.) Rate Law
D.) Rate-Determining Step
Answer:
D.) Rate-Determining Step
Explanation:
Rate - Determining Step -
The slowest step of any of the chemical reaction helps to find the overall rate of the chemical reaction , and , hence is known as the rate - determining step .
There are two type of reaction possible , one is elementary reaction and a complex reaction .
Elementary reaction is a single step reaction , and hence , that very step determined the rate of the reaction and hence is known as the rate determining step .
And ,
In case of a complex reaction , the reaction is preceded by many steps , and hence , the slowest step among other steps is known as the rate determining step of the reaction .
Marianne gets dressed and puts on some of her favorite perfume. While applying the perfume, she accidentally gets some in her mouth and notices that it has abitter taste. After getting dressed, she heads to the kitchen to prepare some breakfast. She fills a small bowl with plain yogurt and takes a taste. The yogurt is too sour for her liking, so she adds honey to it for some sweetness. When she is done eating, she washes her bowl with soap and water. The soap is so slippery that she accidentally drops the bowl while cleaning it, causing it to break on the kitchen floor. Frustrated, Marianne sweeps up the broken glass and puts it in the trash, and then heads to work. Which substance displays a characteristic of an acid? A:soap B:yogurt C:perfume D:honey
Answer:
Yogurt displays characteristics of an acid.
Explanation:
The characteristics of an Acid are as follows:
It has an pH of less than 7It has a sour aftertaste(though one shouldn't try it)It increases the [tex]H^{+}[/tex] concentration of water.It reacts with Metals to liberate Hydrogen Gas.It gives out [tex]H^{+}[/tex] ions in aqueous solution.It turns blue litmus to red.Only Yogurt displays one of these properties ie. sour taste, therefore it is the only material having characteristic of acid.
Bittery taste and slippery touch are characteristics of bases.
Answer:
its c
Explanation:
The spectrum of a hydrogen atom contains a total of 26 lines, and that of lithium possess approximately eight times as many. This provides evidence for the quantum mechanical model of the atom due to
larger mass of the lithium atom.
greater number of lithium isotopes.
greater attraction between the electrons and the lithium nucleus.
greater number of occupied sublevels in the lithium atom
Answer:
greater number of occupied sublevels in the lithium atom
Explanation:
Although Hydrogen has only one electron, the atom has several different energy levels. When the electron transitions from a higher energy level to a lower one, photons are released. The photons absorb light at different wavelengths and colors.then they appear as lines on the spectrum of the hydrogen atom. Lithium has a greater number of occupied sub-levels which means more electrons will transition through the energy levels leading to more lines appearing on its spectrum .
For which of the following reactions will the reactant experience the largest degree of decomposition
upon reaching equilibrium at 500 K?
A) 2NO2F(g)--> 2NO2(g) + F2(g); Kp = 6.6 10-22
B) 2SO3(g)--> 2SO2(g) + O2(g); Kp = 1.3 10-5
C) 2NOF(g)--> 2NO(g) + F2(g); Kp = 1.2 10-26
D) 2NOCl(g)--> 2NO(g) + Cl2(g); Kp = 1.7 10-2
E) 2NO2(g)--> 2NO(g) + O2(g); Kp = 5.9 10-5
Answer:
D) 2 NOCl(g) ⇄ 2 NO(g) + Cl₂(g); Kp = 1.7 × 10⁻²
Explanation:
In order to compare the degree of decomposition of these reactions, we have to compare the equilibrium constant Kp. Kp is equal to the partial pressure of the products raised to their stoichiometric coefficients divided by the partial pressure of the reactants raised to their stoichiometric coefficients. The higher the Kp, the more products and fewer reactants at equilibrium. Among these reactions, D is the one that has the highest Kp, therefore the one experiencing the largest degree of decomposition.
Given the electronegativities below, which covalent single bond is most polar?
Element: H C N O
Electronegativity: 2.1 2.5 3.0 3.5
A) N-H B) O-C C) O-N D) C-H E) O-H
Answer:
So the correct answer is e) O-H
Explanation:
To determine the most polar bond we calculate the electronegativity difference in each bond and determine the highest value:
a) N-H = 3.0 - 2.1 = 0.9
b) O-C = 3.5 - 2.5 = 1
c) O-N = 3.5 - 3 = 0.5
d) C-H = 2.5 - 2.1 = 0.4
e) O-H = 3.5 - 2.1 = 1.4
So the correct answer is e) O-H
In which of the following reactions does a decrease in the volume of the reaction vessel at constant
temperature favor formation of the products?
A) 2H2(g) + O2(g)--> 2H2O(g)
B) NO2(g) + CO(g)--> NO(g) + CO2(g)
C) H2(g) + I2(g)--> 2HI(g)
D) 2O3(g)--> 3O2(g)
E) MgCO3(s)--> MgO(s) + CO2(g)
Answer:
The correct option is: A) 2H₂(g) + O₂(g) → 2H₂O(g)
Explanation:
According to the Le Chatelier's principle, change in the volume of the reaction system causes equilibrium to shift in the direction that reduces the effect of the volume change.
When the volume decreases then the pressure of the reaction vessel increases, then the equilibrium shifts towards the reaction side that produces less number of moles of gas.
A) 2H₂(g) + O₂(g) → 2H₂O(g)
The number of moles of reactant is 3 and number of moles of product is 2.
Therefore, when volume decreases, the equilibrium shifts towards the product side, thereby favoring the formation of products.
B) NO₂(g) + CO(g) → NO(g) + CO₂(g)
The number of moles of reactant and product both is 2.
Therefore, when the volume decreases, the equilibrium does not shift in any direction.
C) H₂(g) + I₂(g) → 2HI(g)
The number of moles of reactant and product both is 2.
Therefore, when the volume decreases, the equilibrium does not shift in any direction.
D) 2O₃(g) → 3O₂(g)
The number of moles of reactant is 2 and number of moles of product is 3.
Therefore, when volume decreases, the equilibrium shifts towards the reactant side, thereby favoring the formation of reactants.
E) MgCO₃(s) → MgO(s) + CO₂(g)
The number of moles of reactant is 1 and number of moles of product is 2.
Therefore, when volume decreases, the equilibrium shifts towards the reactant side, thereby favoring the formation of reactants.
Fe(II) can be precipitated from a slightly basic (aq) solution by bubbling oxygen through the solution, which converts Fe(II) to insoluble Fe(III):4Fe(OH)+(aq)+ 4OH-(aq)+O2(g)+2H2O(l)=4Fe(OH)3(s)how many grams of O2 are consumed to precipitate all of the iron in 85ml of 0.075 M Fe(II).
Answer:
0,051g of O₂ are consumed
Explanation:
The reaction of precipitation of Fe(II) is:
4Fe(OH)⁺(aq) + 4OH⁻(aq) + O₂(g) + 2H₂O(l) → 4Fe(OH)₃(s)
The moles of Fe(II) you have in 85ml of 0.075 M Fe(II) are:
0,085L×0,075M = 6,4x10⁻³ moles of Fe(II)
For the reaction, you require 4 moles of Fe(II) and 1 mol of O₂(g) to precipitate the iron. Thus, moles of O₂(g) you require are:
6,4x10⁻³ moles of Fe(II)×[tex]\frac{1molO_2}{4molesFe(II)}[/tex] = 1,6x10⁻³ moles of O₂(g)
These moles are:
1,6x10⁻³ moles of O₂(g)×[tex]\frac{32g}{1mol}[/tex] = 0,051g of O₂ are consumed
I hope it helps!
Which of these statements is true?
(a) All spontaneous reactions have a negative enthalpy change
(b) All spontaneous reactions have a positive entropy change
(c) All spontaneous reactions have a positive free-energy change
(d) All spontaneous reactions have a negative free-energy change
(e) All spontaneous reactions have a negative entropy change
Answer:
(d) All spontaneous reactions have a negative free-energy change
Explanation:
All spontaneous reactions releases free energy which can be used later for the work to be done. A reaction with a negative value for ΔG releases free energy and is thus spontaneous
Among the options listed, the correct statement is that all spontaneous reactions result in a negative free-energy change, reflecting the energy released during the process. So the correct option is d.
Explanation:The true statement among the options provided is:
(d) All spontaneous reactions have a negative free-energy change.
This is based on the principles of thermodynamics. The second law of thermodynamics states that the entropy of the universe increases in the course of spontaneous reactions. Nevertheless, a characteristic of spontaneous processes is that they release free energy, leading to a negative change in Gibbs free energy (ΔG). Therefore, not all spontaneous reactions have a negative enthalpy change (ΔH), nor do they always have a positive entropy change (ΔS), but they must result in a decrease in Gibbs free energy (negative free-energy change).
The unit cell in a crystal of diamond belongs to a crystal system different from any we have discussed. The volume of a unit cell of diamond is 0.0454 nm3 and the density of diamond is 3.52 g/cm3. Find the number of carbon atoms in a unit cell of diamond.
Answer:
8.03 atoms of carbon
Given data;
Volume of unit cell diamond = 0.0454 nm³ (4.54×10⁻²³cm³)
Density = 3.52 g/cm³
Number of atoms = ?
Solution;
d = m/v
m = d × v
m = 3.52 g/cm³ × 4.54×10⁻²³cm³
m = 16 ×10⁻²³ g
Now we will determine the moles:
Number of moles of carbon = mass/ molar mass
Number of moles of carbon = 16 ×10⁻²³ g/ 12 g/mol
Number of moles of carbon = 1.3 ×10⁻²³ mol
one mole = 6.022 ×10²³ atoms
1.3 ×10⁻²³ mol × 6.022 ×10²³ atoms / 1mol
8.03 atoms of carbon
There are eight carbon atoms in the unit cell of a diamond, calculated using the provided unit cell volume and the density of diamond. The unit cell volume was first converted from nm³ to cm³, and then the mass of the unit cell was calculated using the formula for density. Finally, the number of atoms was found by dividing this mass by the molar mass of carbon and multiplying by Avogadro's number.
Explanation:The number of carbon atoms in a unit cell of a diamond can be calculated using the provided information of the diamond's crystal system, unit cell volume, and density. When pure, every carbon atom in a diamond forms four single bonds to four other atoms at the corners making the diamond a giant molecule. Consequently, diamond crystals are very hard and have high melting points.
First, convert the unit cell volume from nm³ to cm³. In the case of diamond, the unit cell volume is 0.0454 nm³, which is equivalent to 4.54 × 10-²³ cm³. Then you can use the formula for density (d=mass/volume) to calculate the mass of the unit cell, which is approximately 1.6 × 10-²² g. To find the number of atoms in the unit cell, we divide this mass by the molar mass of carbon, 12.01 g/mol, which gives us the number of moles, and then multiply by Avogadro's number (6.022 x 10²³ atoms/mole) to get the number of atoms. Therefore, there are eight carbon atoms in a unit cell of diamond.
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A 9.96 mL sample of nitric acid required 13.25 mL of 0.085 M strontium hydroxide for titration. Calculate the molarity of the acid solution. (Hint: It's stoichiometry, you need the balanced equation)
The molarity of the nitric acid solution can be calculated using the principles of stoichiometry and titration. By knowing the molarity and volume of strontium hydroxide, we can determine the moles of nitric acid due to a 1:1 stoichiometry in the balanced equation. The molarity of nitric acid is found to be 1.13 M.
Explanation:The subject of the question is related to a concept in chemistry known as titration which is used to determine the concentration of an unknown solution (in this case, nitric acid) using a known solution (strontium hydroxide). Given that the volume of nitric acid is 9.96 mL and the volume and molarity of strontium hydroxide are 13.25 mL and 0.085 M respectively, we can determine the molarity of the nitric acid.
The balanced chemical equation for this acid-base reaction is HNO3(aq) + Sr(OH)2(aq) -> Sr(NO3)2(aq) + 2H2O(l). From this, we can see that one molecule of nitric acid reacts with one molecule of strontium hydroxide. Hence, we can apply the principle of stoichiometry and say that the moles of strontium hydroxide used in the titration are equal to the moles of nitric acid present in the solution.
The moles of strontium hydroxide can be calculated as Molarity x Volume (in L), which gives 0.085 mol/L * 13.25 mL = 0.01126 mol. Since the stoichiometry between strontium hydroxide and nitric acid is 1:1, this is also the moles of nitric acid in our sample. The molarity of nitric acid is then calculated as moles of solute/volume of solution in L, providing us with the molarity. Molarity = 0.01126 mol / 0.00996 L = 1.13 M.
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Which of the following chemical reactions has positive entropy change?
A. N2(g) + 3 H2(g) \longrightarrow ⟶ 2NH3(g)
B. Br2(g) \longrightarrow ⟶ Br2(l) N2O4(g)
C. \longrightarrow ⟶ 2 NO2(g)
D. NaOH(aq) + CO2(g) \longrightarrow ⟶ NaHCO3(aq)
Answer: [tex]N_2O_4(g)\longrightarrow 2NO_2(g)[/tex]
Explanation:
Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.
[tex]\Delta S[/tex] is positive when randomness increases and [tex]\Delta S[/tex] is negative when randomness decreases.
a) [tex]N_2(g)+3H_2(g)\longrightarrow 2NH_3(g)[/tex]
4 moles of gas are converting to moles of gas, hence the entropy decreases.
b) [tex]Br_2(g)\longrightarrow Br_2(l)[/tex]
1 mole of gas is converting to 1 mole of liquid, hence the entropy decreases.
c) [tex]N_2O_4(g)\longrightarrow 2NO_2(g)[/tex]
1 mole of gas is converting to 2 moles of gas, hence the entropy increases.
d) [tex]NaOH(aq)+CO_2(g)\longrightarrow NaHCO_3(aq)[/tex]
1 mole of gas is disappearing , hence the entropy decreases.
Thus [tex]N_2O_4(g)\longrightarrow 2NO_2(g)[/tex] has positive entropy change.