Answer:
25 coolers are need to be produce and sell in order to minimize the cost.
Explanation:
[tex]C = 0.005x^2-0.25x+12[/tex] ..[1]
Differentiating the given expression with respect to dx.
[tex]\frac{dC}{dx}=\frac{d(0.005x^2-0.25x+12)}{dx}[/tex]
[tex]\frac{dC}{dx}=0.01x-0.25+0[/tex]
Putting ,[tex]\frac{dC}{dx}=0[/tex]
[tex]0=0.01x-0.25+0[/tex]
[tex]0.01x=0.25[/tex]
x = 25
Taking second derivative of expression [1]
[tex]\frac{d^2C}{dx^2}=\frac{d(0.01x-0.25)}{dx}=0.01[/tex]
[tex]\frac{d^2C}{dx^2}>0[/tex] (minima)
25 coolers are need to be produce and sell in order to minimize the cost.
What is the volume of the solution produced when enough water is added to 42.0 g of mgcl2 ⋅ 6h2o to yield a solution that has a cl- ion concentration of 0.500m?
Answer:
827 mL
Explanation:
To answer this question we use the definition of Molarity:
Molarity = mol / L
[Cl⁻] = mol Cl⁻ / L
Now we calculate the moles of Cl⁻ present in 42.0 g of MgCl₂⋅6H₂O:
Molar mass of MgCl₂⋅6H₂O = 24.3 + 2*35.45 + 6*18 = 203.2 g/mol
moles of Cl⁻ = 42.0 g MgCl₂⋅6H₂O ÷ 203.2 g/mol * [tex]\frac{2molCl^{-}}{1molMgCl_{2}.6H_{2}O}[/tex] = 0.4134 mol Cl⁻
Finally we use the definition of molarity to calculate the volume:
0.500 M = 0.4134 mol Cl⁻ / xL
xL = 0.827 L = 827 mL
Ne, Ar, and Kr have which properties in common? Group of answer choices
They are gases at STP, unreactive, and are generally monatomic.
They are gases at STP, unreactive, and are generally diatomic.
They are gases at STP, reactive, and are generally monatomic.
They are gases at STP, reactive, and are generally diatomic.
Answer:
Ne, Ar, and Kr are gases at STP, unreactive, and are generally monatomic.
Explanation:
they are unreactive and monoatomic and thats why have a very low boiling point.
The correct answer is: They are gases at STP, unreactive, and are generally monatomic.
Neon (Ne), Argon (Ar), and Krypton (Kr) are all noble gases, which are elements in Group 18 of the periodic table. The properties of noble gases are well-known and include the following:
1. State at STP (Standard Temperature and Pressure): At STP, all noble gases are in the gaseous state. This is because they have relatively low boiling points and exist as gases under normal conditions.
2. Reactivity: Noble gases are known for their lack of reactivity. They have a full valence shell, which means they do not readily form chemical bonds with other elements. This makes them very stable and unreactive under most conditions.
3. Atomicity: Noble gases are generally monatomic, meaning they consist of single atoms rather than molecules made up of two or more atoms. This is due to their stable electron configurations, which do not require sharing or transferring electrons to achieve stability.
Given these properties, the only option that accurately describes Ne, Ar, and Kr is that they are gases at STP, unreactive, and generally monatomic. The other options incorrectly describe either their state at STP, their reactivity, or their atomicity.
450g of chromium (III) sulfate reacts with excess potassium phosphate. How many grams of potassium sulfate will be produced? (ANS: 6.0x10˄2 g K2SO4)
Answer:
599.26 grams of potassium sulfate will be produced.
Explanation:
[tex]Cr_2(SO_4)_3(aq)+2K_3PO_4(aq)\rightarrow 2CrPO_4(s)+3K_2SO_4(aq)[/tex]
Moles of chromium (III) sulfate = [tex]\frac{450 g}{392 g/mol}=1.1480 mol[/tex]
According to reaction, 1 mole of chromium (III) sulfate gives 3 moles of potassium sulfate.
Then 1.1480 moles of chromium (III) sulfate will give:
[tex]\frac{3}{1}\times 1.1480 mol=3.4440 mol[/tex]
Mass of 3.4440 moles of potassium sulfate:
= 3.4440 mol × 174 g/mol = 599.26 g
599.26 grams of potassium sulfate will be produced.
What is meant by "the energy of an electron is quantized"?
a. The quantity of electron energy can be measured.
b. Each electron around an atom has a discrete measure of energy.
c. The quantity of electron energy changes as it moves around the nucleus.
d. All of the above
Answer:
a and B are correct
Explanation:
The energy of an electron associated with one shell around the nucleus is quantized. And is given by the formula
[tex]E= -\frac{13.6 eV}{n^2}[/tex].
where n= shell number 1,2,3...
It is true that energy of an electron cab be measured and Each electron around an atom has a discrete measure of energy associated with it. Moreover, quantity of electron energy remains constant in a shell and changes only when the electron changes its shell.
hence C is incorrect.
Answer: B: Each electron around an atom has a discrete measure of energy.
[tex]MnO_4^- (aq) + H_2C_2O_4 (aq) \rightarrow Mn_2^+ (aq) + CO_2 (g)[/tex]
1. What element is being reduced in this redox reaction?
2. What element is being oxidized in the reaction?
3. What is the reducing agent?
4. What is the oxidizing agent?
5. Balance the reaction in an acidic solution and indicate how many moles of electrons are being transferred.
Answer:
1. C has been oxidized in the reaction.
2. Mn has been reduced in the reaction.
3/4 The reducing agent is the C and the oxidizing agent is the Mn.
The reaction in an acidic solution is:
16H⁺ + 2MnO₄⁻ + 5C₂O₄⁻² → 10CO₂ + 2Mn²⁺ + 8H₂O
10 moles of electrons are been transferred.
Explanation:
MnO₄⁻ (aq) + H₂C₂O₄ (aq) → Mn²⁺ (aq) + CO₂ (g)
In the permanganate, Mn acts with +7 as oxidation number, and in product side, we have Mn2+. It has decrease the oxidation number, so it has been reduced. This is the oxidizing agent.
In the oxalic acid, carbon has +3 as oxidation number, and in CO2, we see that acts with +4 so, it has increase it. This element is the reducing agent and has been oxidated.
8H⁺ + MnO₄⁻ + 5e⁻ → Mn²⁺ + 4H₂O
It is completed on the opposite side where there are oxygen, with as many water as there are oxygen, and on the opposite side complete with protons to balance the H
C₂O₄⁻² → 2CO₂ + 2e⁻
In oxalate, the carbon that acted with +3 gained an electron to oxidize to +4, but since there are 2 carbons, it gained 2 electrons. The oxygen is balanced by adding a 2 in stoichiometry
The halfs reaction have to be multipplied .2 (reduction) and .5 (oxidation) to balance the electrons in the main equation.
(8H⁺ + MnO₄⁻ + 5e⁻ → Mn²⁺ + 4H₂O) . 2
(C₂O₄⁻² → 2CO₂ + 2e⁻ ) . 5
16H⁺ + 2MnO₄⁻ + 10e⁻ + 5C₂O₄⁻² → 10CO₂ + 10e⁻ + 2Mn²⁺ + 8H₂O
16H⁺ + 2MnO₄⁻ + 5C₂O₄⁻² → 10CO₂ + 2Mn²⁺ + 8H₂O
A 275-mL flask contains pure helium at a pressure of 752 torr. A second flask with a volume of 475 mL contains pure argon at a pressure of 722 torr. If the two flasks are connected through a stopcock and the stopcock is opened, what is the partial pressure of each gas and the total pressure?
Answer:
Partial pressure He = 276 torrPartial pressure Ar = 457 torrTotal pressure = 733 torrExplanation:
Assuming temperature remains constant, we can use Boyle's law to solve this problem: P₁V₁=P₂V₂.
Once the two flasks are connected and the stopock opened, the total volume is:
275 + 475 = 750 mLNow we use Boyle's law twice, to calculate the new pressure of each gas:
He ⇒ 752 torr * 275 mL = P₂He * 750 mLP₂He = 276 torr
Ar ⇒ 722 torr * 475 mL = P₂Ar * 750 mLP₂Ar = 457 torr
Finally we calculate the total pressure, adding the partial pressures:
Total pressure = P₂He + P₂Ar = 733 torrA sample of carbon dioxide gas is reduced to 1/3 of its original volume while the pressure is observed to doubleplaced in a container the volume of the container is in the system did the temperature change?
Answer:
The temperature will change and become 2/3 of its original.
Explanation:
Using Ideal gas equation for same mole of gas as
[tex] \frac {{P_1}\times {V_1}}{T_1}=\frac {{P_2}\times {V_2}}{T_2}[/tex]
Given ,
The volume of the sample gets reduced 1/3 of the original. So,
V₂ = 1/3V₁
The pressure of the sample is doubled of the original. So,
P₂ = 2P₁
Using above equation as:
[tex] \frac {{P_1}\times {V_1}}{T_1}=\frac {{P_2}\times {V_2}}{T_2}[/tex]
[tex] \frac {{P_1}\times {V_1}}{T_1}=\frac {{2\times P_1}\times {\frac{1}{3}\times V_1}}{T_2}[/tex]
[tex]T_2=\frac{2}{3}\times T_1[/tex]
The temperature will change and become 2/3 of its original.
In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction.A student heats 61.68 grams of gold to 99.01 °C and then drops it into a cup containing 79.34 grams of water at 22.14 °C. She measures the final temperature to be 23.98 °C.The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.80 J/°C.Assuming that no heat is lost to the surroundings calculate the specific heat of gold.
Answer:
Specific heat of gold is 0,133J/g°C
Explanation:
In this problem, the heat of the gold is transferred to water and the calorimeter, that means:
[tex]q_{Lost By Metal} = q_{GainedWater} + q_{Gained Calorimeter}[/tex]
The Q lost by metal is:
Q = C×m×ΔT, Where m is mass (61,68g), ΔT is (99,01°C-23,98°C = 75,03°C) and C is sepecific heat of gold
The Q gained by water is:
Q = C×m×ΔT, Where m is mass (79,34g), ΔT is (23,98°C-22,14°C = 1,84°C) and C is sepecific heat of water (4,184J/g°C)
The Q gained by calorimeter is:
Q =Cc×ΔT Where Cc is calorimeter constant (1,80J/°C), and ΔT is (23,98°C-22,14°C = 1,84°C)
Replacing:
C×61,68g×75,03°C = 4,184J/g°C×79,34g×1,84°C + 1,80J/°C×1,84°C
4628g°C×C = 610,8J + 3,3J
4628g°C×C = 614,1J
C = 0,133J/g°C
I hope it helps
The specific heat of gold can be calculated using the equation representing the transfer of heat in the experiment. The sum of the heat absorbed by the water and the calorimeter (each calculated using respective mass, specific heat, and temperature change) equals the heat lost by the gold.
Explanation:The specific heat of a substance is typically calculated using the formula q = mcΔT, where q is the heat absorbed, m is the mass, c is the specific heat, and ΔT is the change in temperature. In this experiment, heat is transferred from the gold to the water and the calorimeter, so we need to set up an equation with the sum of the heat absorbed by the water and the calorimeter equal to the heat lost by the gold.
For the water, we use the specific heat value of water as 4.18 J/g°C, and for the calorimeter, we use the given calorimeter constant. Setting up the equation and solving for the specific heat of gold gives:
(61.68g)(c)[99.01°C-23.98°C] = (79.34g)(4.18 J/g°C)[23.98°C-22.14°C] + (1.80 J/°C)(23.98°C-22.14°C)
Solving the above equation will yield the specific heat of gold.
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What is the difference between a strong and weak acid?
Answer:
The strong acids are fully ionized in aqueous solution, and they contains higher concentration of hydrogen ions. Strong acids are lower pH in nature. Some examples of strong acids are:
1) Hydrochloric acid.
2) Nitric acid.
3) Sulfuric acid.
The weak acids are not fully ionized, means they are partially ionized in aqueous solution, and they contains lower concentration of hydrogen ions. Weak acids are higher pH in nature than strong acid. Some examples of weak acids are:
1) Ethanoic acid.
2) Acetic acid.
3) Nitrous acid.
Two flasks of equal volume and at the same temperature contain different gases. One flask contains 5.0 g of O2, and the other flask contains 5.0 g of H2. Is each of the following statements true or false? Explain.
a) True. Because the gases have the same volumes, they must have the same number of molecules.
b) False. Because the molar mass of O2 is greater than the molar mass of H2, 5.0g of O2 will contain fewer molecules than 5.0 g of H2.
c)False. Depending on the pressure each flask may contain different numbers of molecules.
Statement a is true because of Avogadro's Law. Statement b is also true since molar mass of O2 is greater than H2, so 5.0g of O2 contains fewer molecules than H2. Statement c is false as the number of molecules in given volume and temperature is constant.
Explanation:The subject of this question is chemistry, specifically the concept of Avogadro's law. Avogadro's law states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
Statement a is TRUE. Given equal volumes and temperatures, the flasks do contain the same number of molecules. This principle is referred to as Avogadro's Law.
Statement b is TRUE. The molar mass of O2 is indeed greater than H2, meaning that 5.0 g of O2 has fewer molecules than 5.0 g of H2, contrary to what statement b suggests.
Statement c is FALSE. Equal volume flasks at the same temperature will have the same number of molecules, regardless of pressure. Which specific gas is involved does not change this fact.
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The correct options are as follows:
a) False. Because the molar mass of O2 is greater than the molar mass of H2, 5.0 g of O2 will contain fewer molecules than 5.0 g of H2.
b) True. Because the molar mass of O2 is greater than the molar mass of H2, 5.0 g of O2 will contain fewer molecules than 5.0 g of H2.
c) False. Regardless of the pressure, if the volumes and temperatures are the same, the number of molecules will be the same due to Avogadro's Law.
Let's analyze each statement:
a) This statement is false. The volume of a gas is directly proportional to the number of moles of gas at a constant temperature and pressure (Avogadro's Law). Since the molar mass of O2 (approximately 32 g/mol) is much greater than that of H2 (approximately 2 g/mol), 5.0 g of O2 will represent fewer moles than 5.0 g of H2. Consequently, the flask containing O2 will have fewer molecules than the flask containing H2, despite the volumes being equal.
b) This statement is true. As explained above, because O2 has a higher molar mass than H2, 5.0 g of O2 will contain fewer moles and hence fewer molecules than 5.0 g of H2.
c) This statement is false. According to Avogadro's Law, equal volumes of gases at the same temperature and pressure contain the same number of molecules. Therefore, the pressure does not affect the number of molecules if the volume and temperature are constant. The number of molecules in each flask will be the same because both flasks are at the same temperature and have the same volume. The pressure within each flask will adjust according to the number of moles of gas present (as per the ideal gas law, PV = nRT), but this does not change the number of molecules.
To calculate the number of moles for each gas:
For O2:
Number of moles of O2 = mass of O2 / molar mass of O2
Number of moles of O2 = 5.0 g / 32 g/mol ≈ 0.156 mol
For H2:
Number of moles of H2 = mass of H2 / molar mass of H2
Number of moles of H2 = 5.0 g / 2 g/mol = 2.5 mol
Clearly, the number of moles of H2 is greater than the number of moles of O2 for the same mass, which confirms that the number of molecules in the H2 flask is greater than in the O2 flask.
Whats the formula for selenium pentaoxide, iodine trichloride, zinc (1) nitride, chromium (III) bicarbonate, and there molar mass
Answer one of them plz and thx
Answer:
1) Se2O5
2) I2O6
3)Zn3n2
4) Cr(HCO3)3
Explanation:
selenium pentaoxide (= also called diselenium pentoxide)
= Se2O5
⇒ Se = 78.97 g/mol
⇒ O = 16 g/mol
⇒ 2*78.97 + 5*16 = 237.94 g/mol
iodine trichloride
= I2O6
⇒ I = 126.9 g/mol
⇒ Cl = 35.45 g/mol
⇒ 2* 126.9 + 6 * 35.45 = 466.5 g/mol
zinc (1) nitride does not exist (it's Zinc(ii)nitride
The oxidation number for zinc is always 2
Zn3n2
⇒ Zn = 65.38 g/mol
⇒ N = 14 g/mol
⇒3*65.38 + 2* 14 = 224.14 g/mol
chromium (III) bicarbonate
Cr(HCO3)3
⇒ Cr = 52 g/mol
⇒ H = 1.01 g/mol
⇒ C = 12 g/mol
⇒ O = 16 g/mol
52 + 3*1.01 + 3*12 + 6*16 = 235.03 g/mol
A student listed the characteristics of chemical and nuclear reactions.
Chemical and Nuclear Reactions
A -->Total mass remains unchanged
B --> Small change in mass takes place
Which of these statements best explains the identity of Reaction A?
A. It is a nuclear reaction because the total mass remains the same when there is a change in the number of protons and neutrons.
B. It is a chemical reaction because the total mass remains the same when the nuclei of the atoms reacting split.
C. It is a nuclear reaction because the total mass remains the same when there is a change in the overall energy of the system.
D. It is a chemical reaction because the total mass remains the same when new substances are formed.
Answer:
D. It is a chemical reaction because the total mass remains the same when new substances are formed.
Explanation:
A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.
For example:
6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂
it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.
While in case of nuclear reaction small change in mass take place.
Answer: D
Explanation: Just took the test
A reaction of 0.028 g of magnesium with excess hydrochloric acid generated 31.0 mL of hydrogen gas. The gas was collected by water displacement in a 22 °C water bath. The barometric pressure in the lab that day was 746 mm Hg.Use Dalton's law to calculate the partial pressure of hydrogen gas in the gas-collecting tube.
Answer : The partial pressure of [tex]H_2[/tex] is, 726.2 mmHg
Solution :
According to the Dalton's law, the total pressure of the gas is equal to the sum of the partial pressure of the mixture of gasses.
[tex]P_T=p_{H_2}+p_{H_2O}[/tex]
where,
[tex]P_T[/tex] = total partial pressure = barometric pressure = 746 mmHg
[tex]P_{H_2}[/tex] = partial pressure of hydrogen gas = ?
[tex]P_{H_2O}[/tex] = partial pressure of water vapor = 19.8 mmHg (assume)
Now put all the given values is expression, we get the partial pressure of the hydrogen gas.
[tex]746mmHg=p_{H_2}+19.8mmHg[/tex]
[tex]p_{H_2}=726.2mmHg[/tex]
Therefore, the partial pressure of [tex]H_2[/tex] is, 726.2 mmHg
A balloon containing methane gas has a volume of 2.64 L at 31.0 C. What volume will the balloon occupy at 62.0 C?
Answer:
The balloon will occupy the volume of 2.91 L at 62.0 °C .
Explanation:
Using Charle's law
[tex]\frac {V_1}{T_1}=\frac {V_2}{T_2}[/tex]
Given ,
V₁ = 2.64 L
V₂ = ?
T₁ = 31.0 °C
T₂ = 62.0 °C
The conversion of T( °C) to T(K) is shown below:
T(K) = T( °C) + 273.15
So,
T₁ = (31.0 + 273.15) K = 304.15 K
T₂ = (62 + 273.15) K = 335.15 K
Using above equation as:
[tex]\frac{2.64}{304.15}=\frac{V_2}{335.15}[/tex]
[tex]V_2=\frac{2.64\cdot \:335.15}{304.15}[/tex]
New volume = 2.91 L
The balloon will occupy the volume of 2.91 L at 62.0 °C .
What are hydrogen bonds? What type of molecules do hydrogen bonds occur in?
What c5h12 isomer will give only a single monochlorination product?
Answer:
Hence neopentane will give only single monochlorination product.
Explanation:
see below
The statement of C5H12 isomer will give only a single monochlorination product is "neopentane."
What is monochlorination?Monochlorination is the process of replacing one of the hydrogen atoms in an alkane with a chlorine atom. This is accomplished by chlorinating the alkane in the presence of UV radiation. The chlorine molecule splits into chlorine free radicals under these conditions. A monochlorination product is a chemical with two chlorine atoms in it.
Only one monochloroderivative is produced by the C5H12 isomer, implying that all hydrogen is equal. It's got to be neopentane. As a result, neopentane is the sole chemical that produces only one monochlorination product when chlorinated in the presence of sunlight.
Hence the correct option is neopentane.
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Which of the compounds below is not an example of a molecular solid?
A. CO2(s)
B. C25H52(s)
C. SiO2(s)
D. I2(s)
E. H2O(s)
SiO₂(s) is not an example of a molecular solid
A molecular solid is a of solid in which its molecules are held together by weak intermolecular forces such as van der Waals forces.
Molecular solids are soft, often volatile, have low density, have low melting temperatures, and are electrical insulators.
Example of molecular solid include CO₂(s) (dry ice), iodine (I₂(s)), C₂₅H₅₂(s) (paraffin wax), H₂O(s)
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In which of the following processes is it necessary to break covalent bonds as opposed to simply overcoming intermolecular forces?
A. Melting mothballs
B. Dissolving hydrogen bromide gas in water to form hydrobromic acid
C. Vaporizing ethyl alcohol
D. Changing ozone to oxygen gas
Answer:
D. Changing ozone to oxygen gas
Explanation:
As a rule of thumb, it is always noting that making putting a substance through physical changes like melting or boiling, evaporating involves breaking intermolecular bonds. On the other hand, making a substance undergo chemical changes involves breaking intramolecular bonds like ionic bonds and covalent bonds.
Oxygen being changed from ozone to oxygen is a chemical change and therefore requires breaking of the oxygen-oxygen double bonds
Final answer:
Breaking covalent bonds is necessary in changing ozone to oxygen gas, while the other processes listed involve overcoming intermolecular forces.
Explanation:
In the processes described, breaking covalent bonds is necessary when changing ozone (O3) to oxygen gas (O2). Melting mothballs, dissolving hydrogen bromide gas into water to form hydrobromic acid, and vaporizing ethyl alcohol involve overcoming intermolecular forces rather than breaking covalent bonds. The transition from ozone to oxygen involves an endothermic reaction breaking the O-O covalent bonds within the ozone molecule to form diatomic oxygen molecules.
The Ksp of Al(OH)3 is 1.0 x 10-33. What is the solubility of Al(OH)3 in a solution that has pH = 12? Give your answer using scientific notation and to 2 significant figures (i.e., one decimal place).
Answer : The solubility of [tex]Al(OH)_3[/tex] is [tex]1.0\times 10^{-27}M[/tex]
Explanation :
First we have to calculate the pOH.
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-12\\\\pOH=2[/tex]
Now we have to calculate the concentration of [tex]OH^-[/tex].
[tex]pOH=-\log [OH^-][/tex]
[tex]2=-\log [OH^-][/tex]
[tex][OH^-]=0.01[/tex]
The solubility equilibrium reaction will be:
[tex]Al(OH)_3\rightleftharpoons Al^{3+}+3OH^{-}[/tex]
The expression for solubility constant for this reaction will be,
[tex]K_{sp}=[Al^{3+}][OH^{-}]^3[/tex]
Now put all the given values in this expression, we get:
[tex]1.0\times 10^{-33}=[Al^{3+}]\times (0.01)^3[/tex]
[tex][Al^{3+}]=1.0\times 10^{-27}M[/tex]
As, the solubility of [tex]Al(OH)_3[/tex] = [tex][Al^{3+}][/tex] = [tex]1.0\times 10^{-27}M[/tex]
Thus, the solubility of [tex]Al(OH)_3[/tex] is [tex]1.0\times 10^{-27}M[/tex]
The Earth’s atmosphere contains about 0.04% (or 400 parts per million) carbon dioxide. Although most of the carbon dioxide is in the form 12CO2, which is not radioactive, a specific fraction of the total is made up of radioactive 14CO2.
A) True
B) False
Answer:
True
Explanation:
Yes the given statement is true
Most of the carbon dioxide preset in the atmosphere is C12 isotope and a very small fraction of The atmosphere is made up by C14 isotope which is radioactive in nature
C14 makes about 1 to 1.5 atoms per [tex]10^{12}[/tex] atoms of carbon in the atmosphere.
1. How many negative ones (-1) would you need to balance out one positive 2 (+2)?
Question options:
Two negative ones balance out two positive twos
One negative one balances out one positive two
Two negative ones balance out one positive two
One negative one balances out two positive twos
2. Potassium forms ions with a charge of +1 (Ka+). Iodine forms ions with a charge of -1. Selenium forms ions with a charge of -2 (Se2-).
Imagine that Potassium ions and Selenide ions combine to form Potassium Selenide. What numbers would be in the place of X and Y in:
KXSeY
(Use the number 1 even if it isn't strictly necessary)
X=______ Y =______
3. You are balancing an ionic compound. Let's call it: AB.
Ion A has a charge of +2 and Ion B has a charge of -3.
Therefore, you determine that the ionic compound (AB) will have a ratio of 3 As for every 2 Bs.
How would you modify AB in order to show that they have this 3-to-2 ratio?
Question options:
3A2B
A3B2
A3B2
4. Calcium forms ions with a charge of +2. Iodine forms ions with a charge of -1.
Which of the following would represent an ionic compound composed of Calcium and Iodide ions?
Question options:
CaI2
CaI
Ca2I
Ca2I
2CaI
CaI2
1) The number of negative ones (-1) would you need to balance out one positive 2 (+2) is;
Option C; Two negative ones balance out one positive two
2) The numbers that would be in the place of X and Y in [tex]K_{X}Se_{Y}[/tex] is;
X = 2 and Y = 1
3) AB will be modified in order to show that they have this 3-to-2 ratio as;
Option B; A₃B₂.
4) The formula that will represent an ionic compound composed of Calcium and Iodide ions is; Option A; CaI₂
1) To balance out the ions, it means addition of them should be equal to zero. Thus, to balance out one positive two (+2) with negative 1 (-1), the expression is;
+2 + x(-1) = 0
2 - x = 0
x = 2
Thus, we need 2 negative ones to balance out one positive two.
2) We are told that potassium(K) forms ions with a charge of +1 and selenium (Se) forms ions with a charge of -2.
When two ions combine, the product element will have its' subscript as the absolute value of the ion of its' sharing ion. Thus;
We will have; K₂Se₁
Comparing with [tex]K_{X}Se_{Y}[/tex], then; X = 2 and Y = 1
3) We are told that;
Ion A has a charge of +2 and Ion B has a charge of -3.
From the concept in answer 2 above, it means that the answer will be;
A₃B₂.
4) We are told that;
Calcium forms ions with a charge of +2. Iodine forms ions with a charge of -1. An ionic compound formed by both ions using the concept earlier used would give us; CaI₂
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Assuming that an acetic acid solution is 12% by mass and that the density of the solution is 1.00 g/mL, what volume of 1 M NaOH is needed to fully neutralize a 10 mL aliquot of the acetic acid solution
Explanation:
Let us assume that total mass of the solution is 100 g. And, as it is given that acetic acid solution is 12% by mass which means that mass of acetic acid is 12 g and 88 g is the water.
Now, calculate the number of moles of acetic acid as its molar mass is 60 g/mol.
No. of moles = [tex]\frac{mass}{\text{molar mass}}[/tex]
= [tex]\frac{12 g}{60 g/mol}[/tex]
= 0.2 mol
Molarity of acetic acid is calculated as follows.
Density = [tex]\frac{mass}{volume}[/tex]
1 g/ml = [tex]\frac{100 g}{volume}[/tex]
volume = 100 ml
Hence, molarity = [tex]\frac{\text{no. of moles}}{volume}[/tex]
= [tex]\frac{0.2 mol}{0.1 L}[/tex]
= 2 mol/l
As reaction equation for the given reaction is as follows.
[tex]NaOH + CH_{3}COOH \rightarrow CH_{3}COONa + H_{2}O[/tex]
So, moles of NaOH = moles of acetic acid
Let us suppose that moles of NaOH are "x".
[tex]x \times 1 M = 10 mL \times 2 M[/tex] (as 1 L = 1000 ml)
x = 20 L
Thus, we can conclude that volume of NaOH required is 20 ml.
When a 3.23 g sample of solid sodium hydroxide was dissolved in a calorimeter in 100.0 g of water, the temperature rose from 23.9 °C to 32.0 °C. Calculate ΔH (in kJ/mol NaOH) for the following solution process: NaOH(s) →Na+(aq)+ OH−(aq)
Answer:
-41,9kJ/mol NaOH
Explanation:
For the solution process:
NaOH(s) →Na⁺(aq) + OH⁻(aq)
The released heat is:
Q = -C×m×ΔT
Where Q is the released heat, C is specific heat of the solution (4,18J/g°C), m is the mass of water (100,0g) and ΔT is (32,0°C-23,9°C)
Replacing:
Q = -3385,8J
This heat is released per 3,23g of NaOH. Now, the heat released (ΔH) per mole of NaOH is:
[tex]\frac{-3385,8J}{3,23gNaOH} *\frac{40g}{1mol}[/tex]= -41929J/molNaOH ≡
-41,9kJ/mol NaOH
I hope it helps!
Which element has the same oxidation number in all of its compounds?
Answer:
Sodium, potassium, calcium , magnesium etc
Explanation:
To determine the species which is being oxidized or reduced in a reaction, we make use of oxidation number. While oxidation involves electron loss, reduction involves electron gain. The specie which gain electrons is being reduced and thus experience a decrease in oxidation number and thus said to be the oxidizing agent. The species which lose electrons experience and increase in oxidation number and thus is the reducing agent.
There are some elements however which never get oxidized or reduced in the course of a chemical reaction. What we mean by this is that they neither get oxidized nor reduced but maintain the same original oxidation number.
Examples of these kind of elements include the groups 1 and 2 metals.
When solid KClO3 is heated, it decomposes to give solid KCl and O2 gas. A volume of 262 mL of gas is collected over water at a total pressure 730 mmHg of and 24 ∘C. The vapor pressure of water at 24 ∘C is 22 mmHg:
2KClO3(s)→2KCl(s)+3O2(g)
Part A What was the partial pressure of the O2 gas?
Part B How many moles of O2 gas were in the gas sample?
Answer:
Part A: 708 mmHg
Part B: 0.01 mol O2
Explanation:
Total pressure in a gas mixture = Sum of each partial pressure in the mixture so:
Total pressure = 730mmHg
The mixture has 2 compounds, the O2 and the vapor of water.
730mmHg - 22mmHg = 708 mmHg. Now that we have Pp O2, let's apply the Ideal Gas Law to find the mols
P.V = n . R . T
First of all, covert the mmHg in atm
760 mmHg ____ 1 atm
708 mmHg _____ 708/760 = 0.93 atm
and convert 262mL in L
262/1000 = 0.262L
0.93 atm . 0.262L = n . 0.082 . 297K
(0.93 . 0.262)/ (0.082. 297) = n
0.01 mol = n
The partial pressure of the O2 gas in the reaction of KClO3 decomposing is 708 mmHg, and the number of moles of O2 gas is approximately 0.011 moles.
Explanation:The reaction of potassium chlorate (KClO3) decomposing into solid potassium chloride (KCl) and oxygen (O2) gas when heated is related to the concepts of partial pressure and moles in chemistry.
Part A: The partial pressure of a gas is the pressure contributed by that individual gas in a mixture of gases. If the total pressure is 730 mmHg, and the vapor pressure of water at 24°C is 22 mmHg, the partial pressure of the O2 (oxygen gas) would be the total pressure minus the vapor pressure of water. So, the partial pressure of the O2 gas is 730 mmHg - 22 mmHg = 708 mmHg.
Part B: To find the moles of the O2 gas, the ideal gas law could be used which links pressure, volume, temperature and number of moles in a gas. The law states that (Pressure x Volume) = (number of moles x Ideal Gas Constant x Temperature in Kelvin). We know the volume, partial pressure and absolute temperature, but an appropriate conversion of units is required. Therefore, adjusting to standard SI units, we have the volume 262 mL converted to 0.262 L, the partial pressure 708 mmHg converted to 0.93 atmospheres (1 atmosphere = 760 mmHg), and the temperature 24°C converted to 297 K (Kelvin = Celsius + 273.15). Short calculation later we get around 0.011 moles of O2 gas.
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For the reaction, calculate how many moles of the product form when 0.012 mol of O2 completely reacts. Assume that there is more than enough of the other reactant. 4Al(s)+3O2(g)→2Al2O3(s) Express your answer using two significant figures.
Answer:
0.008
Explanation:
From the balanced equation, 3 moles of oxygen gas produced 2 moles of the product. Then, 0.012 moles of oxygen gas will produces 0.012 x 2/3 = 0.008
When 0.012 mol of O2 completely reacts with excess aluminum according to the balanced chemical equation, 0.008 mol of Al2O3 is produced, rounded to two significant figures.
Explanation:To calculate the number of moles of Al2O3 produced from the complete reaction of 0.012 mol of O2, we use stoichiometry based on the balanced chemical equation:
4Al(s) + 3O2(g) → 2Al2O3(s).
From the equation, 3 moles of oxygen gas (O2) produce 2 moles of aluminum oxide (Al2O3). To find the moles of Al2O3 produced, use the mole ratio:
(mol Al2O3) = (mol O2) × (2 mol Al2O3 / 3 mol O2)
Substituting the given value:
(mol Al2O3) = (0.012 mol O2) × (2 mol Al2O3 / 3 mol O2) = 0.008 mol Al2O3
So, when 0.012 mol of O2 completely reacts, 0.008 mol of Al2O3 is produced, assuming excess aluminum is present. This answer is rounded to two significant figures.
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What is the difference between a positive and negative ion?
Final answer:
A positive ion, or cation, has more protons than electrons, while a negative ion, or anion, has more electrons than protons, resulting in their net electrical charges.
Explanation:
The difference between a positive and negative ion lies in the balance between protons and electrons within an atom or molecule. When an atom has more protons than electrons, it becomes a positive ion or, as it's scientifically named, a cation. Conversely, an atom becomes a negative ion or anion if it gains extra electrons, surpassing the number of protons. This difference in the number of electrons leads to a net electrical charge, which determines whether the ion is positive or negative.
DID YOU KNOW? The names for these ions are pronounced "CAT-eye-ons" (cations) and "ANN-eye-ons" (anions), reflecting their respective charges.
A cell was prepared by dipping a Cu wire and a saturated calomel electrode into 0.10 M CuSO4 solution. The Cu wire was attached to the positive terminal of a potentiometer and the calomel electrode was attached to the negative terminal.(a) Write a half-reaction for the Cu electrode. (Use the lowest possible coefficients. Omit states-of-matter.)
(c) Calculate the cell voltage.
Answer:
a) cu2+ + 1Hg (l) 1Cl- equilibrium cu (s) + Hg2Cl2 (s)
b) 0.068 V.
Explanation:
A) Cu2+ + 2e- euilibrium cu (s)
Hg2Cl2 + 2e- equilibrium 2Hg (l) + 1cl-
Cell Reaction: cu2+ + 1Hg (l) 1Cl- equilibrium cu (s) + Hg2Cl2 (s)
B) To calculate the cell voltage
E = E_o Cu2+/Cu - (0.05916 V / 2) log 1/Cu2+
putting values we get
= 0.339V + (90.05916V/2)log(0.100) = 0.309V
E_cell = E Cu2+/Cu - E SCE = 0.309 V - 0.241 V = 0.068V.
The half-reaction for the copper electrode in a copper sulfate solution is Cu(s) -> Cu2+(aq) + 2e-. However, you cannot calculate the cell voltage without additional information about the Calomel electrode's standard reduction potential.
Explanation:The subject of this question is electrochemistry, which involves redox reactions and measurements of electrode potential.
(a) The half-reaction for the Cu electrode in your scenario, when the Cu wire is dipped into the CuSO4 solution, can be represented as follows: Cu (s) -> Cu2+ (aq) + 2e-. This reaction shows that copper metal (Copper in zero oxidation state) is being oxidized to Copper(II)(in +2 oxidation state) ions by losing 2 electrons.
For the cell voltage, we do not have sufficient information to calculate. To perform this calculation, we would also need the standard reduction potential for the Calomel electrode, or some other point of comparison.
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Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25°C. (The equation is balanced.) Pb(s) + Br2(l) → Pb2+(aq) + 2Br(aq) Pb2+(aq) + 2 e → Pb(s) E° = -0.13 V Br2(l) + 2 e → 2 Br(aq) E° = +1.07 V
Answer:
1.20 V
Explanation:
[tex]Pb(s) + Br_2(l)\rightarrow Pb^{2+}(aq) + 2Br^-(aq)[/tex]
Here Pb undergoes oxidation by loss of electrons, thus act as anode. Bromine undergoes reduction by gain of electrons and thus act as cathode.
[tex]E^0=E^0_{cathode}- E^0_{anode}[/tex]
Where both [tex]E^0[/tex] are standard reduction potentials.
Given,
[tex]Pb^{2+}(aq) + 2 e^-\rightarrow Pb(s)[/tex]
[tex]E^0_{[Pb^{2+}/Pb]}= -0.13\ V[/tex]
[tex]Br_2(l) + 2 e^-\rightarrow 2 Br(aq)[/tex]
[tex]E^0_{[Br_2/Br^{-}]}=+1.07\ V[/tex]
[tex]E^0=E^0_{[Br_2/Br^{-}]}- E^0_{[Pb^{2+}/Pb]}[/tex]
[tex]E^0=+1.07- (-0.13)\ V=1.20\ V[/tex]
The cell potential for the given reaction is calculated by subtracting the anode's potential from the cathode's potential since the reaction at the anode is an oxidation and the cathode involves a reduction. The standard cell potential for this reaction is 1.20 V, and this positive value indicates the reaction is spontaneous under standard conditions.
Explanation:The standard cell potential is calculated by adding the standard reduction potential of the cathode to the standard reduction potential of the anode. According to the reaction, Pb(s) is being oxidized to Pb2+(aq), thus acting as the anode: E° = -0.13 V. Meanwhile, Br2(l) is being reduced to 2Br-(aq), acting as the cathode: E° = +1.07 V. When calculating the overall cell potential, we subtract the anode's potential from the cathode's potential, because the reaction at the anode is oxidation (loss of electrons), while the cathode involves a reduction (gain of electrons).
Therefore, the standard cell potential, E°cell, is calculated as E°cathode - E°anode = 1.07 V - (-0.13 V) = 1.20 V. This value is positive, indicating that the reaction is spontaneous under standard conditions as per the cells' relative oxidizing strength.
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What strategy helps to ensure that your home-canned food does not contain the botulinum toxin?
a. Follow proper canning techniques.
b. Freeze the canned food.
c. Test the soil in which the food was grown.
d. Consume the canned food within 12 months.
e. Add an antioxidant before canning.
Answer:
a. Follow proper canning techniques.
Explanation:
Although home canning is a great way to preserve garden goods it can be very risky or even deadly if not done correctly and safely.
Beware! Your canned vegetables and fruits could cause botulism if home canning is not done the correct way!
Botulism is a rare but potentially deadly disease caused by a poison most commonly produced by a germ called Clostridium Botulinum. The germ can be found in soil and can grow, survive and produce a toxin in certain conditions, such as when food is improperly canned. The toxin can damage your nerves, paralyze you, and even cause death.
You cannot smell, see or taste botulinum toxin but putting even a small amount of food containing botulinum into your organism can be fatal.
Botulism is a medical emergency. If you or someone you know has symptoms of foodborne botulism, see your doctor or go to the emergency room immediately.
Some of the symptoms that may occur are: drooping eyelids, double and/or blurred vision, thick-feeling tongue, muscle weakness, dry mouth, difficulty swallowing, slurred speech etc.
Many cases of foodborne botulism have occurred after people ate home-canned, preserved, or fermented foods that were contaminated with this toxin. The food was contaminated because it wasn’t canned or processed correctly.
You can take these steps to protect yourself, your family, and others when it comes to home-canned foods:
1. Use proper canning techniques by carefully following instructions for safe home canning in the USDA Complete Guide to Home Canning. Do not follow recipes and cookbooks that do not follow the steps in the USDA guide, even if you got these items from a trusted friend or family member.
2. Use the right equipment for the kind of foods that you are canning. Pressure canning is the only recommended method for canning low-acid foods. Foods with low acid content are the most common sources of home-canning related botulism cases. Low-acids foods include almost every vegetable, some fruits, milk, all meats, fish, and seafood. Do not use boiling water canners for low-acid foods because they will not protect against botulism.
3. Do not hesitate! If there is any doubt if safe canning guidelines have been followed, do not eat the food. Home-canned and store-bought food might be contaminated with toxin or other harmful germs if the container is leaking, bulging, or swollen; the container looks damaged, cracked, or abnormal; the container spurts liquid or foam when opened; the food is discolored, moldy, or smells bad.
If the container or the food inside has any signs of contamination, throw it out! If any of the food spills, wipe up the spill using a solution of 1/4 cup bleach for each 2 cups of water.
Never taste food to determine if it is safe! Do not taste or eat food that is discolored, moldy, or smells bad. Do not taste or eat food from cans that are leaking, have bulges or are swollen, or look damaged, cracked, or abnormal. Do not taste or eat food from a can that spurted liquid or foam when it was opened.
Final answer:
The best way to avoid botulinum toxin in home-canned foods is to follow proper canning techniques, specifically using a pressure canner to reach the necessary temperature to kill C. botulinum endospores, and boiling the food for 10 minutes before eating. The correct answer is a. Follow proper canning techniques.
Explanation:
The strategy that helps to ensure that your home-canned food does not contain the botulinum toxin is a. Follow proper canning techniques. This involves using a pressure canner to achieve the necessary temperature of 116 °C (240 °F) to kill C. botulinum endospores, as they can survive temperatures above the boiling point of water.
Furthermore, the Centers for Disease Control and Prevention (CDC) recommend boiling home-canned foods for about 10 minutes before consumption to denature any botulinum toxin that may be present.