Question 1

A copper ore consisting of 12.5% copper(II) sulfide, when heated and reacted with oxygen gas, produces copper(II) oxide and sulfur dioxide. If the reaction has a 90.0% yield, how many grams of copper(II) oxide are produced when 1.00 kg of the copper ore is processed?

Accepted Answer

First, calculate the mass of copper(II) sulfide in 1.00 kg of the ore: $1.00 \, \text{kg} \times 0.125 = 125 \, \text{g}$. The reaction is: $\text{CuS} + \text{O}_2 \rightarrow \text{CuO} + \text{SO}_2$. Molar masses: $\text{CuS} = 95.61 \, \text{g/mol}$, $\text{CuO} = 79.55 \, \text{g/mol}$. Moles of $\text{CuS}$ in 125 g: $125 \, \text{g} / 95.61 \, \text{g/mol} = 1.307 \, \text{mol}$. Moles of $\text{CuO}$ produced (same as $\text{CuS}$ due to 1:1 ratio): $1.307 \, \text{mol}$. Mass of $\text{CuO}$ produced: $1.307 \, \text{mol} \times 79.55 \, \text{g/mol} = 103.96 \, \text{g}$. Considering 90% yield: $103.96 \, \text{g} \times 0.90 = 93.7 \, \text{g}$.

Question 2

A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon?

Accepted Answer

The answer of A hydrocarbon molecule contains carbon and hydrogen...

Question 3

A careless student who was instructed to combine 4.00 g of sodium sulfate with a solution containing 10.0 g of H₂SO₄ (98.08 g/mol) instead combined 4.00 g of sodium sulfide (78.05 g/mol) with the acid. The acid reacted with the sodium sulfide, according to the following reaction, to produce the foul-smelling and highly toxic hydrogen sulfide gas. How many moles of hydrogen sulfide gas were produced? Na₂S(s) + H₂SO₄(aq) $\rightarrow$Na₂SO₄(aq) + H₂S(g)

Accepted Answer

The answer of A careless student who was instructed to...

Question 4

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

Accepted Answer

The combustion analysis relies on the assumption that the compound completely burns to form carbon dioxide and water. This means that all of the carbon in the sample will be present in the carbon dioxide produced, and all of the hydrogen in the sample will be present in the water produced. Therefore, options C and D are also correct, but not as fundamental as option A. Option B is not necessary because the combustion is typically carried out in excess oxygen, so all of the oxygen in the products will come from the added oxygen gas. Option E is not correct because the mass of oxygen in the sample cannot be calculated solely from the masses of carbon dioxide and water produced.

Question 5

U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH)₂. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide?

Accepted Answer

The balanced chemical equation for the reaction is:
Ca(OH)2 → CaO + H2O
The molar mass of Ca(OH)2 is 74 g/mol.
1 mole of Ca(OH)2 produces 1 mole of CaO.
The molar mass of CaO is 56 g/mol.
From the given information, we know that 1 mole of Ca(OH)2 produces 45 grams of CaO.
Therefore, the mass of 1 mole of CaO produced is (45/1)*56 = 2520 g/mol.
The theoretical yield of 1 mole of CaO is 56 g/mol.
The percent yield is (actual yield/theoretical yield)*100.
So, the percent yield is (2520/56)*100 = 80%. 
Therefore, the best choice is B.

Question 6

A reaction vessel contains equal masses of iron and oxygen. How much FeO could theoretically be produced?

Accepted Answer

The balanced equation for the reaction between iron and oxygen to produce FeO is 4Fe + 3O2 --> 2Fe2O3. This means that, for every 4 moles of Fe, we need 3 moles of O2. Since the reaction vessel contains equal masses of Fe and O2, we know that there will be less O2 than we need for a complete reaction. Therefore, we will not be able to produce an amount of FeO equal to the sum of the masses of Fe and O2.

Question 7

Allicin, a potent antibacterial compound, is formed by the enzyme alliinase when garlic is chopped or damaged. Allicin contains carbon, hydrogen, oxygen, and sulfur atoms. In combustion analysis, a 10.00 mg sample of allicin produced 16.27 mg of CO₂, 5.55 mg of water, and 7.90 mg of SO₂. What is the empirical formula of allicin?

Accepted Answer

The answer of Allicin, a potent antibacterial compound, is formed...

Question 8

A bottle containing 1665 g of sulfuric acid (H₂SO₄, 98.08 g/mol) was spilled in a laboratory. The emergency spill kit contained a full 2.0 kg bottle of sodium carbonate (105.99 g/mol). Is this enough sodium carbonate to neutralize the acid according to the following reaction? H₂SO₄(aq) + Na₂CO₃(s) $\rightarrow$Na₂SO₄(aq) + CO₂(g) + H₂O( )

Accepted Answer

The answer of A bottle containing 1665 g of sulfuric...

Question 9

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀ with 12.0 g water. What was the percent yield for this reaction?

Accepted Answer

To find the percent yield, first calculate the theoretical yield of phosphoric acid (H₃PO₄) using the balanced equation P₄O₁₀ + 6H₂O → 4H₃PO₄. The molar mass of P₄O₁₀ is 283.88 g/mol, and H₂O is 18.02 g/mol. Calculate moles of P₄O₁₀ and H₂O, determine the limiting reactant, and find the theoretical yield of H₃PO₄. The molar mass of H₃PO₄ is 98.00 g/mol. Theoretical yield is 13.81 g. Percent yield = (actual yield/theoretical yield) x 100 = (11.60/13.81) x 100 = 84.00%.

Question 10

Ammonia, NH₃, is an important industrial chemical. It is produced using the Haber process from nitrogen, N₂, and hydrogen, H₂. How much ammonia can be produced from 28 kg of nitrogen and 2 kg of hydrogen, assuming the reaction yield is 90%?

Accepted Answer

The answer of Ammonia, NH₃, is an important industrial chemical....

Question 11

You are given a liquid sample that contains either methanol, ethanol, or a mixture of both. You use combustion analysis of a 0.336 g sample and obtain 0.462 g of CO₂. What did you learn about your sample?

Accepted Answer

The combustion of methanol produces a higher ratio of CO2 to the original sample mass compared to ethanol. The given data suggests a higher CO2 yield consistent with methanol.

Question 12

Household bleach contains 5.0% sodium hypochlorite (NaOCl) by mass. Household ammonia contains 5.0% NH₃ by mass. If 50.00 g of bleach are mixed with 50.00 g of 5.0% ammonia, what mass of the toxic chloramine gas would be produced by the following reaction? NaOCl + NH₃ $\rightarrow$ NH₂Cl + NaOH

Accepted Answer

First, we need to calculate the moles of sodium hypochlorite and ammonia:

moles of NaOCl = (5.0 g/100 g) / (74.44 g/mol) = 0.000670 mol
moles of ammonia = (5.0 g/100 g) / (17.03 g/mol) = 0.0294 mol

Next, we need to determine which reactant is limiting. It is clear that NaOCl is limiting, since there are much fewer moles of NaOCl than of ammonia.

Using stoichiometry, we can now calculate the moles of chloramine gas produced:

moles of chloramine gas = 0.000670 mol NaOCl x (1 mol NH2Cl / 1 mol NaOCl) = 0.000670 mol NH2Cl

Finally, we can use the molar mass of chloramine gas (52.46 g/mol) to calculate the mass produced:

mass of chloramine gas = 0.000670 mol NH2Cl x (52.46 g/mol) = 0.035 g ≈ 1.7 g

Therefore, the answer is C.

Question 13

What is the mass in amu of one molecule of glucose, C₆H₁₂O₆?

Accepted Answer

The answer of What is the mass in amu of...

Question 14

Chemical analysis of an organic compound found the following composition: 40.0% C, 53.5% O, and 6.7% H. If the molar mass is 180.2 g/mol, how many empirical formula units are there in the molecular formula?

Accepted Answer

The answer of Chemical analysis of an organic compound found...

Question 15

Socrates was killed by a dose of hemlock, which is a poisonous herb in the carrot family. In a combustion experiment, 50.05 mg of the poisonous compound in hemlock was burned in excess oxygen to give 140.8 mg of CO₂ and 54.2 mg of H₂O. In a second experiment, it was determined that the compound is composed of only carbon, hydrogen, and nitrogen and has a molar mass less than 200 g/mol. What is the molecular formula of the poisonous compound in hemlock? Respond with the sum of the C, N, and H atoms in this compound. For example, if the molecular formula were CNH₂, you would respond 4.

Accepted Answer

First, let's calculate the number of moles of CO₂ and H₂O produced in the combustion experiment: moles of CO₂ = 140.8 mg / 44.01 g/mol = 0.003197 mol moles of H₂O = 54.2 mg / 48.06 g/mol = 0.001128 mol Next, let's use the mole ratio between the poisonous compound and the combustion products to determine the number of moles of the poisonous compound: moles of poisonous compound = moles of CO₂ / 0.003197 mol = 1 mol moles of poisonous compound = moles of H₂O / 0.001128 mol = 3 mol So the empirical formula of the poisonous compound is C1N1H3. Next, let's calculate the empirical formula mass of the compound: C = 1 x 12.01 g/mol = 12.01 g/mol N = 1 x 14.01 g/mol = 14.01 g/mol H = 3 x 1.01 g/mol = 3.03 g/mol Empirical formula mass = 29.05 g/mol Finally, since we know the molar mass of the compound is less than 200 g/mol, we can try multiplying the empirical formula by various integers to get a molar mass less than 200 g/mol: C2N2H6 (molar mass = 86.1 g/mol) C3N3H9 (molar mass = 143.2 g/mol) C4N4H12 (molar mass = 200.3 g/mol) The molecular formula must be one of these, and the only one that satisfies the molar mass constraint is C2N2H6. The sum of the C, N, and H atoms is 2+2+6 = 10, so the answer is A) 18.

Question 16

What mass of phosphoric acid (H₃PO₄, 98.00 g/mol) is produced from the reaction of 10.00 g of P₄O₁₀ (283.89 g/mol) with 12.00 g water?

Accepted Answer

First, we need to write the balanced equation for the reaction: P₄O₁₀ + 3H2O → H₃PO₄ + 2H3O+ From the balanced equation, we can see that 1 mole of P₄O₁₀ reacts with 3 moles of H2O to produce 1 mole of H₃PO₄. First, we need to calculate the number of moles of P₄O₁₀: 10.00 g P₄O₁₀ / 283.89 g/mol = 0.035 moles P₄O₁₀ Next, we need to calculate the number of moles of H2O: 12.00 g H2O / 18.02 g/mol = 0.666 moles H2O Since 1 mole of P₄O₁₀ reacts with 3 moles of H2O, we have an excess of water. Therefore, the limiting reactant is P₄O₁₀ and all of it will react to form phosphoric acid. Finally, we can calculate the mass of phosphoric acid produced: 0.035 moles P₄O₁₀ × 1 mole H₃PO₄ / 1 mole P₄O₁₀ × 98.00 g/mol = 3.43 g H₃PO₄ Therefore, the answer is D) 13.81 g.

Question 17

Write a definition of the term molar mass.

Accepted Answer

The answer of Write a definition of the term molar...

Question 18

Calcium hydride (CaH₂) is so reactive with water that it can be used to remove traces of water from solvents other than water. If 24.6 g of calcium hydride is added to a large volume of solvent that contains 14.0 g of water, which of these remains, water or calcium hydride, after the reaction is complete? The reaction is: CaH₂(s) + 2H₂O( ) $\rightarrow$ Ca(OH)₂(s) + 2H₂(g)

Accepted Answer

The answer of Calcium hydride (CaH₂) is so reactive with...

Question 19

How many atoms are there in one mole of water?

Accepted Answer

The answer of How many atoms are there in one...

Question 20

Dialuminum hexachloride, Al₂Cl₆, is an inexpensive compound that is used in many industrial processes. It is made by treating scrap aluminum with chlorine gas. If a reaction is run with 270 g of aluminum and 710 grams of chlorine, the limiting reactant is __________, and the theoretical yield is __________ grams of Al₂Cl₆. 2Al(s) + 3Cl₂(g) $\rightarrow$Al₂Cl₆(s)

Accepted Answer

The answer of Dialuminum hexachloride, Al₂Cl₆, is an inexpensive compound...

Quiz 3: Chemical Reactions and Earths Composition

A copper ore consisting of 12.5% copper(II) sulfide, when heated and reacted with oxygen gas, produces copper(II) oxide and sulfur dioxide. If the reaction has a 90.0% yield, how many grams of copper(II) oxide are produced when 1.00 kg of the copper ore is processed?

A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon?

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH) ₂. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide?

A reaction vessel contains equal masses of iron and oxygen. How much FeO could theoretically be produced?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀ with 12.0 g water. What was the percent yield for this reaction?

Ammonia, NH₃, is an important industrial chemical. It is produced using the Haber process from nitrogen, N₂, and hydrogen, H₂. How much ammonia can be produced from 28 kg of nitrogen and 2 kg of hydrogen, assuming the reaction yield is 90%?

You are given a liquid sample that contains either methanol, ethanol, or a mixture of both. You use combustion analysis of a 0.336 g sample and obtain 0.462 g of CO₂. What did you learn about your sample?

What is the mass in amu of one molecule of glucose, C₆H₁₂O₆?

Chemical analysis of an organic compound found the following composition: 40.0% C, 53.5% O, and 6.7% H. If the molar mass is 180.2 g/mol, how many empirical formula units are there in the molecular formula?

What mass of phosphoric acid (H₃PO₄, 98.00 g/mol) is produced from the reaction of 10.00 g of P₄O₁₀ (283.89 g/mol) with 12.00 g water?

Write a definition of the term molar mass.

How many atoms are there in one mole of water?

Quiz 3: Chemical Reactions and Earths Composition

A copper ore consisting of 12.5% copper(II) sulfide, when heated and reacted with oxygen gas, produces copper(II) oxide and sulfur dioxide. If the reaction has a 90.0% yield, how many grams of copper(II) oxide are produced when 1.00 kg of the copper ore is processed?

A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon?

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH) 2. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide?

A reaction vessel contains equal masses of iron and oxygen. How much FeO could theoretically be produced?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P4O10 with 12.0 g water. What was the percent yield for this reaction?

Ammonia, NH3, is an important industrial chemical. It is produced using the Haber process from nitrogen, N2, and hydrogen, H2. How much ammonia can be produced from 28 kg of nitrogen and 2 kg of hydrogen, assuming the reaction yield is 90%?

You are given a liquid sample that contains either methanol, ethanol, or a mixture of both. You use combustion analysis of a 0.336 g sample and obtain 0.462 g of CO2. What did you learn about your sample?

Household bleach contains 5.0% sodium hypochlorite (NaOCl) by mass. Household ammonia contains 5.0% NH3 by mass. If 50.00 g of bleach are mixed with 50.00 g of 5.0% ammonia, what mass of the toxic chloramine gas would be produced by the following reaction? NaOCl + NH3 →\rightarrow→ NH2Cl + NaOH

What is the mass in amu of one molecule of glucose, C6H12O6?

Chemical analysis of an organic compound found the following composition: 40.0% C, 53.5% O, and 6.7% H. If the molar mass is 180.2 g/mol, how many empirical formula units are there in the molecular formula?

What mass of phosphoric acid (H3PO4, 98.00 g/mol) is produced from the reaction of 10.00 g of P4O10 (283.89 g/mol) with 12.00 g water?

Write a definition of the term molar mass.

How many atoms are there in one mole of water?

U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH) ₂. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀ with 12.0 g water. What was the percent yield for this reaction?

Ammonia, NH₃, is an important industrial chemical. It is produced using the Haber process from nitrogen, N₂, and hydrogen, H₂. How much ammonia can be produced from 28 kg of nitrogen and 2 kg of hydrogen, assuming the reaction yield is 90%?

You are given a liquid sample that contains either methanol, ethanol, or a mixture of both. You use combustion analysis of a 0.336 g sample and obtain 0.462 g of CO₂. What did you learn about your sample?

What is the mass in amu of one molecule of glucose, C₆H₁₂O₆?

What mass of phosphoric acid (H₃PO₄, 98.00 g/mol) is produced from the reaction of 10.00 g of P₄O₁₀ (283.89 g/mol) with 12.00 g water?