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

Beryllium metal reacts with chlorine gas to produce beryllium chloride (BeCl₂). Given the following diagram of available beryllium atoms and chlorine molecules in a reaction flask, identify the excess reagent and how many atoms/molecules of reactant remain at the end of the reaction.

Accepted Answer

There are two beryllium atoms and one chlorine molecule available, indicating that beryllium is the limiting reagent and chlorine is in excess. Therefore, there will be one beryllium atom remaining at the end of the reaction. The chlorine molecule will completely react with the available beryllium atoms to produce one molecule of beryllium chloride.

Question 3

At the Tesla automotive factory, a Model S sedan is built using 4 tires, a main chassis, and 5 lithium ion batteries. How many sedans can be made if there are 17 tires, 5 chassis, and 22 batteries?

Accepted Answer

To make 1 sedan, it requires 4 tires, 1 main chassis, and 5 lithium ion batteries.
Therefore, with the given resources, we can make the following number of sedans:
- Tires: 17 / 4 = 4 (rounding down to nearest whole number)
- Chassis: 5 / 1 = 5
- Batteries: 22 / 5 = 4 (rounding down to nearest whole number)
The limiting factor is the number of batteries, as we can only make 4 sedans with the given 22 batteries. Therefore, the answer is C) 4.

Question 4

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

To calculate percent yield, we need to compare the actual yield to the theoretical yield. The theoretical yield is the amount of product that should be obtained based on stoichiometry and assuming a 100% conversion.

1 mole of Ca(OH)2 produces 1 mole of CaO. The molar mass of Ca(OH)2 is approximately 74 g/mol, so 1 mole is equal to 74 grams.

Therefore, the theoretical yield of CaO from 74 grams of Ca(OH)2 would be 74 grams.

However, the actual yield is only 45 grams.

percent yield = (actual yield/theoretical yield) x 100%
percent yield = (45/74) x 100% = 60.8%

So, the closest answer choice is B, 80%.

Question 5

A reaction vessel contains equal masses of solid magnesium metal and oxygen gas. The mixture is ignited and burns with a burst of light and heat, producing solid MgO. The mass of the MgO is less than the initial mass of the magnesium and oxygen. What is your explanation for this apparent loss of mass?

Accepted Answer

The answer of A reaction vessel contains equal masses of...

Question 6

At Sal's Sandwich Shop, a regular club sub is made using 2 slices of bread, 3 pieces of meat, and 1 cheese slice. How many club sandwiches can be made if there are 7 slices of bread, 10 pieces of meat, and 5 cheese slices?

Accepted Answer

The limiting factor in this scenario is the number of cheese slices. With only 5 cheese slices, we can make a maximum of 5 club sandwiches. However, we have enough bread and meat to make more than 5 sandwiches, which means that we are restricted by the cheese slices. Therefore, the answer is B)3.

Question 7

Write a definition of the term molar mass.

Accepted Answer

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

Question 8

In which of the following reaction mixtures, where A reacts with B in the following balanced equation, is B the limiting reactant? A 2B AB₂

Accepted Answer

The answer of In which of the following reaction mixtures,...

Question 9

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 10

How many total atoms are there in one mole of water?

Accepted Answer

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

Question 11

In a self-contained breathing apparatus, potassium superoxide, KO₂, reacts with carbon dioxide to form potassium carbonate and oxygen. Identify the limiting reactant and determine the amount of oxygen gas, in moles, that can be produced from 250 g of KO₂ and 450 g of CO₂. 4KO₂(s) 2CO₂(g) 2K₂CO₃(s) 3O₂(g)

Accepted Answer

The answer of In a self-contained breathing apparatus, potassium superoxide,...

Question 12

For movie night, Annabelle popped two bags of popcorn. In Bag 1, 654 of a possible 1,213 kernels popped. In Bag 2, 343 of 690 kernels popped. Identify the bag with the highest popcorn yield and report this percent yield.

Accepted Answer

To determine the percent yield of each bag, we need to divide the number of kernels popped by the total number of kernels in each bag, then multiply by 100 to get a percentage.

For Bag 1: 
Percent yield = (654/1213) x 100 = 53.9%

For Bag 2: 
Percent yield = (343/690) x 100 = 49.7%

Therefore, Bag 1 has the highest popcorn yield with a percentage of 53.9%. The answer is B.

Question 13

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(l) Ca(OH)₂(s) 2H₂(g)

Accepted Answer

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

Question 14

A bottle containing 1,665 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) Na₂SO₄(aq) CO₂(g) H₂O(l)

Accepted Answer

The answer of A bottle containing 1,665 g of sulfuric...

Question 15

Dialuminum hexachloride, Al₂Cl₆ (266.66 g/mol), 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 ________ of Al₂Cl₆. 2Al(s) 3Cl₂(g) Al₂Cl₆(s)

Accepted Answer

First, we need to determine the limiting reactant by converting the given masses into moles.

270 g Al x (1 mol Al/26.98 g Al) = 10.01 mol Al 
710 g Cl2 x (1 mol Cl2/70.91 g Cl2) = 9.99 mol Cl2

Since aluminum has a higher number of moles, it is not the limiting reactant. The moles of Cl2 are slightly less than the moles of Al, so Cl2 is the limiting reactant.

To find the theoretical yield, we need to use stoichiometry to determine the amount of product that can be formed from the limiting reactant. The balanced chemical equation tells us that 2 moles of Al react with 3 moles of Cl2 to produce 2 moles of Al2Cl6.

9.99 mol Cl2 x (2 mol Al2Cl6/3 mol Cl2) x (266.66 g Al2Cl6/1 mol Al2Cl6) = 890 g Al2Cl6

Therefore, the answer is B) Cl2; 890g.

Question 16

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 NH₂Cl NaOH

Accepted Answer

The answer of Household bleach contains 5.0% sodium hypochlorite (NaOCl)...

Question 17

One reaction that occurs during the deployment of an air bag is shown below, where sodium metal reacts with potassium nitrate. If 5.10 g of sodium and 305 g of potassium nitrate react in an airbag, how many grams of KNO₃ remain because of the limited amount of sodium present? 10Na(s) 2KNO₃(s) K₂O(s) 5Na₂O(s) N₂(g)

Accepted Answer

The answer of One reaction that occurs during the deployment...

Question 18

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 balanced chemical equation for the Haber process is:N2 + 3H2 → 2NH3From the stoichiometry of the reaction, we can see that 1 mole of nitrogen reacts with 3 moles of hydrogen to produce 2 moles of ammonia.The molar mass of nitrogen is 28 g/mol, and the molar mass of hydrogen is 2 g/mol. Therefore, 28 kg of nitrogen is equal to 28000 g / 28 g/mol = 1000 mol of nitrogen, and 2 kg of hydrogen is equal to 2000 g / 2 g/mol = 1000 mol of hydrogen.According to the stoichiometry of the reaction, 1000 mol of nitrogen will react with 3000 mol of hydrogen to produce 2000 mol of ammonia. However, the reaction yield is only 90%, which means that only 90% of the theoretical yield of ammonia will be produced. Therefore, the actual yield of ammonia will be 2000 mol * 0.9 = 1800 mol.The molar mass of ammonia is 17 g/mol. Therefore, 1800 mol of ammonia is equal to 1800 mol * 17 g/mol = 30600 g = 30.6 kg.Therefore, the correct answer is A) 10.2 kg.

Question 19

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀with 12.00 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 stoichiometry. The balanced equation is P₄O₁₀ + 6H₂O → 4H₃PO₄. Calculate moles of P₄O₁₀ and H₂O, find the limiting reactant, and use it to find the theoretical yield of H₃PO₄. Then, percent yield = (actual yield/theoretical yield) × 100%. The calculations show that the percent yield is 84.00%.

Question 20

What is the molar mass of glucose, C₆H₁₂O₆?

Accepted Answer

The answer of What is the molar mass of glucose,...

Quiz 3: Stoichiometry: Mass, Formulas, and Reactions

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?

Beryllium metal reacts with chlorine gas to produce beryllium chloride (BeCl₂) . Given the following diagram of available beryllium atoms and chlorine molecules in a reaction flask, identify the excess reagent and how many atoms/molecules of reactant remain at the end of the reaction.

At the Tesla automotive factory, a Model S sedan is built using 4 tires, a main chassis, and 5 lithium ion batteries. How many sedans can be made if there are 17 tires, 5 chassis, and 22 batteries?

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?

At Sal's Sandwich Shop, a regular club sub is made using 2 slices of bread, 3 pieces of meat, and 1 cheese slice. How many club sandwiches can be made if there are 7 slices of bread, 10 pieces of meat, and 5 cheese slices?

Write a definition of the term molar mass.

In which of the following reaction mixtures, where A reacts with B in the following balanced equation, is B the limiting reactant? A 2B AB₂

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?

How many total atoms are there in one mole of water?

For movie night, Annabelle popped two bags of popcorn. In Bag 1, 654 of a possible 1,213 kernels popped. In Bag 2, 343 of 690 kernels popped. Identify the bag with the highest popcorn yield and report this percent yield.

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 NH₂Cl NaOH

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%?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀with 12.00 g water. What was the percent yield for this reaction?

What is the molar mass of glucose, C₆H₁₂O₆?

Quiz 3: Stoichiometry: Mass, Formulas, and Reactions

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?

Beryllium metal reacts with chlorine gas to produce beryllium chloride (BeCl2) . Given the following diagram of available beryllium atoms and chlorine molecules in a reaction flask, identify the excess reagent and how many atoms/molecules of reactant remain at the end of the reaction.

At the Tesla automotive factory, a Model S sedan is built using 4 tires, a main chassis, and 5 lithium ion batteries. How many sedans can be made if there are 17 tires, 5 chassis, and 22 batteries?

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?

At Sal's Sandwich Shop, a regular club sub is made using 2 slices of bread, 3 pieces of meat, and 1 cheese slice. How many club sandwiches can be made if there are 7 slices of bread, 10 pieces of meat, and 5 cheese slices?

Write a definition of the term molar mass.

In which of the following reaction mixtures, where A reacts with B in the following balanced equation, is B the limiting reactant? A 2B AB2

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?

How many total atoms are there in one mole of water?

For movie night, Annabelle popped two bags of popcorn. In Bag 1, 654 of a possible 1,213 kernels popped. In Bag 2, 343 of 690 kernels popped. Identify the bag with the highest popcorn yield and report this percent yield.

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 NH2Cl NaOH

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%?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P4O10 with 12.00 g water. What was the percent yield for this reaction?

What is the molar mass of glucose, C6H12O6?

Beryllium metal reacts with chlorine gas to produce beryllium chloride (BeCl₂) . Given the following diagram of available beryllium atoms and chlorine molecules in a reaction flask, identify the excess reagent and how many atoms/molecules of reactant remain at the end of the reaction.

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?

In which of the following reaction mixtures, where A reacts with B in the following balanced equation, is B the limiting reactant? A 2B AB₂

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?

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 NH₂Cl NaOH

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%?

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀with 12.00 g water. What was the percent yield for this reaction?

What is the molar mass of glucose, C₆H₁₂O₆?