Question 1

Given the unbalanced reaction:

$$\mathrm{P} + \mathrm{Cl}_2 \rightarrow \mathrm{PCl}_3$$

How many moles of $$\mathrm{Cl}_2$$ are required to produce 11.6 moles of $$\mathrm{PCl}_3$$ after balancing the equation?

Accepted Answer

17.4 moles

Question 2

Urea $$((\mathrm{NH}_2)_2\mathrm{CO})$$ reacts with water to produce ammonia and carbon dioxide:

$$(\mathrm{NH}_2)_2\mathrm{CO} + \mathrm{H}_2\mathrm{O} \rightarrow 2\ \mathrm{NH}_3 + \mathrm{CO}_2$$

How many grams of $$\mathrm{CO}_2$$ are produced from 0.83 mole of urea?

Accepted Answer

$$14.6\ \mathrm{g}$$

Question 3

In the reaction $$\mathrm{N}_2 + 3\ \mathrm{H}_2 \rightarrow 2\ \mathrm{NH}_3$$, how many grams of $$\mathrm{N}_2$$ are required to produce $$7.5\ \mathrm{g} of$$ $$\mathrm{NH}_3$$?

Accepted Answer

$$6.18\ \mathrm{g}$$

Question 4

Solid lithium hydroxide is used in spacecraft to remove exhaled $$\mathrm{CO}_2 by $$the reaction:

$$2\ \mathrm{LiOH} (s) + \mathrm{CO}_2 (g) \rightarrow \mathrm{Li}_2\mathrm{CO}_3 (s) + \mathrm{H}_2\mathrm{O} (l)$$

What mass (in grams) of $$\mathrm{CO}_2$$ can be absorbed by $$1.00\ \mathrm{kg} of$$ $$\mathrm{LiOH}$$?

Accepted Answer

$$769\ \mathrm{g}$$

Question 5

Methanol is produced by the reaction:

$$2\ \mathrm{H}_2 (g) + \mathrm{CO} (g) ightarrow \mathrm{CH}_3\mathrm{OH} (l)

If$$ $$8.60 	imes 10^3$\ \mathrm{g} of$$ $$\mathrm{H}_2 is $$reacted and $$3.57 	imes 10^4$\ \mathrm{g} of$$ $$\mathrm{CH}_3\mathrm{OH} is $$actually produced, what is the percent yield of methanol?

Accepted Answer

$$90.0\%$$

Question 6

If $$18.1\ \mathrm{g} of$$ $$\mathrm{NH}_3 is $$reacted with $$90.4\ \mathrm{g} of$$ $$\mathrm{CuO} in $$the reaction:

$$2\ \mathrm{NH}_3 + 3\ \mathrm{CuO} \rightarrow \mathrm{N}_2 + 3\ \mathrm{Cu} + 3\ \mathrm{H}_2\mathrm{O}$$

How many grams of $$\mathrm{N}_2$$ will be formed?

Accepted Answer

$$10.4\ \mathrm{g}$$

Question 7

A patient is exposed to $$44.0\ \mathrm{g} of$$ $$\mathrm{CO}_2. $$How many moles of $$\mathrm{LiOH}$$ are required to absorb all the $$\mathrm{CO}_2$$ according to the reaction:

$$2\ \mathrm{LiOH} + \mathrm{CO}_2 \rightarrow \mathrm{Li}_2\mathrm{CO}_3 + \mathrm{H}_2\mathrm{O}$$

Accepted Answer

2.00 moles

Question 8

In the synthesis of ammonia:

$$\mathrm{N}_2 + 3\ \mathrm{H}_2 \rightarrow 2\ \mathrm{NH}_3

If $$you start with $$10.0\ \mathrm{g} of$$ $$\mathrm{N}_2$$ and $$10.0\ \mathrm{g} of$$ $$\mathrm{H}_2$$, which reactant is the limiting reagent?

Accepted Answer

$$\mathrm{H}_2$$

Question 9

If $$0.83$$ mole of urea $$((\mathrm{NH}_2)_2\mathrm{CO}) is $$completely reacted, how many grams of $$\mathrm{NH}_3$$ are produced?

$$(\mathrm{NH}_2)_2\mathrm{CO} + \mathrm{H}_2\mathrm{O} \rightarrow 2\ \mathrm{NH}_3 + \mathrm{CO}_2$$

Accepted Answer

$$28.2\ \mathrm{g}$$

Question 10

A race car uses methanol ($$\mathrm{CH}_3\mathrm{OH}) as $$fuel. If $$2.00\ \mathrm{mol} of$$ $$\mathrm{CO} is $$available, what is the maximum mass of methanol that can be produced?

$$2\ \mathrm{H}_2 + \mathrm{CO} \rightarrow \mathrm{CH}_3\mathrm{OH}$$

Accepted Answer

$$32.0\ \mathrm{g}$$

Question 11

In the reaction $$2\ \mathrm{NH}_3 + 3\ \mathrm{CuO} \rightarrow \mathrm{N}_2 + 3\ \mathrm{Cu} + 3\ \mathrm{H}_2\mathrm{O}$$, what is the theoretical yield of $$\mathrm{N}_2 (in $$grams) if $$34.0\ \mathrm{g} of$$ $$\mathrm{NH}_3 is $$used with excess $$\mathrm{CuO}$$?

Accepted Answer

$$28.0\ \mathrm{g}$$

Question 12

Which of the following best describes the role of $$\mathrm{LiOH} in $$spacecraft life support systems?

Accepted Answer

It absorbs $$\mathrm{CO}_2 by $$forming $$\mathrm{Li}_2\mathrm{CO}_3$$ and $$\mathrm{H}_2\mathrm{O}.$$

Question 13

If $$5.00\ \mathrm{mol} of$$ $$\mathrm{H}_2$$ reacts with excess $$\mathrm{CO}$$, how many moles of $$\mathrm{CH}_3\mathrm{OH}$$ can be produced?

$$2\ \mathrm{H}_2 + \mathrm{CO} \rightarrow \mathrm{CH}_3\mathrm{OH}$$

Accepted Answer

2.50 moles

Question 14

A chemist wants to produce $$20.0\ \mathrm{g} of$$ $$\mathrm{NH}_3. $$What mass of $$\mathrm{N}_2 is $$required?

$$\mathrm{N}_2 + 3\ \mathrm{H}_2 \rightarrow 2\ \mathrm{NH}_3$$

Accepted Answer

$$16.5\ \mathrm{g}$$

Question 15

If $$1.00\ \mathrm{kg} of$$ $$\mathrm{LiOH} is $$available, what is the maximum mass of $$\mathrm{Li}_2\mathrm{CO}_3$$ that can be produced?

$$2\ \mathrm{LiOH} + \mathrm{CO}_2 \rightarrow \mathrm{Li}_2\mathrm{CO}_3 + \mathrm{H}_2\mathrm{O}$$

Accepted Answer

$$1.04\ \mathrm{kg}$$

Question 16

Which of the following statements about limiting reactants is correct?

Accepted Answer

The limiting reactant is the one that produces the least amount of product.

Question 17

In the reaction $$2\ \mathrm{NH}_3 + 3\ \mathrm{CuO} \rightarrow \mathrm{N}_2 + 3\ \mathrm{Cu} + 3\ \mathrm{H}_2\mathrm{O}$$, if $$0.500\ \mathrm{mol} of$$ $$\mathrm{NH}_3$$ and $$0.500\ \mathrm{mol} of$$ $$\mathrm{CuO}$$ are mixed, what is the limiting reactant?

Accepted Answer

$$\mathrm{CuO}$$

Question 18

A reaction has a theoretical yield of $$40.0\ \mathrm{g}$$ but only $$32.0\ \mathrm{g} of $$product is obtained. What is the percent yield?

Accepted Answer

$$80.0\%$$

Question 19

Which of the following best explains why stoichiometry is important in industrial chemical processes?

Accepted Answer

It allows for the calculation of reactant quantities to maximize product yield and minimize waste.

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