Question 1

Which of the following is the correct balanced chemical equation for the rusting of iron in the presence of oxygen and water?

Accepted Answer

$$4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3$$

Question 2

During the fermentation of sugar ($$C_6H_{12}O_6$) by yeast, which of the following is the correct balanced equation for the reaction?

Accepted Answer

$$C_6H_{12}O_6$ \rightarrow 2C_2H_5OH + 2CO_2$$

Question 3

What is the balanced chemical equation for the combustion of ethanol ($$C_2H_5OH$$)?

Accepted Answer

$$C_2H_5OH + 3O_2 \rightarrow 2CO_2 + 3H_2O$$

Question 4

Given the reaction $$3NH_4 \rightarrow 4NH_3 + N_2$, how many moles of NH_3$ are produced when 2.6 mol of NH_4$ completely reacts?

Accepted Answer

$$3.47$$ mol

Question 5

If 65.3 g of $$NH_4 is $$used in the reaction $$3NH_4 \rightarrow 4NH_3 + N_2$, how many grams of NH_3$ are produced? (Molar mass: NH_4$ = 18.04 g/$$mol, $$NH_3 = 17.03$ g/mol)

Accepted Answer

$$82.4 g$$

Question 6

Which of the following is the correct balanced equation for the reaction between iron(II) bromide and bromine?

Accepted Answer

$$2FeBr_2 + Br_2$ \rightarrow 2FeBr_3$$

Question 7

How many grams of $$FeBr_2$$ are needed to dissolve $$3.2 g of $$pure bromine ($$Br_2) in $$the reaction $$2FeBr_2 + Br_2$ \rightarrow 2FeBr_3$$? (Molar masses: $$FeBr_2 = 215.65$ g/mol, Br_2$ = 159.8 g/$$mol)

Accepted Answer

$$8.63 g$$

Question 8

What is the limiting reactant if 16 mol of Al react with 13 mol of $$O_2 in $$the reaction $$4Al + 3O_2 \rightarrow 2Al_2O_3$$?

Accepted Answer

$$O_2$$

Question 9

When $$28.5 g$$ $$KCl is $$added to a solution containing $$25.7 g$$ $$Pb(NO_3$)_2$$, $$PbCl_2$$ precipitate forms. What is the theoretical yield of $$PbCl_2 in $$grams? (Molar masses: $$KCl = 74.55 g/$$mol, $$Pb(NO_3$)_2 = 331.2 g/$$mol, $$PbCl_2 = 278.1$ g/mol)

Accepted Answer

$$21.6 g$$

Question 10

Write the balanced chemical equation for the reaction between potassium chloride and lead(II) nitrate.

Accepted Answer

$$Pb(NO_3$)_2 + 2KCl \rightarrow $$PbCl_2$$ + 2KNO_3$$

Question 11

A student mixes $$10.0 g of$$ $$Al$$ with $$20.0 g of$$ $$O_2 to $$produce $$Al_2O_3. $$Which reactant is limiting and how many grams of $$Al_2O_3$$ are produced? (Molar masses: $$Al = 26.98 g/$$mol, $$O_2 = 32.00$ g/mol, Al_2O_3 = 101.96$ g/mol)

Accepted Answer

O$$_2 is $$limiting; $$15.9 g$$ $$Al_2O_3$$ produced

Question 12

Which of the following is the correct balanced equation for the reaction between metallic sodium and chlorine gas?

Accepted Answer

$$2Na + Cl_2$ \rightarrow 2NaCl$$

Question 13

If $$5.0 g of$$ $$Na$$ reacts with excess $$Cl_2$$, how many grams of $$NaCl$$ are produced? (Molar masses: $$Na = 22.99 g/$$mol, $$NaCl = 58.44 g/$$mol)

Accepted Answer

$$12.7 g$$

Question 14

A chemical reaction produces $$4.88 kg of$$ $$NH_3$$ from $$NH_4. $$How many moles of $$NH_3 is $$this? (Molar mass $$NH_3 = 17.03$ g/mol)

Accepted Answer

$$287$$ mol

Question 15

In the reaction $$2FeBr_2 + Br_2$ \rightarrow 2FeBr_3$$, what is the mole ratio of $$FeBr_2 to$$ $$FeBr_3$$?

Accepted Answer

$$1:1$$

Question 16

Which of the following statements best describes a limiting reactant in a chemical reaction?

Accepted Answer

It is the reactant that is completely consumed first, limiting the amount of product formed.

Question 17

A student wants to produce $$50.0 g of$$ $$PbCl_2 by $$reacting $$KCl$$ and $$Pb(NO_3$)_2. $$What is the minimum mass of $$KCl$$ required? (Molar masses: $$PbCl_2 = 278.1$ g/mol, $$KCl = 74.55$$ g/mol)

Accepted Answer

$$26.8 g$$

Question 18

Which of the following is a real-world example of a precipitation reaction?

Accepted Answer

Formation of kidney stones from calcium oxalate in urine

Question 19

In the reaction $$C_6H_{12}O_6$ \rightarrow 2C_2H_5OH + 2CO_2$$, what is the percent yield if $$10.0 g of$$ $$C_6H_{12}O_6$ produces 4.0$ g of C_2H_5OH$? (Molar masses: C_6H$$_{12}$$O_6 = 180.16$ g/mol, C_2H_5OH = 46.07$ g/mol)

Accepted Answer

$$77.2\%$$

Stoichiometry and Chemical Reactions: Study Notes for General Chemistry

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