Q: Which of the following is the correct balanced equation for the preparation of ammonium carbonate, $$(\text{NH}_4)_2\text{CO}_3$$, from ammonia, carbon dioxide, and water?

$$2\text{NH}_3 + \text{CO}_2 + \text{H}_2\text{O} \rightarrow (\text{NH}_4)_2\text{CO}_3$$

Question 1

Which of the following statements about the limiting reactant in a chemical reaction is TRUE?

Accepted Answer

The limiting reactant is completely consumed first and determines the maximum amount of product formed.

Question 2

Given the reaction: $$2	ext{Na} + 	ext{Cl}_2 ightarrow 2	ext{NaCl}$$, how many moles of chlorine gas are needed to produce 0.5 moles of sodium chloride?

Accepted Answer

$$0.25$$ moles

Question 3

Which of the following is a correct definition of percent yield?

Accepted Answer

Percent yield is the ratio of the actual yield to the theoretical yield, multiplied by 100.

Question 4

Suppose you have 2.5 moles of HCl and 1.4 moles of Ca(OH)$$_2$$ for the reaction: $$2	ext{HCl} + 	ext{Ca(OH)}_2 ightarrow 2	ext{H}_2	ext{O} + 	ext{CaCl}_2. $$How many moles of CaCl$$_2$$ can be theoretically produced?

Accepted Answer

1.25 moles

Question 5

A sample of $$8.5 g NH$_3 on $$oxidation produces $$4.5 g of NO. $$Calculate the percent yield for the reaction: $$4	ext{NH}_3 + 5	ext{O}_2 ightarrow 4	ext{NO} + 6	ext{H}_2	ext{O}.$$

Accepted Answer

$$75\%$$

Question 6

Which of the following statements about global warming is FALSE?

Accepted Answer

If the level of greenhouse gases increases, the temperature will decrease.

Question 7

Given the reaction: $$2	ext{Al} + 3	ext{O}_2 ightarrow 2	ext{Al}_2	ext{O}_3$$, how many grams of aluminum oxide are produced from $$10.0$$ grams of Al and $$19.0$$ grams of O$$_2$$?

Accepted Answer

$$18.0 g$$

Question 8

Which of the following is the correct formula for the carbonate ion?

Accepted Answer

$$	ext{CO}_3$$^{2-}$$

Question 9

If you start with $$4$$ moles of KClO$$_3 in $$the reaction $$2	ext{KClO}_3 ightarrow 2	ext{KCl} + 3	ext{O}_2$$, how many moles of O$$_2$$ can be produced?

Accepted Answer

$$6$$ moles

Question 10

Which ingredient is the limiting reactant if you have 5 cups of flour, 9 eggs, and 3 lbs of oil, given the recipe: 2 cups flour + 3 eggs + 1 lb oil = 4 waffles?

Accepted Answer

Eggs

Question 11

Consider the reaction: $$2	ext{Na}_3	ext{PO}_4 + 3	ext{Ca(NO}_3)_2 ightarrow 6	ext{NaNO}_3 + 	ext{Ca}_3(	ext{PO}_4)_2. If $$you have $$3.4$$ moles of Ca(NO$$_3$$)$$_2$$ and $$2.4$$ moles of Na$$_3PO$_4$$, which is the limiting reactant?

Accepted Answer

Na$$_3PO$_4$$

Question 12

Calculate the amount of heat ($$\Delta H) $$associated with the complete reaction of $$8.0 g of H$_2$$ for the reaction: $$	ext{CO} + 2	ext{H}_2 ightarrow 	ext{CH}_3	ext{OH}$$, $$\Delta H = -128 kJ.$$

Accepted Answer

$$-256 kJ$$

Question 13

Which of the following is the correct formula for the ammonium ion?

Accepted Answer

$$	ext{NH}_4^+$$

Question 14

A reaction has a theoretical yield of $$75.0$$ grams of product, but the actual yield is $$42.0$$ grams. What is the percent yield?

Accepted Answer

$$56\%$$

Question 15

Which of the following is the correct balanced equation for the preparation of ammonium carbonate, $$(	ext{NH}_4)_2	ext{CO}_3$$, from ammonia, carbon dioxide, and water?

Accepted Answer

$$2	ext{NH}_3 + 	ext{CO}_2 + 	ext{H}_2	ext{O} ightarrow (	ext{NH}_4)_2	ext{CO}_3$$

Question 16

If you start with $$10.0 g of Al $$and $$19.0 g of O$_2$$ for the reaction $$4	ext{Al} + 3	ext{O}_2 ightarrow 2	ext{Al}_2	ext{O}_3$$, how many grams of the excess reactant are left over after the reaction is complete?

Accepted Answer

$$8.7 g$$

Question 17

Which of the following is the correct formula for the sulfate ion?

Accepted Answer

$$	ext{SO}_4$$^{2-}$$

Question 18

Which of the following choices would result in the greatest amount of ammonium carbonate being formed?

Accepted Answer

React 2 moles NH$$_3$$, 2 moles CO$$_2$$, and 1 mole H$$_2O$$

Question 19

Which of the following is the correct formula for the phosphate ion?

Accepted Answer

$$	ext{PO}_4$$^{3-}$$

Quantities in Chemical Reactions: Stoichiometry, Limiting Reactants, and Percent Yield

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