COPY: 9 Holt Stoichiometry: Calculating Quantities in Reactions

In a chemical reaction, what information is conveyed by the coefficients in a balanced equation?

Which of the options describes the role of mole ratios in stoichiometry?

What is the first step in solving stoichiometry problems?

How does molar mass relate mass to moles of a substance?

If you are given the volume of a liquid reactant, what additional information is needed to determine the number of moles of the reactant?

If a substance in a stoichiometry problem is a gas at standard temperature and pressure (STP), which conversion factor is most appropriate to use for converting volume to moles?

In a balanced chemical equation, $2C_8H_{18}(g) + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$, what is the mole ratio of $O_2$ to $CO_2$?

Consider the following reaction: $N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)$. If you have 6 moles of $H_2$, how many moles of $NH_3$ can be produced?

How many grams of NaCl are needed to make 500 mL of a 0.100 M NaCl solution? (Molar mass of NaCl = 58.44 g/mol)

In the reaction $2H_2 + O_2 \rightarrow 2H_2O$, if 4.0 g of $H_2$ reacts with excess $O_2$, what mass of $H_2O$ is produced? (Molar mass: $H_2$ = 2.02 g/mol, $H_2O$ = 18.02 g/mol)

In a chemical reaction, what is the limiting reactant?

What is the excess reactant in a chemical reaction?

Which of the options describes theoretical yield?

What is the correct definition of actual yield?

Which of the options is the correct formula for calculating percentage yield?

In the reaction $A + 2B \rightarrow C$, if 10.0 g of A (molar mass 50.0 g/mol) reacts with 10.0 g of B (molar mass 25.0 g/mol), which is the limiting reactant?

For the reaction in the previous question ($A + 2B \rightarrow C$), if the actual yield of C is 8.0 g, and the theoretical yield is 10.0 g, calculate the percentage yield.

In industrial processes, why might a cheaper reactant be used as the excess reactant?

Which of the following factors may cause the actual yield of a reaction to be less than the theoretical yield?

What is the main purpose of air bags in vehicles?

Why is stoichiometry important in the design of air bags?

What is the primary gas used to inflate air bags in most vehicles?

Many air bags use a mixture of sodium azide ($NaN_3$) and an oxidizer. What is the purpose of the oxidizer?

Why is it important to have the correct fuel-air ratio in an engine?

When an engine is described as 'flooded', what is the issue?

Automobile exhaust contains nitrogen oxides ($NO_x$). How are these compounds formed?

Regarding pollution control in modern automobiles, what is the role of a catalytic converter?

Commonly, what metals are used as catalysts in catalytic converters?

What is the effect of water dripping from a car’s tailpipe shortly after the automobile first starts running?

In air bag stoichiometry, given a car that contains 2NaN3(s) that produces 3 mol N2(g), what volume of N2 is produced when 1 mol of NaN3 is reacted? (Molar volume of a gas @STP = 22.41L)

Within stoichiometry, the fuel-air ratio is critical to maximize efficiency, in the following reaction, what is the resulting H20 product when 6 moles of C8H18 are reacted with 75 moles of O2?

If too little air is incorporated within the running engine, which of the following are potential results?

Coefficients in a balanced equation represent the ratio of molecules but not the ratio of moles.

Stoichiometry is only applicable to reactions that go to completion with no reactants remaining.

The mole ratio is derived from the subscripts in a chemical formula.

When solving stoichiometry problems, it is essential to convert all given quantities into moles before applying the mole ratio.

When determining the limiting reactant, the reactant with the smallest mass is always the limiting reactant.

The theoretical yield is the maximum amount of product that can be produced in a chemical reaction under ideal conditions.

The actual yield of a reaction can be greater than the theoretical yield if the reaction is performed carefully.

Percentage yield is calculated by dividing the theoretical yield by the actual yield and multiplying by 100%.

In reactions with multiple reactants, adding more of the excess reactant will increase the theoretical yield of the product.

The limiting reactant is the substance that has the higher molar mass.

Stoichiometry is used in the design of airbags to ensure they inflate enough regardless of the outside temperature.

The oxidizers, such as ferric oxide (Fe_2O_3), in airbags react with nitrogen gas to produce energy.

A mixture of gasoline and oxygen must always be in a 1:12.5 ratio to ensure complete combustion.

Catalytic converters increase the amount of pollutants released into the air.

The efficiency of a reaction, measured by its percentage yield can be affected by side reactions.

In a chemical reaction, the limiting reactant is the reactant that is present in the largest quantity.

If the actual yield of a reaction is equal to the theoretical yield, the percentage yield is 0%.

Avogadro's number is needed to convert from grams to moles.

In the reaction $N_2 + 3H_2 \rightarrow 2NH_3$, if you have 1 mole of $N_2$ and 4 moles of $H_2$, then $N_2$ is the limiting reactant.

Stoichiometric calculations can be used to predict the mass of reactants needed to produce a certain volume of gas at STP.

In airbag design, sodium chloride (NaCl) is the primary gas generant, producing nitrogen gas upon decomposition.

The coefficients in a balanced chemical equation can always be used directly as a volume ratio for gases, regardless of temperature or pressure.

If 50.0 g of a reactant is used and the theoretical yield of a product is calculated to be 75.0 g, the actual yield must be lower than 50.0 g.

Even if a reaction has a high percentage yield, it is still essential to consider the environmental impact of any by-products formed.

Because air is approximately 78% nitrogen, car engines use pure nitrogen gas to achieve more efficient fuel combustion.

In the reaction (A + B \rightarrow C), if the molar mass of A is greater than B, then A will always be the limiting reactant if equal masses of A and B are used.

In a balanced chemical equation, the sum of the coefficients on the reactant side must equal the sum of the coefficients on the product side.

If a solid product is not completely dry when its mass is measured, the calculated percentage yield will be lower than the true value.

According to the U.S. Clean Air Act, the same standards for air pollutants in car exhausts are applied to both cars and motorcycles.

A catalyst in a catalytic converter is consumed during the reaction to form stable intermediates.

To increase the actual yield of a chemical reaction it is always best to increase the temperature above the normal operating conditions.

The percentage yield of two reactions forming water, one producing it from hydrogen and oxygen, and the other from acid-base neutralization, must be the same.

Manufacturers often use the most expensive reactant as the excess reactant to ensure the cheaper reactant is fully consumed.

Removing the products of a reaction as they're formed won't change the theoretical yield.

Mass spectrometry only functions if the entire amount of product created can be measured.