SAT Subject Test Chemistry

PART 2

REVIEW OF MAJOR TOPICS

CHAPTER 6

Stoichiometry (Chemical Calculations) and the Mole Concept

VOLUME–VOLUME PROBLEMS

This type of problem involves only volume units and therefore can make use of Gay-Lussac’s Law: “When gases combine, they combine in simple whole-number ratios.” These simple numbers are the coefficients of the equation.

A typical problem concerning just volume relationships is as follows:

TIP 

Know Gay-Lussac’s Law.

EXAMPLE 1:

What volume of NHis produced when 22.4 liters of nitrogen are made to combine with a sufficient quantity of hydrogen under the appropriate conditions?

USING THE PROPORTION METHOD:

USING THE FACTOR-LABEL METHOD:

From the 2nd step on you would proceed as follows:

USING THE MOLE METHOD:

To solve this problem you would proceed as follows:

EXAMPLE 2: What volume of SOwill result from the complete burning of

pure sulfur in 8 liters of oxygen until all the oxygen is used?

USING THE PROPORTION METHOD:

USING THE FACTOR-LABEL METHOD:

USING THE MOLE METHOD (NOT REALLY PRACTICAL IN THIS CASE):

TRY THESE VOLUME-VOLUME PRACTICE PROBLEMS:

5. How many liters of hydrogen are necessary to react with sufficient chlorine to produce 12 liters of hydrogen chloride gas?

Ans. 6 L H2*

6. How many liters of oxygen will be needed to burn 100 liters of carbon monoxide?

Ans. 50 L O2*