# Concentration & Volume Calculations Involving Equations

This is part of Year 11 HSC Chemistry course under the topic of Molarity.

### HSC Chemistry Syllabus

• relate stoichiometry to the law of conservation of mass in chemical reactions by investigating:

– balancing chemical equations (ACSCH039)

– solving problems regarding mass changes in chemical reactions (ACSCH046)

• Manipulate variables and solve problems to calculate concentration, mass or volume using:
– c = \frac{n}{V} (molarity formula (ACSCH063))

### Example 1

The reaction between nitric acid and potassium produces potassium nitrate and hydrogen gas.

What volume of a 0.250 mol L–1 solution of nitric acid is required to completely react with 15.0 g of potassium?

### Example 2

43.50 mL of a 0.100 mol L–1 solution of sodium hydroxide is required to completely react with a 25.00 mL hydrochloric acid solution.

Calculate the concentration of the hydrochloric acid solution.

### Example 3

Excess calcium carbonate is added to a 500.0 mL solution of hydrochloric acid to produce calcium chloride, carbon dioxide and water.

If 2.20 mol carbon dioxide is produced, what was the concentration of the hydrochloric acid solution?