STOICHIOMETRY OF A CHEMICAL REACTION

INTRODUCTION: All chemical reactions proceed on the basis of the molar ratios that are found in the balanced equations of the reaction. For example in the synthesis of water from its elements—

2 H₂ + O₂ à 2 H₂O

two moles of hydrogen must react with one mole of oxygen gas to produce two moles of water.

In the reaction we will investigate we will use magenesium metal (Mg) and hydrocholoric acid (HCl). The magnesium will be the limiting reactant and hydrochloric acid will be used in excess.

MATERIALS:

gas collecting tube magnesium HCl beakers

rubber stoppers calculator periodic table goggles/aprons

PROCEDURE:

1. Your instructor will provide you with 2 strips of Mg metal.

2. Measure the length of the Mg and use the ratio provided to determine the mass of the Mg.

3. Your instructor will place the HCl into the gas collecting tube for you.

4. Follow the instructions to allow the chemical reaction to run to completion.

5. Collect the data on volume of hydrogen gas produce.

6. Repeat with the second sample of Mg.

7. All of your data should be placed into a DATA TABLE !

ANALYSIS:

1. Calculate the moles of each sample of Mg used in the experimental trials.

2. Calculate the moles of hydrogen gas produced for each trial.

Note: 1 mole= 22.4 L and 1000 mL = 1 L

3. Write the balanced equation for the reaction of Mg and HCl.

Use appropriate subscripts e.g. (s) for solid etc.

4. Using your data determine if the mole ratios for the experiment match the mole ratios in the balance equation.

CONCLUSION:

Write your own conclusion based on the experiment.