Ilab Chemistry Lab

Maria Reyes iLab, Week #3

ATOMIC WEIGHT OF MAGNESIUM LAB

Introduction

The purpose of this lab was to determine the atomic weight of magnesium by measuring the amount of hydrogen gas evolved when hydrochloric acid reacted with magnesium. In order to measure the atomic weight I needed to measure the amount of the hydrogen gas that was evolved in reaction to the acid of the magnesium. The reaction used was: Mg + 2HCl --> H2 + Mg2+ (aq) + 2Cl- (aq). The major findings of this experiment were that there was a chemical reaction between hydrochloric acid and magnesium, and the reaction produced the hydrogen gas. The results also indicated how many moles of hydrogen gas were equal to the amount of moles of magnesium consumed.

Procedure

Step 1:
When the bubbles stopped and the shaded area disappeared, it indicated that the magnesium had been consumed.

Discussion In order to measure the atomic weight of magnesium after it is consumed, it has to be mixed with hydrochloric acid. Once it has consumed it will produce hydrogen gas, which will be trapped and measured. This means that the atomic weight of magnesium will result from separating the hydrogen gas from the acid in the magnesium. The chemical equation mentioned in the introduction indicates that one mole of hydrogen gas is produced for every mole of magnesium that reacts. In this lab, there is a 1:1 ratio between the number of moles of hydrogen gas evolved and the number of moles of magnesium consumed in the reaction. Therefore, the number of moles of hydrogen gas evolved is equal to the number of moles of magnesium consumed. The atomic weight of magnesium is equal to the weight of magnesium consumed per moles of hydrogen gas evolved.