Chemisty Project

The aim of this investigation is to find the molar mass of magnesium by making magnesium and hydrochloric acid react and then apply the ideal gas equation.

The independent variable of this experiment is the amount used of each substance. However, these were not not be varied. The dependent variable is the amount of hydrogen gas which is formed. The controlled variables are the pressure and temperature in the room, and the width (and thereby weight) of the magnesium ribbon.

Materials used:

Magnesium (Mg) ribbon

Hydrochloric acid (HCl), 35% concentrated

Copper (Cu) wire

Eudiometer

Thermometer

Barometer

Measuring cylinder (2000 cm3)

Method:

50 mm of the Mg ribbon was weighed.

10 cm3 of HCl was poured into the eudiometer.

The rest of the eudiometer was filled with water.

The Mg ribbon was wrapped around the Cu wire and hung in the eudiometer cork.

The measuring cylinder was filled with water.

The eudiometer was put upside-down in the measuring cylinder.

After the reaction between HCl and Mg was complete, the eudiometer was allowed to cool down to reach room temperature.

The eudiometer was arranged so that the gas inside had the same pressure as the air pressure outside the room.

The molar mass of magnesium was calculated using

In order to ensure that the investigation resulted in valid results, the experiment was conducted four times.

These were the measured values:

Table 1: Controlled Variables

Variable Value

Pressure of the room 100.3 * 103 Pa

Temperature of the room 292.65 K