Activity 3.12:
Aim: To determine the empirical formula of magnesium oxide.
Materials: 10 cm magnesium ribbon and sand paper
Apparatus: Crucible with lid, tongs, Bunsen burner, tripod stand, pipeclay triangle and electronic balance
Procedure:
1. Weigh and record the mass of a crucible together with its lid.
2. Rub 10 cm magnesium ribbon with a sand paper until shiny. Coil the magnesium ribbon and put it in the crucible.
3. Weigh and record the mass of the crucible together with its lid and the coil of magnesium ribbon.
4. Set up the apparatus as shown in Figure 3.12.
5. First, heat the crucible without its lid.
6. When magnesium ribbon starts to burn, close the crucible with its lid.
7. Using a pair of tongs, lift the lid slightly from time to time and quickly place it back.
8. When the burning of magnesium ribbon is complete, take off the lid and heat the crucible with high temperature for 1 to 2 minutes.
9. Put back the lid of the crucible and allow it to cool to room temperature.
10. Weigh the mass of crucible together with its lid and its contents again.
11. Repeat the heating, cooling and weighing process until a constant mass is obtained.
12. Record the constant mass in Table 3.4.
Results:
Interpreting data:
1. Based on your results, determine the masses of magnesium and oxygen that combine.
2. Determine the empirical formula of magnesium oxide.
Discussion:
1. What is the purpose of rubbing the magnesium ribbon with a sand paper before using it?
2. Name the white fumes that are produced.
3. Why are steps 6, 7 and 11 performed?
4. What will happen if the white fumes are released into the environment?
Answer:
Discussion
1. To remove the oxide layer on the surface of the magnesium tape
2. Magnesium oxide
3. – Step 6 aims to prevent the loss of white fumes– Step 7 aims to allow air to enter the crucible so that oxygen in air can react with magnesium tape
– Step 11 aims to ensure that the magnesium is completely burned
4. The results obtained is not accurate and could affect the determination of the empirical formula.
Aim: To determine the empirical formula of magnesium oxide.
Materials: 10 cm magnesium ribbon and sand paper
Apparatus: Crucible with lid, tongs, Bunsen burner, tripod stand, pipeclay triangle and electronic balance
Procedure:
1. Weigh and record the mass of a crucible together with its lid.
2. Rub 10 cm magnesium ribbon with a sand paper until shiny. Coil the magnesium ribbon and put it in the crucible.
3. Weigh and record the mass of the crucible together with its lid and the coil of magnesium ribbon.
4. Set up the apparatus as shown in Figure 3.12.
5. First, heat the crucible without its lid.
6. When magnesium ribbon starts to burn, close the crucible with its lid.
7. Using a pair of tongs, lift the lid slightly from time to time and quickly place it back.
8. When the burning of magnesium ribbon is complete, take off the lid and heat the crucible with high temperature for 1 to 2 minutes.
9. Put back the lid of the crucible and allow it to cool to room temperature.
10. Weigh the mass of crucible together with its lid and its contents again.
11. Repeat the heating, cooling and weighing process until a constant mass is obtained.
12. Record the constant mass in Table 3.4.
Results:
Interpreting data:
1. Based on your results, determine the masses of magnesium and oxygen that combine.
2. Determine the empirical formula of magnesium oxide.
Discussion:
1. What is the purpose of rubbing the magnesium ribbon with a sand paper before using it?
2. Name the white fumes that are produced.
3. Why are steps 6, 7 and 11 performed?
4. What will happen if the white fumes are released into the environment?
Answer:
Discussion
1. To remove the oxide layer on the surface of the magnesium tape
2. Magnesium oxide
3. – Step 6 aims to prevent the loss of white fumes– Step 7 aims to allow air to enter the crucible so that oxygen in air can react with magnesium tape
– Step 11 aims to ensure that the magnesium is completely burned
4. The results obtained is not accurate and could affect the determination of the empirical formula.