Skip to content
MathsGenie logo
Open app

Course home

  1. IGCSE
  3. Chemistry Edexcel
  5. Question bank

Chemical formulae, equations and calculations

EasyMedium
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677
Question 22

When copper powder is heated in a crucible, it reacts with oxygen in the air to form copper(II) oxide, CuO\text{CuO}CuO.

A class of students investigated the relationship between the mass of copper heated and the mass of copper(II) oxide formed.

Each student was given a different mass of clean copper powder to heat. The students used the following method:

  • Weigh a crucible and its lid.
  • Place the copper powder in the crucible, replace the lid, and reweigh.
  • Heat the crucible strongly, lifting the lid from time to time.
  • Allow the crucible and lid to cool and reweigh.
  • Repeat the heating, cooling, and reweighing until two consecutive masses are the same.
  • Calculate the mass of copper(II) oxide formed.
a.

Why is it necessary to lift the lid from time to time while heating?

[1]
b.

Why is it necessary to repeat the heating until two consecutive masses are the same?

[1]
c.

Show how the mass of copper(II) oxide formed can be calculated from the readings obtained.

[1]
d.

The results of each student's experiment are given in the table below:

Mass of copper (g)Mass of copper(II) oxide (g)
0.400.50
0.801.00
1.201.85
1.602.00
2.002.50
2.403.00

Identify the anomalous result by stating the mass of copper for which it occurred.

[1]
e.

Use the consistent results from the table to calculate the mass of copper(II) oxide formed when 1.44 g of copper is completely reacted.

[2]

Chemical formulae, equations and calculations Questions

  1. IGCSE
  2. /Chemistry
  3. /Chemical formulae, equations and calculations