A student wants to make pure, dry crystals of copper sulfate from copper oxide (an insoluble black powder) and dilute sulfuric acid.
Plan a method the student could use.
In your answer, explain the reason for each step.
[6 marks]OCR Gateway GCSE Chemistry November 2020 Paper 1
5 questions on this paper's topics
28:001 of 5
Sodium chloride melts at 801 °C. It does not conduct electricity when solid, but it does when molten.
.1
Explain why sodium chloride has a high melting point.
[2 marks].2
Explain why molten sodium chloride conducts electricity but solid sodium chloride does not.
[2 marks]A student investigates what is produced when aqueous solutions of copper chloride and sodium chloride are electrolysed using inert electrodes.
Plan an investigation to find the products at each electrode for both solutions.
Include how you would identify any gases.
[6 marks]The table shows the boiling points of some noble gases.
| Noble gas | Boiling point in °C |
|---|---|
| Helium | −269 |
| Neon | −246 |
| Argon | −186 |
| Krypton | ? |
| Xenon | −108 |
.1
Estimate the boiling point of krypton.
[1 mark].2
Describe the trend in boiling point down the group.
[1 mark].3
Explain why the noble gases are unreactive.
[2 marks]Some substances are listed below.
Copper, carbon dioxide, air, sodium chloride.
.1
Which substance is an element?
[1 mark].2
Which substance is a mixture?
[1 mark].3
Give the number of different elements in the formula .
[1 mark].4
A student has a mixture of sand and water. Choose the best method to get the sand.
[1 mark]