6 marksFoundation and Higher
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]6 marksFoundation and Higher
Silicon dioxide (silica) melts at 1710 °C. Poly(ethene) softens at about 120 °C. Methane boils at −162 °C.
Explain the differences in these temperatures.
Refer to the structure and bonding of each substance.
[6 marks]4 marksFoundation and Higher
A student heats 2.40 g of magnesium ribbon in an open crucible. It all reacts to form 4.00 g of magnesium oxide.
2Mg+O2→2MgO.1Calculate the mass of oxygen that reacted with the magnesium.
[1 mark] .2The student says: "The mass went up, so mass was not conserved."
Explain why the student is wrong.
[2 marks] .3The student repeats the experiment in a sealed container full of air and weighs the whole container. Predict what happens to the total mass.
[1 mark] 6 marksFoundation and Higher
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]4 marksFoundation and Higher
The table shows the boiling points of some noble gases.
.1Estimate the boiling point of krypton.
[1 mark] .2Describe the trend in boiling point down the group.
[1 mark] .3Explain why the noble gases are unreactive.
[2 marks]