Exam questions

Question 1

Compare the structure and properties of methane and hexane

Answer 1

• Both are hydrocarbons
• Both contain C-H bonds
• Hexane has a higher melting and boiling point
• Hexane is less flammable
• Both are flammable
• Hexane is more viscous
• Neither conduct electricty

Question 2

Suggest how copper sulfate can be used to test for the presence of water

Answer 2

Add water to anhyrdous copper and the colour should change from white to blue if water is present

Question 3

Explain how distillation is used to obtain potable water from salty water

Answer 3

Heat salty water
So water evaporates
Cool the water vapor
Which condenses to form potable water

Question 4

Why is obtaining potable water from salty water more expensive than obtaining potable water from ground water?

Answer 4

Distillation requires energy to boil salty water
But groundwater only needs filtering and sterilising

Question 5

How is phytomining used to extract copper

Answer 5

Plants absorb metal compounds
Plants are harvested
Plants are burned
Copper compounds from ash are dissolved in acid
Solution of the copper compound is electrolysed

Question 6

Describe how nitrogen dioxide is produced in the engine of a car that burns?

Answer 6

At high temperatures in the engine
Nitrogen reacts with oxygen to produce nitrogen dioxide

Question 7

Explain how a catalyst can increase the rate of reaction

Answer 7

Provides an alternative pathway
Which has a lower activation energy

Question 8

How is equilbrium reached

Answer 8

When the apparatus prevents the escape of reactants and products
And the forward and reverse reactions occur at the same rate