Exam Questions

Question 1

When chlorine is bubbled into potassium bromine solution, the solution turns orange. Explain why this happens

Answer 1

Bromine is orange at room temp

Because of displacement the solution turns orange

Question 2

Barium sulfate can be prepared as a white precipitate
Describe how you could prepare a pure, dry sample of barium sulfate from barium chloride solution and sodium sulfate solution

Answer 2

Mix the solutions to form a precipitate of barium sulfate
Filter
Wash the precipitate in distilled water
Dry on filter paper

Question 3

Explain why the catalyst is spread onto the honeycomb structure rather than large pieces in a catalytic converter

Answer 3

Got a larger surface area
More collisions
Happens quickly

Question 4

Explain what is meant by theoretical yield

Answer 4

The amount of product calculated
Using the equation for reaction
Theoretical yield = actual yield divided by percentage yield

Question 5

Hydrogen peroxide reacts with some iron compounds. The molecular formula of hydrogen peroxide is H2O2 give the empirical formula of hydrogen peroxide

Answer 5

HO

Question 6

Give the meaning of a covalent bond

Answer 6

Shared pair of electrons

Question 7

Give a use of graphite that depends on its ability to conduct electricity

Answer 7

HT leads

Question 8

A test tube filled with hydrogen chloride gas. The test tube was inverted in water and left.
The liquid level rose up to the top of the test tube. Explain what is formed in the test tube after the water had entered.

Answer 8

Hydrochloride acid

The hydrogen chloride dissolves in water