Chemistry

Question 1

Chemistry

Identify a gas that makes up about 78% of the atmosphere.

Answer 1

Nitrogen

Question 2

Chemistry

Identify a gas that makes up about 0.9% of the atmosphere.

Answer 2

Argon

Question 3

Chemistry

Identify a gas produced by the thermal decomposition of calcium carbonate.

Answer 3

Carbon Dioxide

Question 4

Chemistry

Explain how a catalyst increases the rate of a reaction.

Answer 4

Provides an alternate pathway with a lower activation energy.

Question 5

Chemistry

Explain why diamond has a high melting point.

Answer 5

Giant covalent structure.

Lots of strong covalent bonds which require a lot of energy to break.

Question 6

Chemistry

Explain the melting point of Buckminster fullerene.

Answer 6

Simple molecular structure.
Low melting point compared to giant covalent structures, weak intermolecular forces.
High melting point compared to other simple molecular substances, larger mass.

Question 7

Chemistry

Describe a test that can be used to distinguish between an alkane and an alkene.

Answer 7

React with bromine water,
NOT under UV light.
Alkane will stay orange.
Alkene will turn orange to colourless.