Topic 5 - Compounds

Question 1

Define compound

Answer 1

A substance containing two or more different types of atoms that are chemically bonded together

Question 2

What is the equation for the thermal decomposition of CaCO3

Answer 2

CaCO3 ->* CaO + CO2

• heat to be written above arrow

Question 3

Describe the test for CO2

Answer 3

Bubble through limewater, turns cloudy

Question 4

Explain the uses of CO2?

Answer 4

• fire extinguishers (because CO2 is more dense than air)

* carbonated drinks (because CO2 is soluble in water, forming carbonic acid)

Question 5

What is the problem with CO2?

Answer 5

It is a greenhouse gas, meaning that it prevents infrared radiation from escaping the earth, heating up the atmosphere and causing global warming

Question 6

Describe the decomposition of copper(II) carbonate

Answer 6

CuCO3(s) -> CuO(s) + CO2(g)

• copper carbonate is a green powder
• copper oxide is black powder

Heat the copper(II) oxide in a horizontal test tube with a bung with a hole in the centre of it filled by a delivery tube into an empty test tube. Because CO2, it collects at the bottom, and can be collected and tested