Questions Corrections 2020

Question 1

Explain how these observations (of pale grey crystals forming and the solution turning blue) shows that silver is less reactive than copper

Answer 1

The crystals are silver
The copper ions produced are blue
Because copper displaces silver

Question 2

A student is given three metals X Y Z, metals are magnesium, iron and copper
Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid

Answer 2

Add the metals to HCL
Measure temperature change
Copper will have no reaction shown by no temperature change
For magnesium and iron the magnesium increases in temperature more than iron
Keep the same volume of HCL and same mass of metal

Question 3

Give two reasons why reactions with a high atom economy are used in industry

Answer 3

For sustainable development
To produce higher percentage of useful product

Question 4

4 differences of nuclear model of the atom and the plum pudding model

Answer 4

Mostly empty space
Positive charge is all in the nucleus
Mass is concentrated in nucleus
Plum pudding model did not have a nucleus

Question 5

Explain the trend in boiling points of the halogens

Answer 5

Boiling point increases
As the relative formula mass increases
So intermolecular forces increase
So more energy is needed to overcome the intermolecular forces