PPE Revision

Question 1

What is the mass number?

Answer 1

The number of protons plus neutrons.

Question 2

Why doesn’t an atom have any charge?

Answer 2

They have the same number of positively charged protons in the nucleus, as the number of negatively charged electrons in their shells.

Question 3

The periodic table groups?

Answer 3

They have the same number of elections in their outer shell and have similar chemical properties.

Question 4

What is the correct box to tick?

Answer 4

S (Sulphur)

Question 5

Particles that include non-metals and metal:

Answer 5

Ions

Question 6

Particles that include two non-metals:

Answer 6

Molecules

Question 7

What is the process of limestone?

Answer 7

Limestone is calcium carbonate. Calcium oxide is produced through thermal decomposition. Calcium hydroxide is created by adding water. Limestone can be used to neutralise acids by using alkali.

Question 8

How could the accuracy be improved?

Answer 8

By repeating the steps at least 3 times and calculating the average and decrease the intervals between results being taken.

Question 9

How are fractions of oil separated?

Answer 9

The crude oil enters the fractionating column which heats up to around 350 degrees. The hyrdrocarbons in the crude oil has different boiling points. The weaker hydrocarbons (less bonds) have a lower boiling point, but the larger hydrocarbons has a higher boiling point.

Question 10

Suspension of limestone?

Answer 10

Sulphur dioxide and nitrogen dioxide are slightly acidic, they therefore react with Calcium Carbonate to produce a salt, water and carbon dioxide. This reduces the amount of sulcus dioxide and nitrogen oxide in the air, so it reduces levels of acid rain.

Question 11

What is the answer for the hyrdrocarbon?

Answer 11

C2H4

Question 12

Why isn’t his prediction about the trend correct?

Answer 12

Because after 400 grams, the force needed begins to decrease as for 700 grams, the force needed is 100 newtons.

Question 13

Why are there so many theories?

Answer 13

Lack of reliable evidence from the time, and some evidence can cause conflict causing a number of theories.

Question 14

How do smart polymers differ from normal polymers?

Answer 14

They change their properties when there are changes in the environment e.g. They react to heat and temperature.

Question 15

Why are vegetable oils useful for both fuels and in food?

Answer 15

They contain a lot of energy.

Question 16

Why are vegetable oils more useful compared to water in cooking?

Answer 16

They have a high boiling point, so it provides a lot of energy.

Question 17

State two processes used in extracting vegetable oil from seeds.

Answer 17

Plant material is crushed and the oil is removed by pressing or distillation, water and other impurities are removed.

Question 18

How do emulsifiers work?

Answer 18

The head is hydrophilic and the tail is hydrophobic. The “tail” dissolves in the oil to create tiny droplets. The surface of each oil droplet is chafed by the heads sticking out into the water. As the head is negatively charged, the like charges repel each other. This keeps them spread throughout the water, stopping the oil and water separating into two layers.

Question 19

What is atomic number?

Answer 19

The number of protons.