C5 How Much?

Question 0

What is the PH of a weak acid

Answer 0

4–6

Question 1

What is the PH of a strong acid

Answer 1

1–2

Question 2

What does the strength of an acid tell you?

Answer 2

Tells you what proportion of acid molecules ionise in water

Question 3

How do you make an insoluble salt?

Answer 3

To make an insoluble salt you need ions which are in a solutions so that they can move about

Question 4

What is the equation to work out number of moles?

Answer 4

Mr

Question 5

What is a mole?

Answer 5

The relative atomic mass of an element is the average mass of an atom compare to the mass of an atom of carbon 12

Question 6

Uses of a gas syringe in measuring gas volumes

Answer 6

1) might blow plunger off
2) Collects most gases
3) to the nearest centimetre cubed

Question 7

Uses of an upturned measuring cylinder in gas volumes

Answer 7

1) Bubbles gas

2) no good for hydrogen/chloride/ammonia as they dissolve in water

Question 8

What is electrolysis

Answer 8

The breaking down of a substance with electricity

Question 9

What is the equation at the anode?

Answer 9

4OH- - 4e- >O2 + 2H2O

Question 10

What is the equation at the Cathode?

Answer 10

2H+ + 2e- > H2

Question 11

How can you increase the amount of substance produced at electrolysis?

Answer 11

If you increase the amount of electrons, you increase the amount of substance produced

Question 12

How too calculate empirical formula ?

Answer 12

1) List all elements
2) Write there in experimental masses/percentage
3) divide each mass/percentage by the Ar
4) Turn numbers into a ratio
5) get the ratio into simplest form

Question 13

What does it mean if mass is conserved in a chemical reaction

Answer 13

This means that the mass of reactants is equal to mass of products

Question 14

What is empirical formula

Answer 14

Empirical formulas give the smallest whole number ratio of atoms in a compound

Question 15

1 dm cubed

Answer 15

Is 1000 cm³ (litre)

Question 16

Name the two calculations to work out concentration

Answer 16

concentration X volume

Number of moles X Mr

Question 17

How do you make solution more concentrated

Answer 17

The more solute you dissolve in a given volume, The more crowded the molecules are and the more concentrated solution

Question 18

What is a precipitation reaction?

Answer 18

To solutions reacting together to make an insoluble substance
This makes the solution turn cloudy/murky

Question 19

What does equilibrium do?

Answer 19

It will move in the opposite way to balance the chemical reaction

Question 20

What is the contact process used for?

Answer 20

To make sulphuric acid

Question 21

How do you make sulphuric acid in the contact process?

Answer 21

First burn sulphur in air (S + O2 > SO2)

Then oxidise to 2SO2 (2SO2 + O2 <> 2SO3

Add water to sulphur trioxide to make sulphuric acid ( SO3 + H2O > H2SO4)

Question 22

What is the equation for neutralisation?

Answer 22

Acid + alkali = salt + water