Chemical Changes-Paper 1

Question 1

What are titrations used for?

Answer 1

Calculating concentrations

Question 2

Name safety precautions for titrations

Answer 2

Pour acid BELOW EYE LEVEL

and wear safety goggles

Question 3

How do you increase the accuracy of your titration?

Answer 3

You must have several consistent readings, firstly doing a rough one to get an idea where the solution changes colour.

Question 4

acid + base —-> ???

Answer 4

Acid + Base ——> Salt + water

oxides and hydroxides are bases

Question 5

Why shouldn’t you use universal indicator in titration calculations?

Answer 5

As it gives an estimate pH, not an accurate one.

Instead use litmus, methyl orange or phenolphthalein.

Question 6

What colours does litmus go?

Answer 6

Acid= red

Alkali=Blue

Question 7

What colours does phenolphthalein go?

Answer 7

Acid=colourless

Alkaline= pink

Question 8

What colours does methyl orange go?

Answer 8

Acid= red
Alkaline= Yellow

Question 9

metal + acid —–> ??????

Answer 9

salt + hydrogen

Question 10

metal + water —–> ???????

Answer 10

metal + water —–> metal hydroxide + hydrogen

Question 11

In a displacement reaction what happens to the metal ion?

Answer 11

Reduced

Question 12

In a displacement reaction what happens to the metal atom

Answer 12

oxidised

Question 13

Why can’t ionic solids be electrolysed?

Answer 13

As the ions are in fixed positions so can’t move.

Question 14

EQUATION FOR VOLUME OF GAS

Answer 14

MASS OF GAS/ Mr of gas X24