Calculating and explaining energy changes

Question 1

What does the reaction of hydrogen and oxygen make?

Answer 1

They react and give out energy,

They produce water which isn’t a pollutant

Question 2

Pros and Cons for using hydrogen gas to power vehicles

Answer 2

Pros:
Produces water, so it’s very clean.

Cons:
Difficult to store
Engines would have to to be adapted

Question 3

What is a fuel cell

Answer 3

A fuel cell is an electrical cell that’s supplied with a fuel and oxygen and uses energy from the reaction between them to generate electricity

Question 4

What are the flame tests for metal ions?

Answer 4

The colour tests

Question 5

What flame does lithium give?

Answer 5

Crimson

Question 6

What flame does sodium give?

Answer 6

Yellow

Sodium sun yellow

Question 7

What metal ion gives off a lilac flame?

Answer 7

Potassium

Question 8

What colour flame does calcium give?

Answer 8

Red

Question 9

What metal ion gives a green flame?

Answer 9

Barium

Question 10

Name another test for metal ions

Answer 10

Some metal ions form a coloured precipitate with NaOH

Sodium hydroxide

Question 11

Why do some metal ions form coloured precipitates with sodium hydroxide

Answer 11

Many metal hydroxides are insoluble and precipitate out of solution when formed

Question 12

What three metal ions form a white precipitate with sodium hydroxide?

Answer 12

Calcium
Magnesium

Aluminium - what at first but then dissolves in excess to form a colourless solution

Question 13

What colour precipitate forms when copper (II) reacts with sodium hydroxide

Answer 13

Blue

Question 14

A green precipitate is formed when sodium hydroxide is added to the metal ion, what is it?

Answer 14

Iron (II)

Question 15

A blue precipitate is formed when a metal ion reacts with sodium hydroxide, what is it?

Answer 15

Iron (III)

Question 16

How do you test for carbon dioxide?

Answer 16

It turns limewater cloudy

Question 17

How can you test for carbonate ions?

Answer 17

Carbonates react with dilute acid to form carbon dioxide, you test for carbon dioxide with lime water

Question 18

How do you test for chloride bromide and iodide?

Answer 18

Add dilute nitric acid followed by silver nitrate solution

Question 19

What colour precipitate does chloride give of silver chloride?

Answer 19

White

Question 20

What colour precipitate does bromide give of silver bromide

Answer 20

Cream

Question 21

What colour does iodide give of silver iodide?

Answer 21

Yellow

Question 22

What are the three coloured precipitates formed with hallide ions?

Answer 22

Chloride = white

Bromide = cream

Iodide = yellow

Remember as the alphabet increases the colour intensity increases

Question 23

How can you text for sulfate ions?

Answer 23

Add dilute hydrochloric acid followed by barium chloride solution.
A white precipitate of barium sulfate means the original compound was a sulfate.