Nat 4 Chemistry Assessment

Question 1

What is the formula for metals reacting with oxygen

Answer 1

metal + oxygen -> metal oxide
eg. magnesium + oxygen -> magnesium oxide

Question 2

Metals reacting with oxygen can make physical reactions like?

Answer 2

slight glow, bright glow, bright flame

Question 3

What is the formula for metals reacting with acid?

Answer 3

metal + acid -> salt + hydrogen

Question 4

Sulfuric acid becomes?

Answer 4

Sulfate

Question 5

Hydrochloric acid becomes?

Answer 5

Chloride

Question 6

Nitric acid becomes?

Answer 6

Nitrate

Question 7

What is the formulae of metals reacting with water?

Answer 7

metal + water -> metal hydroxide + hydrogen

Question 8

metals are found in the earths crust in?

Answer 8

rocks

Question 9

what is an ore?

Answer 9

a rock that contains a naturally occuring metal compound

Question 10

what metals are found uncombined?

Answer 10

silver and gold

Question 11

Most reactive metals in order

Answer 11

potassium, sodium, lithium, calcium, magnesium, aluminium

Question 12

Middle reactive metal

Answer 12

carbon

Question 13

Least reactive in order

Answer 13

zinc, iron, copper, silver and gold

Question 14

what method do you use to extract potassium, sodium, lithium, calcium, magnesium and aluminium?

Answer 14

Extracted by electrolysis of molten compounds

Question 15

what method do you use to extract zinc, iron and copper

Answer 15

Extracted by reduction, by heating with carbon

Question 16

what do you use to extract silver and gold?

Answer 16

nothing as they are found as pure elements in nature

Question 17

when a metal is exposed to the environment it will react and change into its?

Answer 17

ions

Question 18

What is corrosion?

Answer 18

corrosion is a chemical reaction where the surface of a metal changes into a compound

Question 19

what is rusting?

Answer 19

rusting is the special name to the corrosion of iron

Question 20

what causes corrosion?

Answer 20

different metals will corrode at different rates due to their reactivity

Question 21

in order for corrosion to occur what must be present?

Answer 21

water and oxygen

Question 22

how do you detect rust?

Answer 22

Using ferroxyl indicator rust will be present when it changes from yellow to blue.

Question 23

2 ways to prevent rust?

Answer 23

physical barrier and sacrificial protection

Question 24

what types of physical barriers would you use?

Answer 24

paint, oils and grease or coating steel with a second protective metal

Question 25

what is sacrificial protection?

Answer 25

connecting a metal above iron in the electrochemical series which will slow down the corrosion of iron.

Question 26

chemical energy ->

Answer 26

electrical energy

Question 27

a simple battery is called a?

Answer 27

cell

Question 28

how can a cell be made?

Answer 28

by joining two different metals

Question 29

an electrical current will flow from the?

Answer 29

most reactive to the least reactive