Unit 4 - Metals

Question 1

alloy

Answer 1

a mixture of a metal with at least one other element

Question 2

types of alloy

Answer 2

steel = iron + carbon
brass = copper + zinc
bronze = copper + tin
solder = tin + lead

Question 3

why do alloys exist

Answer 3

for a better appearance
to resist corrosion
to make metal stronger

Question 4

why are alloys harder than pure metals

Answer 4

pure metal : disorderly arrangement due to same size atoms - causes layers and atoms to slip easily
alloys : disorderly arrangement = structure is distorted = slip doesn’t occur easily

Question 5

extraction of metals : raw materials need to extract iron

Answer 5

1) limestone
2) coke (carbon)
3) hematite (carbon oxide)
4) air

Question 6

hot waste gases

Answer 6

• carbon monoxide (poisonous)
• carbon dioxide (acidic rain)
• sulphur dioxide (greenhouse gases)

Question 7

labels of blast furnance

Answer 7

(refer to book)

Question 8

stage 1 of extraction of metals

Answer 8

carbon reacts with oxygen to form CO2 - equation: C + O2 ——> CO2
limestone break down to produce carbon dioxide/quicklime - equation: CaCO3 ——> CaO + CO2