Alloys

Question 1

Brass

Answer 1

70% copper, 30% zinc.
Harder than pure copper.

Question 2

Bronze

Answer 2

90% copper, 10% tin.
Harder than pure copper.

Question 3

Mild steel

Answer 3

99.7% iron, 0.3% carbon.
Stronger and harder than pure iron.

Question 4

Stainless steel

Answer 4

74% iron, 18% chromium, 8% nickel.
Increased resistance to corrosion, used to make cutlery.