Metals

Question 1

How does alloying make the metal harder and stronger?

Answer 1

The atoms of the added elements are of a different size. These added atoms disrupts the regular arrangement of the metal atoms, preventing the layers of metal atoms from sliding over each other easily when a force is applied.

Question 2

What are the reactions of various metals with Cold Water (CW) and Steam (S)?

Answer 2

K- Reacts VERY VIOLENTLY with CW; hydrogen burns in air with a lilac flame.
Na- Reacts VIOLENTLY with CW, hydrogen burns in air.
Ca- Reacts READILY with CW
Mg- reacts VERY SLOWLY with CW, HOT Mg reacts VIOLENTLY with steam.
Zn- NO OBSERVABLE REACTION with CW, hot Zn reacts readily with steam.
Fe- NO OBSERVABLE REACTIONS with CW, RED-HOT iron reacts SLOWLY with steam.

Question 3

What metal and below on the RS can be reduced by H and C respectively?

Answer 3

H– Lead and below

C– Zn and below

Question 4

What are the advantages for recycling metals?

Answer 4

1. Conserve natural resources: saves limited amt of non-renewable metal ores
2. Environmental issues:
   -Reduces environmental problems caused by the extraction of metals
   -Prevents the dumping of rusty metals
3. Costs:
   Cheaper as it requires less energy than extracting new metal from ores.

Question 5

What are some disadvantages of recycling metals?

Answer 5

1. Pollution:
   - Smelting process during metal recycling of metals can produce harmful metal fumes,
2. Social Issues:
   - Effort and time invested in educating communities and businesses to practice recycling.
3. Costs
   - Recycling can be more expensive than extracting metals directly from ores.
   - Costs incurred in collecting, sorting, separating, cleaning, transporting

Question 6

What are the differences between high and low carbon steel?

Answer 6

Low– Hard, strong and malleable

High– Strong but brittle