Ch - 14 (Metals and Alloys)

Question 1

What can the periodic table be divided into?

Answer 1

Metals and Non - metals

Question 1

What is it called if they display properties of both metal and non-metals?

Answer 1

Metalloids or semi metals

Question 2

What are the properties of metals?

Answer 2

• conduct heat and electricity
• malleable (hammered and made into different shapes)
• ductile (can be drawn into wires)
• Lustrous
• High density
• High m.p.
• Positive ion through electron loss
• Basic oxides

Question 3

What are the properties of non-metals?

Answer 3

• Do not conduct heat and electricity
• Brittle
• dull n non-reflective
• Low density
• low m.p.(mostly gases)
• negative ion cuz they gain electron(except H)
• Acidic oxides

Question 4

How can the chemical properties of metals be studied?

Answer 4

By analysing their reactions with:
- Water
- Dilute acid
- Oxygen

Question 5

What happens when metal reacts with cold water?

Answer 5

Metal + Water –> Metal hydroxide + Hydrogen

Question 6

What about metals that react with steam?

Answer 6

Metal + Steam –> Metal oxide + Hydrogen

Question 7

What happens when metal reacts with acids?

Answer 7

• Hydrogen atom in the acid is replaced by metal atom

Question 8

What is the equation when metal reacts with acids?

Answer 8

Metal + Acid –> Salt + Hydrogen

Question 9

What are the uses of aluminium?

Answer 9

• Aeroplane body (High strength to weight ratio, low density)
• overhead power cables (good conductor of electricity)
• Saucepans (Good conductor of heat)
• Food cans ( Non-toxic, resistant to corrosion and acidic food stuff)
• Window frames (Resistant to corrosion)

Question 10

What are the uses of copper?

Answer 10

-Electrical wires (Good conductor of electricity and malleable)

• Water pipes (Ductile, and doesn’t react with H2O)

Question 11

What is an alloy?

Answer 11

Alloy is a mixture of two or more metals and non-metals such as carbon

Question 12

What type of properties do alloys have?

Answer 12

• Different from metals
• More strength
• Hardness
• resistant to corrosion
• extreme temp
• More useful than pure metals

Question 13

What are some common alloys?

Answer 13

• Brass (copper and zinc)
• Stainless steel (mixture of iron, carbon, chromium and nickel)

Question 14

What is the use of brass?

Answer 14

• Stronger than either metal
• Musical instruments
• ornaments
• door knobs

Question 15

What is the use of stainless steel?

Answer 15

• ## cutlery (cuz hardness and resistance to corrosion)

Question 16

What is the use of the alloys of iron and tungsten?

Answer 16

• Hard
• Resistant to High temp.

Question 17

What is a property of an alloy of iron mixed with chromium and nickel?

Answer 17

Resistant to corrosion

Question 18

What is the use of aluminium mixed with copper, manganese and silicon?

Answer 18

• Aircraft body (strong alloy)
• low density

Question 19

Why is the arrangement of alloys different than of metals?

Answer 19

• Different sized atoms
• Distorts the regular arrangement of atoms

Question 20

Why are alloys much harder than pure metals?

Answer 20

• Different sized atoms
• Harder for layers to slide over each other.