Multiple mark questions

Question 1

Why does Magnesium have a higher melting point than Sodium?

Answer 1

1. Both have metallic bonding
2. Show understanding of metallic bond
3. Say why attraction differs in strength
4. Link attraction strength to energy needed to break it
5. Link energy required to melting point

Question 2

Why does Potassium have a lower melting point than Sodium

(decreases going down group 1)

Answer 2

1. Both have metallic bonding
2. Show understanding of metallic bond
3. Say why attraction differs in strength
4. Link attraction strength to energy needed to break it
5. Link energy required to melting point

Question 3

Why do boiling points of Noble Gases increase going down group

Answer 3

1. More electrons in atoms leads to greater cloud wobble
2. leads to greater separation of charge and larger dipoles
3. Electrostatic attraction between dipoles increases
4. requires more energy to break them
5. Boling points increase

Question 4

Why do boiling points of halogens increase going down group?

Answer 4

1. More electrons in molecules leads to greater cloud wobble

2. leads to greater separation of charge and larger dipoles

3. Electrostatic attraction between dipoles increases

4. requires more energy to break them

5. Boling points increase

Question 7

Why does sulphur have a higher melting point than phosphorous?

Answer 7

• Sulphur exists as S₈ molecules and phosphorous as P₄
• Greater number of electrons in molecule leads to greater dipoles
• Electrostatic attractions is therefore larger between di[poled molecules and requires more energy to break them
• Melting point is therfore higher

Question 8

What are the 6 points needed to be covered to explain difference in melting points of fats and oils?

Answer 8

1. Level of unsaturation (C=C bonds)
2. Effect this has on tuning fork shape
3. Effect this has on how close they can pack together
4. Effect this has on intermoleular (LDF) attractions
5. Level of energy need to break them
6. corresponding lower or higher melting point

Question 9

How do soaps work?

Answer 9

•soaps have a polar head (COO ^_) and a non polar hydrocarbon tail

•the polar head can dissolve in water and the non polar tail can dissolve in oils and grease

•The soap surrounds the oil or grease and the polar head hydrogen bonds to water so dissolves, keeping the droplet of grease in suspension

Question 10

Answer 10

Question 11

Answer 11

Question 12

Answer 12

Question 13

Answer 13

Question 14

Answer 14