Stuff

Question 1

Why is silicon dioxide a solid at room temp

Answer 1

Giant covalent lattice
Many strong covalent bonds
Take a lot of energy to overcome

Question 2

Why is carbon dioxide a gas at room temp

Answer 2

Simple covalent molecule
Weak intermolecular forces
Take little energy to over come

Question 3

Steps for titration

Answer 3

Add 25cm^3 of acid to conical flask and add drops of phenothanlene
Fill burette with alkali
Drip alkali solution into conical flask until it turns pale pink
Repeat with same volumes but no indicator
Evaporate off water

Question 4

Steps for excess base

Answer 4

Warm acid in beaker
Add metal oxide/carbonate and stir until stops dissolving
Filter
Boil off water until crystals start to form
Leave to cool and crystallise
Filter out crystals
Dry on filter paper

Question 5

Steps for precipitation

Answer 5

Mix solution of sodium salt and non-metal + metal nitrate solution
Filter
Wash with distilled water
Dry in warm oven

Question 6

Name conditions for both methods of making ethanol

Answer 6

Steam and ethene
300°c, pressure of 60-70 atm, phosphoric acid catalyst and steam
Fermentation
Anaerobic conditions at 30°C

Question 7

Name and method for breaking longer chain fractions into shorter ones

Answer 7

Cracking
Passing alkane over silica or alumina catalyst at 600-700°c

Question 8

Effect temp has on rate of reaction

Answer 8

At higher temp particulate have more kinetic energy
The collide more frequently and at a greater proportion with energy greater than activation energy
Rate of reaction increases

Question 9

Effect of concentration or pressure on rate of reaction

Answer 9

More partials in given volume
More frequent collisions
Increase in rate of reaction

Question 10

Effect of surface area on rate of reaction

Answer 10

The greater the surface area the more particles available for collisions
More frequent collisions, more frequent successful collisions
Increase rate of reaction

Question 11

Describe the purpose of a catalyst

Answer 11

Increase rate of reaction by providing an alternate route of lower activation energy
This means that frequency of collisions doesn’t change but the proportion of successful collisions increases so the frequency of successful collisions increases

Question 12

Define ionic bond

Answer 12

SEFABOCI

Question 13

Define metallic bond

Answer 13

SEFAB a giant lattice of metal ions and a sea of delocalised elections

Question 14

Define covalent bonding

Answer 14

SEFAB 2 atoms nuclei and a shared pair of electrons