Chemistry SC10-SC14

Question 1

A) What is electrolysis?
B) What is required for it to work?

Answer 1

A) The process of breaking down a compound into elements using electricity
B) The ions must be able to move freely, so the electrical current can flow around a circuit

Question 2

What is an electrolyte?

Answer 2

A liquid that contains freely moving ions

Question 3

State what colour the following indicators turn when in; Acidids, Alkalines & Neutral Solutions;
A) Litmus Paper
B) Methyl Paper
C) Phenolphthalein

Answer 3

A) Litmus Paper
- Acid: Red
- Neutral: Purple
- Alkaline: Blue

B) Methyl Orange
- Acid: Red
- Neutral: Yellow
- Alkaline: Yellow

C) Phenolphtalein
- Acid: Colourless
- Neutral: Colourless
- Alkaline: Pink

Question 4

List the the ionic compounds that would form if they’re;
A) Soluble
B) Insoluble

Answer 4

A) All common sodium, potassium and ammonium salts, All nitrates

A2) Most common chlorides, Most common sulfates, Sodium hydroxide, potassium hydroxide, ammonium hydroxide

B1) Silver chloride, lead chloride, Lead sulfate, barium sulfate, calcium sulfate, Most common carbonates

B2) Most common hydroxides

Question 5

When it comes to equilibrium, what effect does the following have;
A) Increasing/Decreasing Temp
B) Increasing/Decreasing Pressure
C) Increaing/Decreasing Concentration

Answer 5

A1) Increasing Temp: Shifts in the endothermic direction
A2) Decreasing Temp: Shifts to the exothermic direction

B1) Increasing Pressure: Shifts in the direction that forms fewer molecules/moles.
B2) Decreasing Pressure: Shift in the direction that forms more molecules/moles.

C1) Increasing Concentration: Shift in the direction that uses up the substance that was added
C2) Decreasing Concentration: Shifts in the direction that forms more of the substance that has been removed.

Question 6

What is;
A) Phytoextraction
B) Bioleaching
( Include Advantages & Disadvantages )

Answer 6

1. Phytoextraction: Copper ions are absorbed by the plants roots. Copper is concentrated as the plant grows, The plants are burned, & copper is extracted.
- Advantages: Metals cam be extracted from contaminated soil
- Disadvantages: Plants require right conditions to grow

2. Bioleaching: Baceria is grown on low grade ore, The bacteria break down the ore & produces a solution containing copper ions called leachate. Scrap iron can be used to displace the copper from the leachate.
- Advantages: - Does not require high temperatures. Reduces waste from scrap iron.
- Disadvantages: - Produces toxic chemicals which harm enviroment.

Question 7

Alloying

What are the effects of the following alloys?
A) Carbon
B) Copper
C) Chomium

Answer 7

A) Improves the hardness, tensile strength & hardenability of steel.

B) Used in high-strength steels, which are often used in shipbuilding.

C) Provides high hardness & corrosion resistance.

Question 8

What are some chemical properties of transition metals.

Answer 8

1. Usually Coloured
- Due to having differently arranged electrons in the outershell. Visible light interacts with electrons so some wavelengths are absorbed.

2. Usually show catalytic activity.