PAPER 1 unknown things

Question 1

What are the processes of making ground water potable?

Answer 1

• Filtration
• Sedimentation
• Chlorination

Question 2

What is deionised water?

Answer 2

Water that has had metallic ions removed.

Question 3

What three steps are required to produce a pure dry soluble salt from a soluble acid and alkali?

Answer 3

• Complete a titration to find the required amounts of each substance.
• Mix the reactants in the correct amounts.
• Evaporate the water from the solution, then dry the crystals.

Question 4

How do you carry out a titration?

Answer 4

• Use a pipette to add a measured volume of acid to a conical flask, then add a few drops of indicator. Place this on a white tile.
• Fill the burette with alkali, noting the initial volume.
• Turn on the tap so that the alkali slowly goes into the conical flask, drop by drop. Constantly mix the flask.
• As soon as the indicator changes colour, turn off the tap and record the final volume of alkali in the burette. Find the total amount of alkali used by subtracting the final volume from the initial volume.
• Repeat this process until you have concordant results.

Question 5

Are nitrates soluble?

Answer 5

Yes, no exceptions.

Question 6

Are chlorides soluble?

Answer 6

Yes, except silver and lead.

Question 7

Are sodium salts soluble?

Answer 7

Yes, no exceptions.

Question 8

Are ammonium salts soluble?

Answer 8

Yes, no exceptions.

Question 9

Are potassium salts soluble?

Answer 9

Yes, no exceptions.

Question 10

Are sulphates soluble?

Answer 10

Yes, except lead, calcium and barium.

Question 11

Are carbonates soluble?

Answer 11

No, except sodium, potassium and ammonium.

Question 12

Are hydroxides soluble?

Answer 12

No, except sodium, potassium and ammonium.

Question 13

How can electrolysis of copper sulphate be used to purify copper?

Answer 13

Use an impure copper anode and pure copper cathode in the solution and electrolyse it. The copper from the anode will move to the cathode, forming more pure copper.

Question 14

What do you get when a metal reacts with cold water?

Answer 14

Metal hydroxide + hydrogen

Question 15

What do you get when a metal reacts with steam?

Answer 15

Metal oxide + hydrogen

Question 16

What is done to aluminium oxide before its electrolysis?

Answer 16

It is dissolved in molten cryolite to give it a lower melting point and reduce the energy needed for electrolysis (aluminium has a very high melting point).

Question 17

How can plants be used to extract metals?

Answer 17

Phytoextraction:
- Plants are grown in small areas with metals in the soil.
- The plants take up metal ions in their roots.
- The plants are burned and metals are removed from the ash.

Question 18

How can bacteria be used as an alternative extraction method?

Answer 18

Bioleaching:
- Some bacteria absorb metal compounds.
- These bacteria produce solutions called leachates containing the metals.
- Scrap iron can be used to extract the metals from these leachates.

Question 19

What is a life cycle assessment?

Answer 19

An analysis of the overall environmental impact a product will have throughout its lifetime.

Question 20

What conditions are used in the Haber process?

Answer 20

• 450ºc
• 200atm
• iron catalyst

Question 21

What metal is used for the sacrificial protection of iron?

Answer 21

Zinc

Question 22

How does electroplating work?

Answer 22

• The metal being coated is the cathode
• The metal that is the coat is the anode
• The electrolyte must also contain ions of the metal that will be coating
• A power supply is connected to both electrodes

Question 23

What is magnalium?

Answer 23

An alloy of magnesium and aluminium. It is lighter and stronger than aluminium and more resistant to corrosion. It is used in cars and aircraft.

Question 24

What is brass?

Answer 24

An alloy of copper and zinc. It is hard and resistant to corrosion.

Question 25

What is Avogadro's Law about gas volumes?

Answer 25

At the same temperature and pressure, equal amounts of gas will occupy the same volume of space.

Question 26

What is the molar volume of gas?

Answer 26

The volume that one mole of any gas takes up at room temperature and pressure.

Question 27

Describe the steps carried out in the Haber process.

Answer 27

- The reactants are collected (hydrogen and nitrogen). - The gasses are compressed at 200 atm and heated to 450ºc before being pumped into a tank containing catalytic iron beads. - Ammonia forms. - The ammonia and unreacted reactants pass into a cooling chamber, where ammonia is collected as liquid. - The unreacted reactants are recycled back into the tank.

Question 28

What compounds are found in NPK fertilisers?

Answer 28

- Potassium - growth + healthy fruit - Nitrogen - healthy leaves - Phosphorus - healthy roots

Question 29

Which ammonium salt is most commonly used in fertilisers?

Answer 29

Ammonium nitrate (NH4NO3)

Question 30

How is a voltage produced from a chemical cell?

Answer 30

- Two metals of different reactivities are placed in an electrolyte. - The more reactive metal releases electrons, becoming positively charged. - These electrons flow to the other electrode, becoming negatively charged. - The difference in the ability of each electrode to release electrons causes the voltage to be produced.

Question 31

How does a hydrogen-oxygen fuel cell work?

Answer 31

- Hydrogen and oxygen are pumped though porous electrodes. - The electrolyte is often an acid such as phosphoric acid. - Hydrogen and oxygen react, producing electricity and water.

Question 32

What are the advantages of using fuel cells?

Answer 32

- No pollution - More energy produced - Continuous process

Question 33

What are the disadvantages of fuel cells?

Answer 33

- Materials to make them are expensive. - High pressure tanks are required for storage. - Hydrogen is expensive. - Efficiency is affected by temperature. - Hydrogen can be very explosive.