AQA GCSE CHEMISTRY Unit 1 Question Game!

Original post by whyaqawhy

Right mark me as harsh as possible please.

1. Extracting metals using reduction requires less energy than electrolysis as electrolysis requires large amounts of electricity, whereas extracting metals using reduction ie using carbon in a blast furnace requires less energy. The metal extracted from reduction is also brittle and metals extracted from electrolysis are more pure than reduction process.

2. Electrolysis produces much more pure metal - idk what else to write lol
3. Bioleaching - using bacteria , Phytoming? or blast furnace reduction with scrap iron.
4. metal atoms are arranged in layers which can slide(all atoms are same), however in an alloy, the layers become distorted, making it hard for the atoms to slide, making the alloy harder ( due to different size atoms from different elements added)

1 - A very good answer from what I can see. I'm not quite sure about the metals from reduction always being brittle as that isn't always the case, I think.

2- Electrolysis uses electricity - expensive. Also, electrolysis often needs the metal to be molten which is also expensive as you need fossil fuels and it isn't environmentally friendly. However, electrolysis purifies the metal in a much shorter time.

On the other hand, displacement is cheap as you often use scrap iron which would otherwise go to waste. - Idk anything to say about the displacement LOL - I expected you to give me some so that I could revise this xD. Can anyone else help?

3- You have to describe the methods in depth. Not just state them. Probably would get 1/2 marks if this came up as a 6 marker. Instead, you should describe the methods so: Bioleaching is when we use bacteria to get copper from lowgrade ores as opposed to the traditional method being reduction with carbon from high grade ores as the copper is running out.
The bacteria is grown on lowgrade ores and it gets energy from the bond between copper and sulfur in copper sulfide, it then uses that energy to separate the copper into a copper sulfate solution. This copper sulfate solution can then be purified using scrap iron to displace the copper or electrolysis.
On the other hand, phytomining is when plants are grown in soil containing lowgrade copper ores. The plants take the copper in and store it. They can then be harvested, dried and burnt. From the ashes, you can get the copper by purifying it using electrolysis or using scrap iron once you make a solution of copper sulfate.

4- Perfect answer. Good work!

Reply 271

Original post by tamanna___

Explain miller and ureys theory.

Include why theory only provided weak evidence

Miller and Urey's theory was that, in the early atmosphere, the substances present called primate gases being ammonia, methane, hydrogen, water vapour and nitrogen formed life.

The theory provided weak evidence as, when they did the experiment, the amount of amino acids was too little for it to have created life. So, Miller and Urey were on the right lines but the question of how exactly do you create life from the amino acids still remains till this day.

Reply 272

Love123443

6

Hey how was the earths early atmosphere formed?

Reply 273

Original post by jackbarry1999

how are hydrocarbons cracked

A long-chain hydrocarbon is too long to be of any significant use, so we need to break it down in the process of 'cracking'. We heat the long-chain hydrocarbon and this creates shorter chained hydrocarbons, which can be used for fuel and an alkene.

Reply 274

RubiksNinja

7

Original post by Dxua

what is the lime cycle?

Calcium Carbonate (CaCO3) thermally decomposes to give you Calcium oxide + water.

CaCO3 ----- (HEAT) -----> CaO +CO2

Calcium oxide reacts with water to produces calcium hydroxide

CaO +H2O -> Ca(OH)

Both calcium hydroxide and calcium oxide are alkali so can be used to neutralise acidic soils and lakes

Calcium hydroxide added with more water gives you calcium hydroxide (aqueous). Also known as limewater.

Limewater + Carbon dioxide gives you Calcium carbonate. This is actually the test for carbon dioxide as the limewater turns cloudy. The cloudy colour is made because the calcium hydroxide (limewater) reacting with the carbon dioxide to give little solid pieces of calcium carbonate which is white in colour.

The equation for that is:

Ca(OH) + CO2 -> CaCO3 + H20

Reply 275

Original post by MaxHSloan

What are the conditions needed to harden vegetable oils?

- Nickel catalyst
- 60 degrees celsius
- An alkene (unsaturated) mixed with hydrogen

Reply 276

Original post by Love123443

Explain the theory of contential drift?

This was a theory brought about by Wegener. It suggested that over millions of years, the continents have drifted from being one large land space to the formation we know today.

Reply 277

Original post by RubiksNinja

Calcium Carbonate (CaCO3) thermally decomposes to give you Calcium oxide + water.

CaCO3 ----- (HEAT) -----> CaO +CO2

Calcium oxide reacts with water to produces calcium hydroxide

CaO +H2O -> Ca(OH)

Both calcium hydroxide and calcium oxide are alkali so can be used to neutralise acidic soils and lakes

Calcium hydroxide added with more water gives you calcium hydroxide (aqueous). Also known as limewater.

Limewater + Carbon dioxide gives you Calcium carbonate. This is actually the test for carbon dioxide as the limewater turns cloudy. The cloudy colour is made because the calcium hydroxide (limewater) reacting with the carbon dioxide to give little solid pieces of calcium carbonate which is white in colour.

The equation for that is:

Ca(OH) + CO2 -> CaCO3 + H20

Calcium hydroxide is Ca(OH) with a small 2 after the (OH). You would potentially lose a mark if you wrote down Ca(OH)

Reply 278

Original post by NoahSwinden

- Nickel catalyst
- 60 degrees celsius
- An alkene (unsaturated) mixed with hydrogen

is vegetable oil an alkene?

Reply 279