Chemistry common

Question 1

Volume of one mole of gas

Answer 1

1 mole of any gas at 20℃ occupies 24dm³

Question 2

How do you go from dm³ to cm³

Answer 2

cm to dm is divide by 10
cm³ to dm³ is divide by 1000(10³)

goes cm, dm, meter

Question 3

What do acids and bases release in water

Answer 3

Acids H+ ions
Alkali OH-

Question 4

What does a strong acid mean

Answer 4

When react with water all the particles release H+ ions (H+ is just a proton)

Question 5

Why do strong acids increase rate of reaction

Answer 5

Strong acids release a lot of H+ ions
H+ ions used in reactions

Question 6

What is PH the measure of

Answer 6

PH measures the concentration of H+ or OH-ions

Question 7

Chemical formular of
Hydrochloric acid
Sulfuric acid
Nitric Acid

Answer 7

Sulfuric H₂SO₄
Hydrochloric HCl
Nitric HNO₃

Question 8

Difference between Alkali and base

Answer 8

Base is something that neutralises acids
Alkali is a base that is soluble in water(think alkali metals react to form alkali that is dissolved in water)

Question 9

What does Acid and a metal hydroxide produce and why

Answer 9

Makes a salt and water
water comes from H+ ion in acid and the OH- in the hyrdoxide

Question 10

What does Acid and metal oxide produce and why

Answer 10

Makes a salt and water
Water comes from H+ ion from acid and the O²- from the oxide

Question 11

What does an acid and a metal carbonate produce and why

Answer 11

Makes a salt and water and carbon dioxide
Water is produced for the same reason as a metal oxide and CO2 is produced from the carbonate

Question 12

Recall the reactivity series

Answer 12

Potassium, sodium, lithium, calcium, magnesium aluminium carbon zinc iron hydrogen copper silver gold

Question 13

Name for negative and positive electrode

Answer 13

Cathode is negative
Anode is positive

Question 14

Describe the products of electrolysis of a molten compund

Answer 14

Cryolite used to lower melting point ,the positive ion in the compound(e.g. Al³+) gets attracted to the cathode. The negative ion in the compound(O²-) gets attracted to the anode, if oxygen involved it reacts with the rods and produces CO2 using up the rod

Question 15

Describe the products of electrolysis in a aqueous solution

Answer 15

At cathode(-)
Water ionises and splits into H+ and OH-. At the cathode one of the two positive ion gets produced there ,either H+ or metal+ ion, the least reactive of the two gets produced at the cathode(tip because the more reactive one wants to stay in its compound)

At anode(+)
Oxygen(from OH-) will form and water unless a halide is present . The half equation for Oxygen is you start off with OH- ion and it turns to O₂ + H₂O + Electrons needs balancing

Question 16

Which of these is an alkali or a base

Metal Hydroxide
Metal Carbonate
Metal oxide

Answer 16

Metal hydroxide is alkali as it dissolves in water

Metal carbonate is base as it doesn’t dissolve in water

Metal Oxide base doesn’t dissolve in water (think copper oxide black powder that wont dissolve)

Question 17

How do you write an Ionic equation

Answer 17

Separate all the ions in the equation and write their products

Question 18

Describe structure of cell

Answer 18

Two electrodes that can conduct electricity in contact with an electrolyte(liquid that has free moving ions to conduct electricity)

Question 19

Why does a battery produce electricity

Answer 19

chemical reaction between electrodes and electrolyte make a charge difference between electrodes making electrons flow

Question 20

what effects cell voltage

Answer 20

difference in reactivity between metals
the electrolyte

Question 21

how to create battery

Answer 21

connect cells in series increases voltage

Question 22

Why do cells stop working

Answer 22

chemicals have all reacted so no voltage is produced

If rechargeable can apply current which reverses the reaction

Question 23

How does fuel cells work

Answer 23

hydrogen added to the -ve electrode and oxides loosing electrons and moves towards the +ve electrode through the electrolyte.
At +ve electrode the oxygen electrons and hydrogen ions react to form water