Chemical Changes

Question 1

what is an electrolyte

Answer 1

a dissolved/molten ionic compound

Question 2

describe the general process of electrolysis

Answer 2

• ions in the electrolyte move towards the electrode
• positive ions move towards cathode & are reduced
• negative ions move towards anode & are oxidised
• this creates a flow of charge as ions move towards electrodes
• as ions gain/lose electrons, they form an uncharged element & are discharged from the electrode

Question 3

what are halides

Answer 3

• group 7 elements (ADD MORE INFO)

- Cl-, Br-, I-

Question 4

what happens if halides are present in electrolysis

Answer 4

if OH- and halide ions are present at the anode, molecules of Cl Br and I

Question 5

give the general word equation for the reaction of a metal carbonate and an acid

Answer 5

acid + metal carbonate –> salt + water + carbon dioxide

Question 6

give the general word equation for the reaction of an acid and a base (neutralisation)

Answer 6

acid + base –> salt + water

Question 7

explain how the products hydorgen, chlorine and sodium hydroxide solution are formed during the electrolysis of sodium chloride solution

Answer 7

• ions can move in solution
• H+ ions are atracted to the cathode & are reduced
• Cl- ions are attracted to the anode & are oxidised
• 2H+ + 2e- =>H2
• 2Cl- => Cl2 + 2e-
• H+ & Na+ ions are attracted to the cathode but the least reactive is formed (hydrogen)
• H+ & Cl- ions are discharged leaving NaOH solution
• Cl- is discharged in preference to OH-

Question 8

give the general IONIC equation for the reaction of an acid and a base (neutralisation)

Answer 8

H+ + OH- –> H2O

Question 9

give the general word equation for the reaction of a metal oxide and an acid

Answer 9

acid + metal oxide –> salt + water

Question 10

give the general word equation for the reaction of a metal hydroxide and an acid

Answer 10

acid + metal hydroxide –> salt + water

Question 11

give the general word equation for the reaction of a metal and water

Answer 11

metal + water –> metal hydroxide + hydrogen

Question 12

give the general word equation for the reaction of a metal and an acid

Answer 12

aid + metal –> salt + hydrogen

Question 13

give the order of the reactivity series

Answer 13

please (potassium)
stop (sodium)
loving (lithium)
callum (calcium)
murray (magnesium)
coz (carbon)
zach (zinc)
is (iron)
(a)
hotter (hydrogen) 
chap (copper)