chemical changes

Question 1

what does litmus form in acidic solutions

Answer 1

red

Question 2

what does litmus paper form in neutral solutions

Answer 2

purple

Question 3

what does litmus paper form in alkaline solution

Answer 3

blue

Question 4

what does methyl orange form in acidic solutions

Answer 4

red

Question 5

what does methyl orange form in neutral solutions

Answer 5

yellow

Question 6

what does methyl orange form in alkaline solutions

Answer 6

yellow

Question 7

what does phenolphthalein form in acidic and neutral solution

Answer 7

colourless

Question 8

what does phenolphthalein form in alkaline solutions

Answer 8

pink

Question 9

what are strong acids

Answer 9

they ionise(dissociate) completely in water to release H+ ions

Question 10

what are weak acids

Answer 10

they dont dissociate completely in water to release H+ ions

Question 11

what impact does the amount of H+ ions have on the pH of the acid

Answer 11

if the concentration of H+ ions increase by a factor of 10, the pH decreases by 1.

Question 12

are common salts of sodium, potassium, and ammonium soluble or insoluble

Answer 12

soluble

Question 13

are nitrates soluble or insoluble

Answer 13

soluble

Question 14

are common chlorides soluble or insoluble

Answer 14

soluble

Question 15

what are the only chlorides that are insoluble

Answer 15

silver and lead chloride

Question 16

are common sulfates soluble or insoluble

Answer 16

soluble

Question 17

what are the only sulfates that are insoluble

Answer 17

lead , barium and calcium sulfate

Question 18

are common carbonates and hydroxides soluble or insoluble

Answer 18

insoluble

Question 19

what are the only carbonates and hydroxides that are soluble

Answer 19

sodium, potassium and ammonium ones

Question 20

what is electrolysis

Answer 20

this is the separation of substances using electricity.

Question 21

which electrode do the cations go to

Answer 21

cathode

Question 22

which electrode do the anions go to

Answer 22

anode

Question 23

what should the electrolyte be to make sure electrolysis occurs

Answer 23

it should be a solution or molten

Question 24

in electrolysis, what substance goes to the cathode

Answer 24

metal

Question 25

in the electrolysis of aqueous solutions, what substances go to the cathode

Answer 25

H+ ions and metal ions

Question 26

in the electrolysis of aqueous solutions, what substances go to the anode

Answer 26

OH- and halide ions

Question 27

what can form at the cathode in the electrolysis of an aqueous solution

Answer 27

-hydrogen gas forms if metal is more reactive than hydrogen -solid layer of pure metal will form if it is less reactive than hydrogen

Question 28

what can form at the anode in the electrolysis of an aqueous solution

Answer 28

if halide is present, molecules of halide will be formed. if no halide is present, oxygen will be formed