gas tests

test for chlorine, ammonia, oxygen, carbon dioxide an hydrogen

what is the test for carbon dioxide?

bubble the gas through limewater

if carbon dioxide is present what happens to limewater?

limewater turns cloudy

if carbon dioxide is not present what happens to limewater?

limewater stays colourless

what is the test for chlorine gas?

place damp blue litmus paper in the test tube with gas

if chlorine is present what happens to the damp blue litmus paper?

damp blue litmus paper will turn red and then its bleached white

why does damp blue litmus paper turn red at first when chlorine is present?

because the chlorine gas reacts with water to form a slightly acidic solution

if chlorine is not present what happens to the damp blue litmus paper?

damp blue litmus paper stays blue

what is the test for hydrogen gas?

put a lighted splint into the test tube with gas

if hydrogen gas is present what happens?

hydrogen makes a squeaky pop sound

where does the squeaky pop sound come from when hydrogen is present?

it comes form the hydrogen burning with the oxygen in the air to form water

what is the test for oxygen?

place a glowing splint into a test tube with gas

what is the difference between lighted and glowing splint?

a lighted splint has no fire while a glowing splint has fire

if oxygen is present what happens?

the splint relights

what is the test for ammonia?

place damp red litmus paper near the mouth of the test tube of gas

if ammonia gas is present what happens to the damp red litmus paper?

the damp red litmus paper turns blue

why can’t you put the damp red litmus paper inside the test tube in the test for ammonia gas?

because If you are testing for ammonia produced from ammonium ions and sodium hydroxide, avoid touching the sides to prevent sodium hydroxide from also turning the red litmus paper blue