preparation, testing gasses

Question 1

what needs to be reacted to make carbon dioxide gas
give reaction

Answer 1

calcium carbonate chips + dilute hydrochloric acid

CaCO3 + 2HCL —> CaCl2 + H2O + CO2

Question 2

what needs to be reacted to make hydrogen gas
give reaction

Answer 2

pieces of zinc + dilute hydrochloric acid

Zn + 2HCl —> ZnCl2 + H2

Question 3

what needs to be reacted to make oxygen gas
give reaction
catalyst?

Answer 3

break down of hydrogen peroxide in presence of manganese (IV) oxide catalyst
2H2O2 —-> 2H2O + O2

Question 4

how to prepare ammonia gas

Answer 4

heat any ammonia compound with a base (NaOH, CaOH) both in solid form

Question 5

when to use upward displacement to collect the gas

Answer 5

when the gas is heavier than air

Question 6

when to use downward displacement to collect the gas

Answer 6

when the gas is lighter than air

Question 7

when to use over water method

Answer 7

when the gas is sparingly soluble in water

Question 8

when to use gas syringe

Answer 8

when we want to accurately measure the volume

Question 9

what is the apparatus used when using upward displacement to collect the gas

Answer 9

gas jar

Question 10

what is the apparatus used when using the over water method to collect the gas

Answer 10

gas jar, trough and water

Question 11

what is the apparatus used when using the gas syringe method

Answer 11

gas syringe

Question 12

examples of gasses we can collect in the upward displacement method

Answer 12

CO2, SO2, HCl

Question 13

examples of gasses we can collect in the downward displacement method

Answer 13

NH3, H2

Question 14

examples of gasses we can collect in the over water method

Answer 14

CO2, H2, O2

Question 15

examples of gasses we can collect using gas syringe

Answer 15

any

Question 16

ammonia gas test and result

Answer 16

test: hold damp red litmus in the gas
result: indicator paper turns blue

Question 17

properties of ammonia gas

Answer 17

colourless alkaline gas with a strong sharp smell

Question 18

carbon dioxide gas test and result and reaction

Answer 18

test: bubble the gas through limewater
result: limewater turns cloudy/milky
CO2 + Ca(OH)2(limewater) —> CaCO3 + H2O

Question 19

properties of carbon dioxide

Answer 19

carbon dioxide is a colourless, weakly acidic gas. Reacts with limewater to form a white precipitate.

Question 20

chlorine gas test and result

Answer 20

test: hold damp indicator paper in the gas
result: indicator paper bleaches (turns white)

Question 21

properties of chlorine

Answer 21

chlorine is a green poisonous gas which bleaches dye

Question 22

hydrogen gas test and result

Answer 22

test: collect the gas in a test tube and hold a lighted splint to it
result: gas burns with a squeaky pop

Question 23

properties of hydrogen

Answer 23

hydrogen is a colourless gas which combines violently with oxygen when lit

Question 24

oxygen gas test and result

Answer 24

test: collect gas in a test-tube and hold a glowing splint to it
result: glowing splint bursts into flames

Question 25

properties of oxygen

Answer 25

oxygen is a colourless gas. fuels burn more more readily in it than air

Question 26

sulfur dioxide test and result

Answer 26

test: soak a piece of filter paper in acidified aqueous potassium manganate place it in the gas (acidified means a little dilute acid has been added usually hcl)
result: colour on paper changes from purple to colourless

Question 27

upward method, downward method and overwater method are used for what

Answer 27

to collect and NOT to measure