preparation, testing gasses Flashcards
what needs to be reacted to make carbon dioxide gas
give reaction
calcium carbonate chips + dilute hydrochloric acid
CaCO3 + 2HCL —> CaCl2 + H2O + CO2
what needs to be reacted to make hydrogen gas
give reaction
pieces of zinc + dilute hydrochloric acid
Zn + 2HCl —> ZnCl2 + H2
what needs to be reacted to make oxygen gas
give reaction
catalyst?
break down of hydrogen peroxide in presence of manganese (IV) oxide catalyst
2H2O2 —-> 2H2O + O2
how to prepare ammonia gas
heat any ammonia compound with a base (NaOH, CaOH) both in solid form
when to use upward displacement to collect the gas
when the gas is heavier than air
when to use downward displacement to collect the gas
when the gas is lighter than air
when to use over water method
when the gas is sparingly soluble in water
when to use gas syringe
when we want to accurately measure the volume
what is the apparatus used when using upward displacement to collect the gas
gas jar
what is the apparatus used when using the over water method to collect the gas
gas jar, trough and water
what is the apparatus used when using the gas syringe method
gas syringe
examples of gasses we can collect in the upward displacement method
CO2, SO2, HCl
examples of gasses we can collect in the downward displacement method
NH3, H2
examples of gasses we can collect in the over water method
CO2, H2, O2
examples of gasses we can collect using gas syringe
any
ammonia gas test and result
test: hold damp red litmus in the gas
result: indicator paper turns blue
properties of ammonia gas
colourless alkaline gas with a strong sharp smell
carbon dioxide gas test and result and reaction
test: bubble the gas through limewater
result: limewater turns cloudy/milky
CO2 + Ca(OH)2(limewater) —> CaCO3 + H2O
properties of carbon dioxide
carbon dioxide is a colourless, weakly acidic gas. Reacts with limewater to form a white precipitate.
chlorine gas test and result
test: hold damp indicator paper in the gas
result: indicator paper bleaches (turns white)
properties of chlorine
chlorine is a green poisonous gas which bleaches dye
hydrogen gas test and result
test: collect the gas in a test tube and hold a lighted splint to it
result: gas burns with a squeaky pop
properties of hydrogen
hydrogen is a colourless gas which combines violently with oxygen when lit
oxygen gas test and result
test: collect gas in a test-tube and hold a glowing splint to it
result: glowing splint bursts into flames
properties of oxygen
oxygen is a colourless gas. fuels burn more more readily in it than air
sulfur dioxide test and result
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
upward method, downward method and overwater method are used for what
to collect and NOT to measure
