quantitative analysis Flashcards
when is a gas evolved in a reaction?
effervescence, colour/odour of gas is detected, when a solid substance is heated
what is the effect of oxygen on moist litmus paper?
no effect, oxygen gas is neutral
what are colourless and odourless gases that can be tested for?
oxygen, hydrogen, carbon dioxide
what is the effect of hydrogen gas on moist litmus paper?
no effect, hydrogen gas is neutral
what is the effect of carbon dioxide on moist litmus paper?
gas will turn moist blue litmus paper red, gas is acidic
what is the test for oxygen?
by inserting a glowing splint into the test tube, if the glowing splint is relit, oxygen is present
what is the test for hydrogen?
if a lighted splint is extinguished with a ‘pop’ sound, hydrogen is present
why does oxygen gas rekindle a lighted splint?
oxygen gas supports combustion
what is the test for carbon dioxide?
if bubbled gas in limewater forms a white precipitate, carbon dioxide is present
describe ammonia gas
colourless gas with a pungent smell
what is the test for ammonia gas?
if moist red litmus paper turns blue, ammonia gas is present (alkaline)
describe chlorine gas
greenish-yellow gas with a pungent smell
what is the reaction of chlorine gas with moist litmus paper and what is the conclusion?
will turn moist blue litmus paper to red and then bleached, gas is acidic
describe sulfur dioxide
colourless gas witha pungent smell
how does sulfur dioxide react with moist litmus paper?
turns moist blue litmus paper red (acidic)
how does Ca2+ react with aqueous sodium hydroxide?
white preciptate is formed which is insoluble in excess NaOH