general chem Flashcards
What do you call a liquid that has no colour
Colourless solution
What is the observation for test for hydrogen gas
Effervescence occurs
Colourless and odourless gas evolved
Gas extinguishes lighted splint with a “pop” sound
Gas is hydrogen
What is the observation for test for carbon dioxide
Effervescence occurs
Colourless and odourless gas evolved
Gas forms white precipitate with limewater
Gas is carbon dioxide
What is the observation for test for ammonia gas
No effervescence is observed
Colourless and pungent gas evolved
Gas turns damp red litmus paper blue
Gas is ammonia
What is the procedure for testing for hydrogen gas after mixing the metal and the acid
Put a lighted splint at mouth of test tube
What is the procedure for testing for carbon dioxide after mixing the metal carbonate and the acid
Cover the mouth of the test tube with a stopper that carries a delivery tube. Dip opening end of the delivery tube into test tube containing limewater
What is the procedure for testing for ammonia gas after mixing the ammonium salt and the alkali
Warm mixture gently over a Bunsen flame
Add a drop of water to each piece of red and blue litmus. Hold red and blue litmus papers over mouth of test tube, taking care not to let the litmus paper touch the test tube
Why is it that when testing for ammonia gas we should not let the litmus paper touch the mouth of the test tube
To ensure that the litmus paper does not get contaminated by any substances on the test tube and that it only reacts with the gas produced
Suggest a reason why warming is needed to liberate the gas
Ammonia gas is soluble in water
What is the procedure for carrying out neutralization after mixing the acid and alkali
Heat up the mixture in an evaporating dish over a Bunsen flame until all the liquid evaporates, Allow evaporating dish to cool
