test of gases/water

Question 1

test for water chemical

Answer 1

anhydrous copper sulfate, put it in solution and will turn blue if water is present

Question 2

test for water physical

Answer 2

boil water, if it boils at exactly 100 degrees it is pure water, if not, it is not water or impure water

Question 3

test for CO2

Answer 3

lime water will go cloudy, emulsion

Question 4

test for O2

Answer 4

relight a glowing splint

Question 5

test for H2

Answer 5

makes a squeaky pop if near a lit splint is put near

Question 6

test for chlorine

Answer 6

turns blue litmus paper white

Question 7

test for ammonia

Answer 7

turns red litmus paper blue

Question 8

using iron wool, describe one way to determine % oxygen in the air

Answer 8

put iron wool in the test tube wet with water. put upside down in a beaker of water. Mark initial height of water and leave for a week measure new height and calculate percentage change

Question 9

using phosphorus/copper determine the % of oxygen in the air

Answer 9

glass tube containing phosphorus/copper, attached to one syringe full of air and one empty. measure the amount of air in the syringe. heat the phosphorus/copper and push the air back and forth reacting the oxygen with the phosphorus/copper. measure remaining air in syringe and calculate percentage change

Question 10

percentage change

Answer 10

difference÷original × 100