experimental design

gas syringe

collect and measure the volume of gas in cm3

electronic balance

to measure mass in grams (usually copy all the numbers on the scale)

stopwatch

to measure time (usually recorded to nearest second)

thermometer

to measure temperature (to 10pm, .0 or .5)

dropper

to transfer small amounts of liquid

measuring cylinder

to measure liquid (to nearest cm3)

pipe the

to accurately measure out a fixed volume of liquid (25.0cm3, 20.0cm3)

burette

to accurately measure out a volume of liquid (to 2dp)

gases insoluble in water

hydrogen, helium, methane, carbon monoxide, nitrogen

gases soluble in water

ammonia, hydrogen chloride, nitrogen dioxide, sulfur dioxide, chlorine

slightly soluble: oxygen, carbon dioxide

collection of gas less dense than air

upward delivery

collection of gas denser than air

downward delivery

collection of gas insoluble in water

displacement of water

drying agents

concentrated sulfuric acid, quicklime (calcium oxide), fused calcium chloride

concentrated sulfuric acid

dry most gases except ammonia, acidic in nature so cannot dry alkali gases

quicklime (calcium oxide)

alkaline in nature, cannot dry acidic gas, used to dry ammonia

fused calcium chloride

dry most gases except ammonia, neutral

independent variable

the variable you change

dependent variable

the variable you measure

controlled variable

the variables kept the same