Place the gas in Limewater and if it is Carbon Dioxide the limewater should go cloudy.
Carbon Dioxide turns lime water milky/cloudy.
Put a formula into a test tube use a pep-et to transfer the gas from that tube, into the next test tube which is filled with lime water (not all the way to the top) bubble gas through the lime water,...
Bubbling through limewater. The gas is present if the limewater turns cloudy :)
by the process of photosynthesis
add lime water to the air if the lime water turns cloudy then carbon dioxide is present