Final answer:
To quantitatively observe the CO2 collected by yeast in balloons, a student can use volume marking on the balloons, water displacement, or pressure sensors to measure the gas volume. Consistent experimental conditions must be maintained for accurate comparison across different sugar amounts.
Step-by-step explanation:
To make quantitative observations of the CO2 collected in the balloons during a lab investigation into the respiration of sugars by yeast, a student can employ several different methods. The volume of gas can be measured by either using a balloon with marked graduations or by using water displacement to collect the gas in an inverted container and then measuring the volume of water displaced. In the latter case, the gas forces the water out of the container, and the volume of water displaced is equivalent to the volume of the gas. Another method involves using a gas pressure sensor to directly measure the pressure of the gas, which can then be used to calculate its volume using the ideal gas law.
A balanced chemical equation based on the described reaction would be essential for understanding the stoichiometry of the reaction. Moreover, to ensure accurate measurements, if the amount of gas is being compared across trials with varying amounts of sugar, it is critical that all other conditions, such as temperature, volume of yeast suspension, and type of sugar, are kept consistent.