Three separate samples of an unknown gas were bubbled through water and collected in a closed container of variable volume. The masses of the gas samples were determined by measuring the mass of the flask containing the pure gas before and after each introduction of gas into the water/sealed container apparatus. Given that the atmospheric pressure was 776.5mmHg throughout, and the vapor pressure of water at the experimental temperature was 21.2mmHg, calculate the molecular weight of the unknown gas: Trial 1 Trial 2 Trial 3 Temperature (oC) 24.5 23.8 23.8 Initial Mass 12.4510g 12.3585g 12.2802g Final Mass 12.3585g 12.2802g 12.1708g Volume collected 40.15mL 33.62mL 45.34mL

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.