PS#1.html

#3: 1 point for correctly explaining why hexane is Liquid #1 and 1 point for explaining why ethanol is not. The reason must be correctly explained for each point. All that must be said is hexane will form a heterogeneous mixture and ethyl alcohol will not. The explanation could be given in terms of solubility also. 1 point for selecting carbon tetrachloride for Liquid #2. Reasoning for this choice was not graded. If the reasoning is wrong, correct it, but do not deduct the point. Bromine is not a good choice because of its volatility and reactivity.
#7: 1 point for each part right or wrong. On this problem we are grading for the correct number of significant figures. The answer is either right or wrong. NOTE: my answers are right! Parts a) and c) are hard. Students had a hard time with part a). Click here for explanation.
#8: 1 point each for parts a), b), and c). Award the 1 point for the magnitude of the anwers. If any errors in significant figures or in missing or wrong units, correct but do not deduct from the score.