Do NOT just memorize the answer key.  The answer key contains some notes to the examiner, and some of the symbols mean different things.  Read the following before checking answer keys:

• A slash '/' means "or"
• A semicolon (;) means that that sentence is worth one mark [1]
• OWTTE means "Or words to that effect."  Do not write this on your exam.  It is a note to the teacher correcting your test, which means that if you explain your answer correctly, but use different words, you will still get the points.
• "ecf" means "Error carried forward."  This is a good thing for you.   If you make a mistake earlier in a problem--for example, you calculate the molar mass incorrectly--and you use the same number or information to do another step in a problem, you will not lose points for it, unless it says differently in the mark scheme/answer key.
• Significant figures.  You can only lose one point/mark for significant figures on paper 2 and paper 3.  If you make a mistake in significant figures in the short answer, you will lose one mark.  If you make another mistake with significant figures, you will not lose any points!
• Show your work.  Sometimes you are only given marks/points for the final answer in calculations.  However, if you're wrong, you can usually get most marks/points for showing your calculations.
• Units do not usually matter, but include them just in case.