- C—After one half-life, 50% would remain. After
another half-life, this would be reduced by
one-half to 25%. The total amount decayed is
75%. Thus, 24.6 years must be two half-lives of
12.3 years each.
75. E—One mole of alkene, CnH 2 n, will form n
moles of water. It is possible to determine the
value of nby dividing the mass of the alkene by
the empirical formula mass.
318 STEP 5. Build Your Test-Taking Confidence
Count the answers you got correct. Then count the answers you got wrong (skip those you did not answer).
Multiply the number of wrong answers by 0.25 and subtract this value from the number of correct answers.
This gives you your score on this set of questions.