## General Chemistry: Principles and Modern Applications (10th Edition)

a) 3985 b) 442.0 c) $1.860\times10^{5}$ d) $3.390\times10^{4}$ e) $6.321\times10^{4}$ f) $5.047\times10^{-4}$
a) 3984.6 All the digits are significant since they are not zero. So to express this number in four significant figures, one has to round it to 4 digits, which is 3985. b) 442.04 All the digits are significant, since they are nonzero digits or zeros between nonzero numbers. So to round it to 4 significant figures, one has to round it to 4 digits, which is 442.0 c) 186,000 All the digits are significant, since they are nonzero digits or zeros at the end of a number. So to round it to 4 significant figures, one has to round it to 4 digits. This is only possible with the exponential notation, which is $1.860\times10^{5}$. d) 33,900 All the digits are significant, since they are nonzero digits or zeros at the end of a number. So to round it to 4 significant figures, one has to round it to 4 digits. This is only possible with the exponential notation, which is $3.390\times10^{4}$. e) $6.321\times10^{4}$ All the digits are significant, since they are nonzero digits. To round it to 4 significant figures, one has to round it to 4 digits. This is already the case, so the answer is $6.321\times10^{4}$. f) $5.0472\times10^{-4}$ All the digits are significant, since they are nonzero digits or zeros between nonzero numbers. So to round it to 4 significant figures, one has to round it to 4 digits, which is $5.047\times10^{-4}$