Question

1. what is the mass of 30,000 molecules? express your answer in scientific notation. mass of one molecule of oxygen = 5.3×10^(-23) gram

Explanation:

Step1: Convert 30,000 to scientific notation

$30000 = 3\times10^{4}$

Step2: Multiply by mass of one molecule

$(3\times 10^{4})\times(5.3\times 10^{-23})$
Using the rule $a^{m}\times a^{n}=a^{m + n}$ and $(a\times b)\times(c\times d)=(a\times c)\times(b\times d)$, we have $(3\times5.3)\times(10^{4}\times10^{-23}) = 15.9\times10^{4+( - 23)}=15.9\times10^{-19}$

Step3: Adjust scientific - notation

$15.9\times10^{-19}=1.59\times10^{-18}$

Answer:

$1.59\times 10^{-18}$ grams