Question

a scientist is determining the mass of 33,000 molecules of oxygen. use this to answer parts a and b. the mass of one molecule of oxygen = 5.3×10⁻²³ gram. a. how many significant digits should be in the solution? there should be 2 significant digits in the solution. (type a whole number.) b. express the mass of 33,000 molecules of oxygen in scientific notation. grams (type your answer using the appropriate number of significant digits. type your answer in scientific notation using the appropriate symbol from the math palette for any multiplication.)

Explanation:

Step1: Calculate total mass

Multiply number of molecules by mass of one molecule. So, $33000\times(5.3\times 10^{-23})$.
First, rewrite $33000$ as $3.3\times 10^{4}$. Then the calculation is $(3.3\times 10^{4})\times(5.3\times 10^{-23})$.
Using the rule of exponents $a^{m}\times a^{n}=a^{m + n}$, we have $(3.3\times5.3)\times10^{4+( - 23)}=17.49\times10^{-19}$.

Step2: Adjust to scientific - notation with correct significant digits

Since we need 2 significant digits, round $17.49$ to $17$. And rewrite $17\times10^{-19}$ as $1.7\times 10^{-18}$.

Answer:

$1.7\times 10^{-18}$ grams