Find the number of molecules in the given quantity of a compound whose molar mass is given. Express your answer in scientific notation, rounding the decimal part to the nearest hundredth.
-50 grams of carbon monoxide (CO); molar mass: 28.01 grams
A) $1.07 \times 10^{23}$ molecules
B) $8.43 \times 10^{26}$ molecules
C) $8.43 \times 10^{27}$ molecules
D) $1.07 \times 10^{24}$ molecules

Question

Quizplus · Accepted Answer

To find the number of molecules, first calculate the number of moles of CO: $50 \, \text{grams} \div 28.01 \, \text{grams/mole} = 1.785 \, \text{moles}$. Then, use Avogadro's number ($6.022 \times 10^{23}$ molecules/mole) to find the number of molecules: $1.785 \, \text{moles} \times 6.022 \times 10^{23} \, \text{molecules/mole} = 1.075 \times 10^{24}$ molecules.

Find the Number of Molecules in the Given Quantity of a Compound