Question

5.) how many molecules is 3.50 g co₂? (1 point)
4.79×10²² molecules co₂
1.44×10²³ molecules co₂
0.0795 molecules co₂
44 molecules co₂

Explanation:

Step1: Calculate molar mass of CO₂

The molar mass of C is 12.01 g/mol and O is 16.00 g/mol. For CO₂, molar mass $M = 12.01+2\times16.00=44.01$ g/mol.

Step2: Calculate number of moles

The number of moles $n=\frac{m}{M}$, where $m = 3.50$ g and $M = 44.01$ g/mol. So $n=\frac{3.50}{44.01}\approx0.0795$ mol.

Step3: Calculate number of molecules

We know that 1 mole of any substance contains $N_A = 6.022\times 10^{23}$ molecules. So the number of molecules $N=n\times N_A=0.0795\times6.022\times 10^{23}\approx4.79\times 10^{22}$ molecules.

Answer:

$4.79\times 10^{22}$ molecules CO₂