Question

How many molecules are there in 5.0 g of methyl alcohol, ch3oh?

Answer 1

Answer: $0.96\times 10^{23}$ molecules

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

given mass of methyl alcohol = 5.0 g

Molar mass of methyl alcohol = 32.04 g/mol

Putting in the values we get:

$\text{Number of moles}=\frac{5.0g}{32.04g/mol}=0.16moles$

1 mole of methyl alcohol $(CH_3OH)$ contains=6.022\times 10^{23}[/tex] molecules

Thus 0.16 moles of methyl alcohol $(CH_3OH)$ contain=$\frac{6.022\times 10^{23}}{1}\times 0.16=0.96\times 10^{23}$

molecules

Thus there are $0.96\times 10^{23}$ molecules in 5.0 g of methyl alcohol.