Question

How many molecules are in 7.4 g of potassium phosphate

Answer 1

Answer:
`0.21* 10^(22)` molecules of potassium phosphate

Step-by-step explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
`6.023* 10^(23)` of particles.

To calculate the moles, we use the equation:

`\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}=(7.4g)/(212g/mol)=0.035moles`

1 mole of potassium phosphate contains =
`6.023* 10^(23)` molecules

0.035 mole of potassium phosphate contains =
`(6.023* 10^(23))/(1)* 0.035=0.21* 10^(23)` molecules

Thus there are
`0.21* 10^(23)` molecules of potassium phosphate