Question

1. How many atoms are there in 1.7 mol Ca?

Answer 1

answer: 3g. 17kg+3 ÷ 0.25

Answer 2

There are
`2.55*10^(23)` atoms in 1.7 mol Ca

Solution:

Initially we have to convert the given mass of calcium to moles of calcium, using its molar mass (referring to a periodic table, this is 40.08 g/mol

`1.7 \text { g Ca }\left(\frac{1 \text{ mol Ca}}{40.08 \text{ g Ca}}\right)= 0.0424 \text{ mol Ca}`

Using Avogadro's number,
`6.022 * 10^(23) \text{ particles per mol}` as
`1 \text{ mole }=6.022* 10^(23)`

We can calculate the number of atoms present by
`0.0424 \text{ mol Ca}*\frac{6.022 * 10^(23)}{1 \text{ mol }}=2.55*10^(23) \text { atoms Ca }`