39 g H
2
O
contains
1.3
×
10
24
molecules H
2
O
.
Explanation:
One mole of water has a molar mass of
18.015 g/mol
and
6.022
×
10
23
molecules H
2
O
. Therefore,
1 mol H
2
O
=
18.015 g H
2
O
=
6.022
×
10
23
molecules H
2
1O
Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.
39
g H
2
O
×
1
mol H
2
O
18.015
g H
2
O
×
6.022
×
10
23
molecules H
2
O
1
mol H
2
O
=
1.3
×
10
24
molecules H
2
O
39 g H
2
O
contains
1.3
×
10
24
molecules H
2
O
.
Explanation:
One mole of water has a molar mass of
18.015 g/mol
and
6.022
×
10
23
molecules H
2
O
. Therefore,
1 mol H
2
O
=
18.015 g H
2
O
=
6.022
×
10
23
molecules H
2
1O
Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.
39
g H
2
O
×
1
mol H
2
O
18.015
g H
2
O
×
6.022
×
10
23
molecules H
2
O
1
mol H
2
O
=
1.3
×
10
24
molecules H
2
O
39 g H
2
O
contains
1.3
×
10
24
molecules H
2
O
.
Explanation:
One mole of water has a molar mass of
18.015 g/mol
and
6.022
×
10
23
molecules H
2
O
. Therefore,
1 mol H
2
O
=
18.015 g H
2
O
=
6.022
×
10
23
molecules H
2
1O
Multiply the given mass of water times the conversion factors that cancel grams and moles of water, leaving molecules of water, as demonstrated below.
39
g H
2
O
×
1
mol H
2
O
18.015
g H
2
O
×
6.022
×
10
23
molecules H
2
O
1
mol H
2
O
=
1.3
×
10
24
molecules H
2
O