What is the molality of solution made by dissolving 100 g of bromothymol blue (C27H28Br2O5S) in 1L of ethanol on a winter's day at 10°C. The density of ethanol at this temperature is 0.7979kg/L?
Answers
Answer:
The molarity is
0.426 M
.
The molality is
0.434 m
.
Explanation:
We will need the moles ethanol for both calculations.
2.00
g C
2
H
5
OH
×
1
mol C
2
H
5
OH
46.069
g C
2
H
5
OH
=
0.043413 mol C
2
H
5
OH
I am leaving a couple of extra digits to reduce rounding errors. The final answers will be rounded to three significant figures.
MOLARITY
molarity
=
moles solute
L of solution
We need to convert
102 mL of solution
to
L
.
1 L
=
1000 mL
102
mL
×
1
L
1000
mL
=
0.102 L
molarity
=
0.043413 mol C
2
H
5
OH
0.102
L
=
0.426 mol C
2
H
5
OH/L
=
0.426 M
(rounded to three significant figures)
MOLALITY
molality
=
moles solute
kg solvent
Water is the solvent.
We need to convert
100.0 g
water to
kg
.
1 kg
=
1000 g
100.0
g
×
1
kg
1000
g
=
0.1000 kg
molality
=
0.043413
mol C
2
H
5
OH
0.1000
kg H
2
O
=
0.434 mol/kg
=
0.434 m
(rounded to three significant figures)
Answer:
Answer is 0.201 mol kg^-1
Explanation:
I hope it is helpful for you ......
Thank