Chemistry
22.01.2021 15:01
269
464
10
Solved by an expert

3.2473 g of na2cro4 (mw = 161.97 g/mol) is dissolved in 100.0 ml of water. assuming

3.2473 g of na2cro4 (mw = 161.97 g/mol) is dissolved in 100.0 ml of water. assuming the solution has a density of 1.00 g/ml, what is the concentration of na (mw = 22.9898 g/mol) in the solution in units of (a) molarity (m)? (b) parts per thousand (ppt)? (c) 10.0 ml of the solution is then diluted to a final volume of 1000.0 ml. what is the concentration of na in the diluted solution in units of parts per million (ppm)?
Show Answers
holamigosss
holamigosss
4,5(49 marks)

a) 0.400 mol/L

b) 9.20 ppt

c) 91.96 ppm

Explanation:

The first step is considereing the dissociation of the salt in water:

Na₂CrO₄ (s) → 2Na⁺ (aq) + CrO₄²⁻ (aq)

This means that for every mol of Na₂CrO₄ 2 mol of Na⁺ will be produced.

a) molarity

C = \frac{n/ mol}{V / L} \\MW=\frac{m/g}{n/mol} \\C = \frac{m}{MW} .\frac{1}{V} \\\\

For Na₂CrO₄:

C = \frac{3.2473g}{161.97g/mol} .\frac{1}{0.1L} \\C = 0.200 mol/L

The molarity of Na will be the double of the molarity of the molarity of Na₂CrO₄:

C = 0.400 mol/L

b) parts per thousand (ppt)

m ppt = \frac{m}{1000 g} \\m = MW.n\\m ppt = \frac{MW.n}{1000g} \\m ppt = \frac{22.9898.0.04}{1000} \\\\m = 9.20 g\\\\Na: \frac{9.20 g}{1000 g solution} = 9.20 ppt

c) parts per million (ppm)

0.400 mol Na ____ 1000 mL solution

           x          ____  10 mL solution

x = 0.004 mol Na

The new solution has a concentration of Na of 0.004 mol/L.

ppm = mg/L

m=MW.n\\m = 22.9898 . 0.004\\m = 0.0916 g\\m = 91.6 mg\\\\Na = 91.96 ppm

arivalen
arivalen
5,0(43 marks)


Magnetic

Kinetic

Heat

Light

Gravitational potential

Chemical

Sound

Electrical

Elastic potential

Nuclear

Popular Questions about the subject: Chemistry

Which of the following is a unit for mass in the standard or...
Chemistry
28.09.2021 19:54
What element does this model represent? A Potassium B Sodium...
Chemistry
08.05.2020 19:27
Formula for Tungsten(V) Selenide...
Chemistry
16.11.2021 13:31
PLS HELP ME PUT IS IT PURE ELEMENT OR COMPOUD ASP !...
Chemistry
24.05.2021 23:22
Please and thank you. (If you give me all of the correct answers...
Chemistry
14.01.2021 08:31
What are some factors (natural or artificial) that could influence...
Chemistry
25.01.2021 23:35
Where on a typical human body, do we experience the greatest...
Chemistry
06.10.2021 06:14

New questions by subject

Subjects/you/study/ai school?...
English
13.08.2021 18:25
The cube of an integer is called a ?...
Mathematics
19.01.2020 22:43
Find the perimeter and area , Please help me on this will give...
Mathematics
07.12.2021 05:30
What is the awnser y= 4x-9...
Mathematics
19.07.2021 07:23
Triangle HIJ, with vertices H(-8,5), I(-4,3), J(-2,8), is drawn...
Mathematics
21.10.2020 01:10
Two-thirds a numberx plus 4 is 8....
Mathematics
30.11.2022 15:28
An air-filled solenoid has an inductance 36 mH. Find the emf...
Physics
04.04.2020 03:18
#
#
#
#
# #

We expand our knowledge with many expert answers