Question

1. What percentage (%) is 1.5 M NaOH?ans: 6%

2. If you add 10g of NaOH to 500 ml, what is the concentration, in percent, of the solution? ans: 2% NaCl solution

3. If you add 10g of NaCl to make a 3 M solution, what is the total volume? mw=58.44 ans: 57 ml NaCl solution

4. Given 30% NaOH solution, how man mL's solution would you use to prepare 300 ml of 10% solution? ans: 100 ml of NaOH

Answer 1

answer=

1. What percentage (%) is 1.5 M NaOH

1 M NaOH means 40 gms NaOH --------1000 ml --------1M

1.5 M NaOH ? -------------1000 ml---------1.5M

=40X1.5

=60 gms

60gms for 1000 ml

6 gms i.e.6% for 100 ml

ans: 6%

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2. If you add 10g of NaOH to 500 ml, what is the concentration, in percent, of the solution?

40 gms NaOH --------1000 ml --------1M

20 gms ------------1000ml -------------0.5 M

20gms -----------500ml---------?M

=

ans: 2% NaCl solution

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3. If you add 10g of NaCl to make a 3 M solution, what is the total volume? mw=58.44

58.44 gms of NaCl --------- 1000 ml D.water-----------1M

?gms of NaCl ------------1000 ml------------3M

=58.44 X 3

=175.32 gm for 1000 ml

175.32 gms of NaCl--------1000 ml

10 gms ------------------------? ml

= 1000X 10 /175.32

=57.03 ml

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4. Given 30% NaOH solution, how man mL's solution would you use to prepare 300 ml of 10% solution? ans: 100 ml of NaOH

C1= start concentration= 30%

V1= ?

C2 =final conc.= 10 %

V2= final volume= 300ml

C1V1=C2V2

V1 = C2V2/C1

= 10 X 300 /30

=100 ml