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1. In the laboratory, a student adds 44.6 mL of water to 10.8 mL of a 0.763 M pe

ID: 891234 • Letter: 1

Question

1. In the laboratory, a student adds 44.6 mL of water to 10.8 mL of a 0.763 M perchloric acid solution. What is the concentration of the diluted solution ? ______________ M

2. In the laboratory a student combines 24.3 mL of a 0.390 M copper(II) sulfate solution with 22.3 mL of a 0.302 Mpotassium sulfate solution.

What is the final concentration of sulfate anion ? ______________ M

3. Determine the oxidation state for each of the elements below.

The oxidation state of

sulfur

in

sulfite ion
SO32-

is _____

.

The oxidation state of

sulfur

in

sulfur solid
S8

is ________

.

The oxidation state of

carbon

in

oxalic acid
H2C2O4

is

______ .

The oxidation state of

...

sulfur

...

in

...

sulfite ion
SO32-

...

is _____

...

.

The oxidation state of

sulfur

in

sulfur solid
S8

is ________

.

The oxidation state of

carbon

in

oxalic acid
H2C2O4

is

______ .

Explanation / Answer

1) 44.6 mL of water to 10.8 mL of a 0.763 M perchloric acid solution. What is the concentration of the diluted solution ?

perchloric acid                                                H2o

M1=0.763 V1= 10.8    M2= ?    V2= 44.6 ml

                     M1V1=M2V2

                                                       M2=[M1V1 ]/V2

                                                  M2=[0.763X10.8 ] / [44.6]

                                           = 0.185 M

the concentration of the diluted solution is 0.185 M

2).

            Cuso4---------------->    cu+2          +       So-24

   n= [24.3x0.390]/1000           9.477x10-3        9.477x10-3

          K2SO4 ----------------->        2K+               +     SO-24

     n= [22.3 X0.302] / 1000            6.7346x10-3               6.7346x10-3

Final concentration of sulfate ion = [9.477x10-3 x24.3] +[ 6.7346x10-3x22.3] / [24.3+22.3]

                                                    =[230.29x10-3] +[ 150.18x10-3] / [46.6]

                                                    = [380.47x10-3] /46.6

  Final concentration of sulfate ion   = 8.1645x10-3

3)

The oxidation state of Sulphur in SO-23

      X+3(-2) = -2

        X-6=-2

       X=6-2

    The oxidation state of Sulphur in SO-23 is +4

The oxidation state of Sulphur in S8 Zero

The oxidation state of carbon in     H2C2O4

                                                            =2(1) + 2x +4(-2) =0

                                                            2x=6

                                                             x=+3

    The oxidation state of carbon in     H2C2O4 is +3