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62 5. To what volume must each of the following be diluted to give the concentra

ID: 704907 • Letter: 6

Question

62 5. To what volume must each of the following be diluted to give the concentration called for? (300ml) a. 10.0ml of 6.00N HNOs to give 0.200N solution b. 9.00ml of concentrated H2SO, (18.0M) to give a 0.300M solution (540ml) 6. 24.60ml of 0.185N HNO3 is titrated with 27.35ml of KOH solution. What is the normality of the KOH? (0.166N) 7. The molar mass of phosphoric acid is 98.0 grams. What is its equivalent weight in each of the following reactions? a. H3PO4 + Al(OH)3 AIPo, + 3H20 b. HsPo, + NaOH-> NaH2PO4 + H2O c. H3PO4 + 2NaOH-+ Na2HPO4 + 2H2O (32.7g) (98.0g) (49.0g) (32.7g) (98.0g) e. H3POs+Ca(OH)2-Ca(H2POa)2+2H2O

Explanation / Answer

5.
a.    Initial                                 Final
     N1 = 6N                                 N2 = 0.2N
     V1 = 10ml                               V2 =
                  N1V1   = N2V2
                    V2   = N1V1/N2
                         = 6*10/0.2 = 300ml >>>>answer
b. Initial                        Final
   M1 = 18M                      M2   = 0.3M
   V1 = 9ml                      V2 =
           M1V1   = M2V2
              V2 = M1V1/M2
                  = 18*9/0.3 = 540ml >>>>answer
6.    HNO3(aq) + KOH(aq) ---------> KNO3(aq) + H2O(l)
   HNO3                      KOH
N1 = 0.185M               N2
V1 = 24.6ml               V2 = 27.35ml
     N1V1   = N2V2
       N2   = N1V1/v2
            = 0.185*24.6/27.35   = 0.166N >>>answer
7.
   a. H3Po4 + Al(OH)3 -----> AlPO4 + 3H2O
    Equivalent weight   = molar mass of acid/number of hydrogen atoms are replaced
                        = 98/3   = 32.7g
b. H3Po4 + NaOH ----------> NaH2Po4 + H2O
Equivalent weight   = molar mass of acid/number of hydrogen atoms are replaced
                    = 98/1   = 98g
c. H3Po4 + 2NaOH ---------> Na2HPO4 + 2H2O
Equivalent weight   = molar mass of acid/number of hydrogen atoms are replaced
                      = 98/2   = 49g
d.
H3Po4 + 3NaOH ---------> Na3PO4 + 2H2O
Equivalent weight   = molar mass of acid/number of hydrogen atoms are replaced
                      = 98/3   = 32.7g
e. H3PO4 + Ca(OH)2 -----------> Ca(H2Po4)2 +2H2O
Equivalent weight   = molar mass of acid/number of hydrogen atoms are replaced
                    = 98/1   = 98g