27. Dissolved dioxygen in water samples can be determined by the following equations: 2MnSO4(aq) + 4NaOH(aq) + O2(g) --> 2MnO2(s) + 2Na2SO4(aq) + 2H2O(l) 2MnO2(s) + 2H2SO4(aq) + 2NaI(aq) -->MnSO4(aq) + I2(aq) + Na2SO4(aq) + 2H2O(l) I2(aq) + 2Na2S2O3(aq) --> Na2S4O6(aq) + 2NaI(aq) A water sample from the local river was treated according to the first two equations above. Exactly 200.00 mL of this treated water required 8.32 mL of 0.0250 M Na2S2O3 to titrate to the endpoint. Calculate the concentration of dissolved oxygen in the water sample. A) 1.04 x 10-3M B) 2.08 x 10-4M C) 5.20 x 10-4M D) 8.67 x 10-7M E) 4.33 x 10-7M
(please see pictures attached for reference. I tried my best)
27. Dissolved dioxygen in water samples can be determined by the following equations:
2MnSO4(aq) + 4NaOH(aq) + O2(g) --> 2MnO2(s) + 2Na2SO4(aq) + 2H2O(l)
2MnO2(s) + 2H2SO4(aq) + 2NaI(aq) -->MnSO4(aq) + I2(aq) + Na2SO4(aq) + 2H2O(l)
I2(aq) + 2Na2S2O3(aq) --> Na2S4O6(aq) + 2NaI(aq)
A water sample from the local river was treated according to the first two equations above. Exactly 200.00 mL of
this treated water required 8.32 mL of 0.0250 M Na2S2O3 to titrate to the endpoint. Calculate the concentration of
dissolved oxygen in the water sample.
A) 1.04 x 10-3M
B) 2.08 x 10-4M
C) 5.20 x 10-4M
D) 8.67 x 10-7M
E) 4.33 x 10-7M
28) How many neutrons are needed to initiate the fission reaction shown?
23592 U + ? 10 n --> 13956 Ba +9436 Kr+ 310n
a) 0
b) 1
c) 2
d) 3
e) 5
20. Consider the substances H2O, KI, H2S, CH4. Which answer has the substances arranged in order of
DECREASING boiling point?
a) KI > H2O > CH4 > H2S
b) KI > CH4 > H2S > H2O
c) H2O > KI > H2S > CH4
d) KI > H2S > H2O > CH4
e) KI > H2O > H2S > CH4
Trending now
This is a popular solution!
Step by step
Solved in 3 steps
