Dave's ESL Cafe's Student Discussion Forums

[g-funk]

hey people i am new to this site and require some help with some uni style chem questions i missed the lecture so am having a bit of trouble getting consistant answers. can anyone help buy getting an answer to the following questions...


1)

redox balncing:
Which of the following represents a balanced, overall equation for the oxidation of iron (II) in acid solution?
Cr2O72-(aq) + Fe2+(aq) 2Cr3+(aq) + Fe3+(aq)

a. Cr2O72-(aq) + 6Fe2+(aq) + 14H+(aq) 2Cr3+(aq) + 6Fe3+(aq) + 7H2O(l)
b. Cr2O72-(aq) + 6Fe2+(aq) + 7H+(aq) 2Cr3+(aq) + 6Fe3+(aq) + 7H2O(l)
c. Cr2O72-(aq) + 6Fe2+(aq) + 14H+(aq) Cr3+(aq) + 6Fe3+(aq) + 7H2O(l)
d. Cr2O72-(aq) + Fe2+(aq) + 14H+(aq) 3/42Cr3+(aq) + 6Fe3+(aq) + 7H2O(l)


2)
What is the pH of a solution made by mixing 1600 mL of 0.05 M HNO3 and 400 mL of water?

a. -1.4
b. 1.4
c. -1.3
d. 2.0
e. 2.1


3)

3.0 L of 0.2 M K2CrO4 and 6.0 L of 0.4 M BaCl2 were mixed. Assuming that the barium chromate is insoluble the molarity of Ba2+ in the final solution is :

a. 1.8 M
b. 0.2 M
c. 0.6 M
d. 0.4 M
e. none of these


cheers guys any help would be great.

[summit]

1. A

[summit]

2. B
3. B