General Chemistry Answers

What is the E° _cell for the cell represented by the combination of the following half-reactions?

MnO₄^-(aq) + 8H⁺(aq) + 5e^- ↔ Mn⁺²(aq) + 4H₂O(l) E° = 1.51 V

VO₂⁺(aq) + 2H⁺(aq) + e^- ↔ VO⁺(aq) + H₂O(l) E° = 0.991 V

1. -0.52 V
2. 2.50 V
3. 0.52 V
4. -2.50 V

Two types of electrochemical cells which are based on thermodynamic principles can be described. Which of the following statements about these cells is correct?

a)The electrons in the external wire flow from cathode to anode in both cells.

b)Oxidation occurs at the cathode only in the voltaic cell.

c)The free energy change, ΔG, is negative for the electrolytic cell.

d)The cathode is positive in a voltaic cell but negative in an electrolytic cell.

Complete and balance the following redox equation. What is the coefficient of H₂S when the equation is balanced with the set of smallest whole numbers?

H₂S + MnO₄^- → Mn²⁺ + SO₄^2– (acidic solution)

1. 1
2. 2
3. 4
4. 5
5. None of the above.

Balance the following redox equation using the smallest integers possible and select the correct coefficient for the OH^-.

Zn(s) + H₂SO₃(aq) + OH^-(aq) + H₂0(l) → Zn(OH)₄^2-(aq) + S(s)

1. 2
2. 4
3. 6
4. 8

Which of the following solids would be considered an inactive electrode in an electrochemical cell?

a)zinc

b)graphite

c)copper

d)iron

Sodium thiosulfate, Na₂S₂O₃, is used as a ^"fixer^" in black and white photography. Identify the reducing agent in the reaction of thiosulfate with iodine.

2S₂O₃^2-(aq) + I₂(aq) → S₄O₆^2-(aq) + 2I^-(aq)

1. I₂(aq)
2. I^-(aq)
3. S₂O₃^2-(aq)
4. S₄O₆^2-(aq)

at the top of mount everest the force of gravity is less than at sea level. describe what would happen to your mass and to your weight if you traveled from sea level to the top of mount everest

Prepare 50ml of 0.3N Ba(OH)2 * 8 H2O

when methane gas is mixed with chlorine gas, hydrochloric acid is produced. the balanced equation is: CH4(g) + 2(Cl2)(g) ->4HCl(g) +CCl4(g) What mass of hydrochloric acid is produced if 1.25 g of CH4 reacts in excess of chlorine gas?

Sodium only has one naturally occuring isotope, Na23 , with a relative atomic mass of 22.9898 u. A synthetic, radioactive isotope of sodium, Na22 , is used in positron emission tomography. Na22 has a relative atomic mass of 21.9944 u. 

A 1.3476 g sample of sodium containing a mixture of Na23 and Na22 has an apparent "atomic mass" of 22.9501 u . Find the mass of Na22 contained in this sample.