Unit+4+Test+Questions

Post possible questions for test on friday here. :]

1. During the process of photosynthesis: 6 CO2 (g) + 6 H2O(aq) à  C6H12O6(aq) + 6 O2(g) a) carbon dioxide is oxidized b) hydrogen in water is reduced c) oxygen in carbondioxide and/or water is oxidized - answer d) oxygen in glucose is oxidized e) carbon in glucose is oxidized

2. All galvanic and electolytic cells require: a) an external power supply b) a voltmeter c) one electrode and two electrolytes d) two electrodes and one electrolyte - answer e) a porous barrier

3. How long does it take to produce 4.50g of scandium metal in the electrolysis of molten scandium chloride using a current of 8.5 A: a) 57 min - answer b) 19 min c) 6.3 min d) 1.1 min e) 0.54 min

4. When balancing a redox reaction in a basic solution, one must: a) Add H ions to both sides of the reaction b) Add OH ions to both sides of the reaction - answer c) Add water to both sides of the reaction d) Add H to one of the reaction e) Add OH to one side of the reaction

5. Select the statement which is correct. a) Oxidation is the loss of electrons and a rise in oxidation number - answer b) Reduction is the gain of electrons and a rise oxidation number c) Oxidation is the gain of electrons and a lowered oxidation number d) Reduction is the loss of electrons and a lowered oxidation number

6. Whose experiments with a dead frog led to incorrect conclusions? a) Volta b) Daniell c) Farraday d) Galvani - answer e) Nernst

7. Who was credited with the invention of the battery? a) Volta - answer b) Daniell c) Farraday d) Galvani e) Nernst

8. What does a lower electrode potential (E naught) mean about a chemical? a) it is a stronger reducing agent b) it is a stronger oxidizing agent c) it will be reduced when reacted with a chemical of higher electrode potential d) it will be oxidized when reacted with a chemical of a higher electrode potential e) at least two of statements are true - answer (a and d are both true)

9. Will a Galvanic cell created with Zn and Cr react spontaneously? (yes because Zn is a strong oxidixing agent and Cr is a strong reducing agent and the cell's potential (E.naught) is more than 0)

10. What is the oxidation number oh hydrogen(excluding hydrides and Hydrogen Peroxide)? a) -1 b) +1 <--- Correct Answer c) -2 d) +2

11. What is the oxidation number of oxygen? a) -1 b) +1 c) +2 d) -2 <Correct Answer

12. What is the oxidation number of the Carbon on the reactants side in the following equation? CH4+2O2 = CO2 + 2H2O

a) +4 <--- Wrong Answer b) -4 <--- Right Answer c) +1 d) -1

Isn't q.12 (-4)? H+ has an oxidation number of (+1) and since there are 4, the charge is (+4). Since the overall charge is (0), then Carbon has to be (-4) right? On the product side of the equation (+4) would be right though.

13. In an electrolytic cell which of the following is the negative electrode? a) anode b) cathode <--- Correct Answer c) none of the above d) circumlocution