Answers to 416 June 06

1. B

2. B

3. B

4. B

5. C

6. C

7. D

8. B

9. D

10. A

11. B

12. C

13. B

14. A

15. A

16. C

17. C

18. D

19. A

20. From the list of “capacity to”GAIN ELECTRONS” list, we realize that the higher the material is on the list, the more likely it is to be charged negative.When glass is rubbed with silk, the silk will gain electrons from the glass. Glass will be positive. Applying the same reasoning to the second part, we realize that vinyl will be negative. The two objects shown will therefore attract.

21. 1=Ni because the density matches and because it is ferromagnetic. 2= Ti because it conducts and because its density matches.

22. 0.010kW(7*52)h ($0.06/kWh) = $0.21.

23. Q = mcDT

25140 J= 200g(4.19J/g^oC)(x-17) ^oC

x = 47 ^oC

24. C₁V₁ = C₂V₂

100g/L(0.050 L) = 25g/LV₂

2 = 0.200 L = 200. ml

25. methane: 64 + 16 - 36 = 44 g of carbon dioxide

Propane; 11 + 40 – 18 = 33 g

Propane produces less( comparison, though is meaningless because it’s neither based on equal moles nor on equal mass)