PS 430 2007

1. A

2. A

3. B

4. C

5. D

6. D

7. 0.058*54 + 0.917*56 + 0.0217*57+ 0.0033%58 = AVERAGE MASS

= 59.8 units

8. Polonium has a valence of 6. It shares two electrons with two hydrogen atoms, each of which has a valence of 1.

H--Po--H

The molecular formula of this liquid is H₂Po. Note that Po is in oxygen’s family.

9. R_parallel = 4 W.

R_total = 4 W + 10 W + 10 W = 24 W

I = V/R = 12 V / 24 W = 0.5 A

V₂ = IR₂ = 0.5(4) = 2 V

10. V = IR

I = V/R = 120/ 240 = 0.5 A

VIt = mcDT

120(0.5)(43200 seconds) =20 000 g (4.19)(T_f-24)

T_f = 55 ^oC

11.

compound	Bond type	Compound type
K2Cr2O7	IONIC	SALT
C3H7OH	COVALENT	ALCOHOL
NaHCO3	IONIC	SALT
NCl3	COVALENT	COVALENT

12. Mg(OH)₂ OH^-

NaClO ClO^-

Al₂(SO₄)₃ SO₄^-2

Na₂B₄O₇ B₄O₇^-2

13. pH = 4

[H⁺] = 10^-pH = 10^-4 moles/L

[H⁺][OH^-] = 10^-14

[OH^-]= 10^-14/[H⁺]

= 10^-14/10^-4 = 10^-10 moles/L

14. n = CV

= 0.50 mole/L(0.250 L)

= 0.125 moles

0.125 moles (74 g/mole) = 9.3 g

15. 760 g(mole/190 g) = 4.0 moles TiCl₄

4.0 moles TiCl₄ ( 4 HCl/ TiCl₄) = 16 moles HCl

16 moles HCl (35.5 g/mole) = 568 g