## Conversions

Foothill College Chem25 Exam2A Nov. 18, 2009 Name: Constants/Conversions atm = 101.325 J 1 J = 107 erg RH = 2.18 x 10-18 J 1 eV = 96.45 kJ/mol 1atm...
Foothill College Chem25 Exam2A

Nov. 18, 2009 Name:

Constants/Conversions

atm = 101.325 J 1 J = 107 erg RH = 2.18 x 10-18 J 1 eV = 96.45 kJ/mol 1atm = 760 torr = 760 mm-Hg = 1.01325 x105 Pa Equations E = hv C= vλ K = °C + 273.15 ΔT = kfm En = (-RH)

π = MRT λ = h/mv ΔE = q + w Ecell = Ered + Eox q = CΔT = n CΔT = m s ΔT

E = hc/λ EΨ = HΨ ΔT= kbm

1 n2

Specific Heat =

R1/R2 = (M1/M2)-1/2 Ln A = ln A0 -kt KP = KC (RT)Δn F = 96,485 Coul/mol pH = pKa + log(

[base] ) [acid]

C=3.00 x 108 m/s e =1.602 x 10-19 Coul 1 amu= 1.66054 x 10-24 g NA = 6.02214 x 1023 h = 6.626 x 10-34 JS R = 8.3145 J/K°mol = 0.082058 L atm/ K°mol k = 1.38066 x 1023 J/K° 1 Cal = 4.184 J 1L

q m ⋅ ΔT

ln (

ΔH Vap P1 )=P2 R

⎛1 1 ⎞ ⋅ ⎜⎜ − ⎟⎟ ⎝ T1 T2 ⎠

E ∝ (Q+ Q)/d t1/2 = 0.693/k KaKb = Kw = 1 x 10-14 Cu2+ + 2e- → Cu(S)

nλ = 2d⋅sinθ ΔG = ΔH -TΔS k = A⋅exp(-Ea/RT) 1/A = 1/A0 -kt E° = + 0.337

ΔG = ΔG° =RT⋅ ln (Q)

E = E° -

ΔS°rxn = ΣnΔSf°(products) - ΣmΔSf°(reactants) ΔH°rxn = ΣnΔH°f(product)-ΣnΔH°(reactant)

2.303 ⋅ RT ⋅log (Q) nF

ΔG = -nFE P1 = χ1PTotal

1A

8A

1

1 2 3 4 5 6 7

2

H

1.008 2A 3 4

Li

Be

Na

Mg

K

Ca

Rb

3A 5

6.941 9.012 11 12

4A 6

5A 7

6A 8

He

7A

4.003 10

9

B

C

N

O

F

Ne

Al

Si

P

S

Cl

Ar

10.81 12.01 14.01 16.00 19.00 20.18 13 14 15 16 17 18

22.99 24.31 3B 19 20 21

4B 22

5B 23

6B 24

7B 25

Sc

Ti

V

Cr

Mn

Sr

Y

Zr

Nb

Mo

Tc

Cs

Ba

La

Hf

Ta

W

Re

Fr

Ra

Ac

Rf

Ha

Sg

Ns

26

8B 27

28

1B 29

2B 30

26.98 28.09 30.97 32.07 35.45 39.95 31 32 33 34 35 36

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Hs

Mt

39.10 40.08 44.96 47.90 50.94 52.00 54.94 55.85 58.93 58.70 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 85.47 87.62 88.91 91.22 92.91 95.94 (98) 55 56 57 72 73 74 75

101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 76 77 78 79 80 81 82 83 84 85 86

132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 (209) (210) 87 88 89 104 105 106 107 108 109 110 111 (223) (226)

(227) (261) (262) (266) (262) 58

6 7

59

60

61

Ce

Pr

Nd

Pm

Th

Pa

U

Np

Rn

(222)

(265) (266) 62

63

64

65

66

Sm

Eu

Gd

Tb

Dy

Pu

Am

Cm

Bk

Cf

67

68

69

70

71

Ho

Er

Tm

Yb

Lu

Es

Fm

Md

No

Lw

140.1 140.9 144.2 (145) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 91 92 93 94 95 96 97 98 99 100 101 102 103 232.0 (231) 238.0 (244)

(242) (243) (247) (247) (251)

(252) (257) (258) (259) (260)

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Foothill College Chem25 Exam2A

Nov. 18, 2009 Name: molecule CH4(g) HCl(g) CHCl3(l) HF(g) CH3OH(l) CO(g) HNO3(l) CO2(g) H2O(g) H2O(l)

ΔHf˚ -74.8 -92.3 -131.8 -268.6 -238.6 -110.5 -173.2 -393.5 -241.8 -285.8

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Foothill College Chem25 Exam2A

Nov. 18, 2009 Name:

MULTIPLE CHOICE QUESTIONS (60) 0. Your Section number is A. 01 (Monday Lab) B. 02 (Wednesday Lab) 1. Which statement about boiling point is FALSE? A. The boiling point is higher for compounds with strong intermolecular forces. B. The boiling point is higher for compounds with a high viscosity. C. The boiling point of a compound is an absolute constant. D. The boiling point of a compound is higher for nonvolatile compounds. 2.

Increasing the intermolecular forces of a liquid will do which of the following? A. increase the viscosity B. decrease the evaporation rate C. decrease the vapor pressure D. all of the above

3. The rate of vaporization of a liquid can be increased by 1. increasing the surface area 2. increasing the temperature 3. decreasing the strength of the intermolecular forces A. 1 only B. 2 only C. 3 only D. 1 and 2 only 4. What happens as you start to add heat to a solid substance? A. Thermal energy causes the components of the solid to vibrate faster in their stationary position. B. When the melting point is reached, the thermal energy is sufficient to overcome intermolecular forces holding the components stationary. C. Heating of the now formed liquid results in increasing the liquid temperature. D. all of the above 5. Which statement is true in describing what occurs when a solid melts to a liquid? A. The process is endothermic and the heat of fusion is positive. B. The process is endothermic and the heat of fusion is negative. C. The process is exothermic and the heat of fusion is positive. D. The process is exothermic and the heat of fusion is negative. 6. Which noble gas has the highest boiling point? A. Ne B. Ar C. Kr D. Xe 7. Substance A is a molecular compound that dissolves in gasoline but not in water. The molecules of A are very likely: A. metallic. B. nonmetallic. C. polar. D. nonpolar.

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Foothill College Chem25 Exam2A

Nov. 18, 2009 Name:

8. The primary cause of increasing greenhouse gases is: A. the burning of vast amounts of rain forests. B. the production of CO2 by respiration. C. the increased use of natural gas, petroleum and coal. D. the release of CO2 by decreasing solubility in the ocean. 9. How many grams of water are made from the reaction of 4.0 grams of hydrogen gas? Given the reaction: 2H 2 + O 2 → 2H 2 O A. 18 B. 72 C. 36 D. 4.5 10. What is the limiting reactant for the following reaction given we have 2.6 moles of HCl and 1.4 moles of Ca(OH) 2? 2HCl + Ca(OH) 2 → 2H 2 O + CaCl2 A. Ca(OH)2 B. HCl C. H2O D. CaCl2 11. A sample of 8.5 g NH3 on oxidation produces 4.5 g of NO. Calculate the percent yield. A. B. C. D.

15 % 30% 60% 70%

12. What type of a reaction occurs when a potassium nitrate solution is mixed with a barium acetate solution? A. precipitation B. acid-base neutralization C. gas evolution D. no reaction 13. Given that 4 NH3 + 5 O2 → ? NO + 6 H2O, when 4.50 mol of H2O are formed, the amount of NO formed is A. 1.50 mol B. 3.00 mol C. 4.50 mol D. 6.75 mol 14. What is the gas produced when hydrochloric acid is reacted with ammonium carbonate? A. ammonia B. chlorine C. hydrogen D. carbon dioxide

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Foothill College Chem25 Exam2A 15. Considering the following reaction:

Nov. 18, 2009 Name: Pb(NO3 ) 2 ( aq ) + 2KI ( aq ) → PbI 2 ( s ) + 2KNO3 ( aq )

Which

ion(s) would be spectator ions? A. Pb2+, NO3B. K+, NO3C. K+, ID. Pb2+, K+ 16. A precipitate is expected to be formed when an aqueous solution of sodium sulfate is added to an aqueous solution of A. iron(III) chloride B. potassium chloride C. magnesium chloride D. barium chloride 17. When elements combine to form compounds, A. their properties are an average of all elements in the compound. B. their properties change completely. C. their properties do not change. D. their properties are completely random. 18. Which of the following compounds have the smallest formula mass? A. CO2 B. NO2 C. SiO2 D. H2O 19. You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the largest number of moles? A. Na B. C C. Pb D. Ne 20. Which of the following molecules contain 9.02 × 1023 atoms? A. 4.00 g H2 B. 9.00 g H2O C. 28.0 g N2 D. 32.0 g O2 SHORT ANSWER (20 pts) 1. Definition. (5 pts) A. Normal boiling point B. Dispersion forces C. Oxidation-reduction reactions D. Spectator ions E. Empirical 2. Nomenclatures A. Mgnesium phosphate B. Barium nitrite C. Fe3(PO4)2

D. SF5 E. HBrO

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Foothill College Chem25 Exam2A

Nov. 18, 2009 Name:

3. How many kilojoules of heat are needed to completely vaporize 42.8grams of C 4 H 10 O at its boiling point? (ΔHvap = a kJ/mol on the white board) [(42.8 g)/(74.12 g/mol)] x (a kJ/mol) = 0.577a kJ 4. Evidences of a chemical reaction occur. LONG ANSWER （10 pts each） 1. What is the limiting reactant, theoretical yield, and percent yield for the following reaction given we have 557.899 g of Ca(NO3)2, 611.236 of Li3PO4 and 351.543 g of calcium phosphate produced? (you must write a balanced chemical equation)

3Ca(NO3 ) 2 + 2Li3PO 4 → 6LiNO3 + Ca 3 (PO 4 ) 2 3Ca(NO3)2 + 2Li3PO4 → 6LiNO3 + MM 164.088 115.79 68.948 mass 557.899 611.236 mole 3.400 1.5 pts 5.2788 1.5 pts mole/coef. 1.133 1.5 pts 2.639 1.5 pts LR 1 pt 1 pt 1.5 pts AY= 351.543 PY= (AY/TY)x100% = 100.00

1.5 pts Ca3(PO4)2 1.5 pts 310.188

1.133 1.5 pts 351.546 1.5 pts TY

2. A compound contains 13.58 g of carbon, 1.76 g of hydrogen and 13.45 g of oxygen. mass of 180.15 g/mol. What is its molecular formula?

Mass C H O Molar mass 180.15 Formula weight

13.58 1.76 13.45 102.088

mole mole ratio n 1.1307 1.35 3 1.7460 2.08 3 0.8406 1.00 3 1 pt 1 pt n= 1 pt

It has a molar

E. F. 4 6 3 1 pts

M. F. C8 H12 O6 1 pt 2 1 pt

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