Islamic University of Gaza - Faculty of Science - Chemistry Department – CHEM1301 - Mid Exam I
18/3/2012 Time 60 minutes Instructor: ……………………….
Student Name: ……………………. Student I.D: ……………………..
======
Multiple Choice: Choose the correct answer after Showing Work
1. The chemical formula for copper(II)perchlorate is:
a) CuClO4 / b) CuClO3 / c) Cu(ClO4)2 / d) Cu(ClO3)22. How many phosphorus atoms are there in 15 g of H3PO4 (M.wt.= 98)? (Avogadro΄s No.=6.022×1023)
(a) 1.5x1022 / (b) 2.9x1023 / (c) 9.2x1022 / (d) 2.8x10243. A 1.04 g of an organic compound containing only C, H and O was burned to produce 2.062 g CO2 and 0.846 g H2O. What is the empirical formula of the compound? (At.wt: C = 12, O = 16, H = 1).
a) CH2O / b) C2H4O / c) C2HO2 / d) C2H4O4. Which of the following statements is true about the compounds CO2; KCl; KNO3; N2O
2
a) CO2 is the only molecular.
b) CO2 and N2O are the only molecular.
c) KCl, KNO3, and N2O are the only ionic.
d) CO2, KNO3, and N2O are the only molecular
2
e) KCl is the only ionic.
2
5. Which one of the following is named correctly?
2
a) Ca(HS)2, calcium sulfide
b) HBrO2, bromic acid
c) AlN, aluminum nitride
d) FeO, iron(III) oxide
e) NH4+, ammonia
2
6. If 4.0 moles of Li and 2.0 moles of O2 are used in the reaction 4Li + O2 à 2Li2O, then the limiting reactant is ______and the theoretical yield of Li2O is ______g.
2
a. 1.2 × 102
b. 9.0 × 101
c. 6.0 × 101
d. 3.0 × 101
2
7. For the reaction: 4Al(s) + 3O2(g) à 2Al2O3(s) , when 4.6 g Al was reacted with excess oxygen; 6.8 g of product was obtained. What was the percent yield of the reaction?
(At Wt: Al =27; O=16)
2
a. 74 %
b. 78 %
c. 68 %
d. 134 %
2
8. The element X consists of 5 isotopes with masses 63.929, 65.926, 66.927, 67.925, and 69.925 amu and relative abundances of 48.89, 27.81, 4.110, 18.57, and 0.62 percent, respectively. The average atomic mass of X is:
3
a) 63.93 amu
b) 66.93 amu
c) 65.387 amu
d) 65.927 amu
e) 65.39 amu
3
9. Which reaction will not produce a precipitate from aqueous solution?
3
a) AgNO3 + KI
b) FeSO4 + Ba(OH)2
c) Pb(NO3)2 + Na2CO3
d) ZnCl2 + (NH4)2S
e) NaBr + Al2(SO4)3
3
10. Which is NOT an oxidation-reduction reaction?
3
a. CaBr2(aq) + H2SO4(aq) CaSO4(s) + 2HBr(g)
b. 2Na(s) + 2 H2O(l) 2NaOH(aq) + H2(g)
c. 2H2(g) + O2(g) 2H2O(g)
d. 2Al(s) + 3H2SO4(aq) Al2(SO4)3(aq) + 3H2(g)
3
11. The correct net ionic equation for the reaction between solutions of Pb(NO3)2 and NH4Cl is?
a. Pb(NO3)2(aq) + 2NH4Cl(aq) NH4NO3(aq) + PbCl2(s)
b. Pb2+(aq) + 2Cl─(aq) PbCl2(s)
c. Pb2+(aq) + 2NO3─(aq) + 2NH4+(aq) + 2Cl─(aq) 2NH4+(aq) + 2NO3─(aq) + PbCl2(s)
d. NH4+(aq) + NO3─(aq) 2NH4NO3
12. A gas is compressed in a cylinder by a constant pressure of 10 atm from a volume of 20 L to 2.0 L. Calculate the work done on the system. (1 atm L = 101.3 J)
a) 1.01 104 J b) -180 J c) 1.81 104 J d) - 1.81 104 J e) 180 J
13. From the following enthalpies of reaction,
H2(g) + F2(g) à 2HF(g) DH = −537 kJ
C(s) + 2F2(g) à CF4(g) DH = − 680. kJ
2C(s) + 2H2(g) à C2H4(g) DH = +52.3 kJ
Calculate DH for the reaction C2H4(g) + 6F2(g) à 2CF4(g) + 4HF(g)
3
a) −1165 kJ
b) +234 kJ
c) −2486 kJ
d) −1269 kJ
e) −2382 kJ
3
14. For the reaction: Pb2+(aq) + 2Cl−(aq) à PbCl2(s) DH = −22.53 kJ/mol
Calculate DH when 0.230 mol of PbCl2(s) is dissolved in water.
3
a) 5.18 kJ
b) 22.5 kJ
c) −5.18 kJ
d) −22.5 kJ
3
15. What is the final temperature of 325 g of water at 4.2oC after absorbing 12.28 kJ? specific heat of water = 4.184 J/g·oC.
a. 4.21oC b. 4.8oC c. 9.0oC d. 13.2oC
3