Chem 2045

 Discussion session

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 Work sheet 15: "Something old, Something new"

1) One kilogram = _____ milligrams.

a) 1 x 10-6
b) 1 x 103
c) 1 x 104
d) 1 x 106

2) Which species has 29 neutrons, 26 protons and 23 electrons?

a) 55-Cu+6
b) 55-Fe+3
c) 55-Fe+6
d) 26-Fe+3

3) What is the correct name for the compound Fe2(CO3)3?

a) Iron carbonate
b) Iron (II) carbonate
c) Iron (III) carbonate
d) Triiron dicarbonate

4) How many grams of nitric acid can be prepared from the reaction of 69.0 g of nitrogen dioxide with 36.0 g of water?

3NO2 + H2O 2HNO3 + NO

a) 63.0 g
b) 84.0 g
c) 116 g
d) 252 g

5) Calculate the weight percent of carbon in H2CO3.

a) 3.2 %
b) 19.4 %
c) 45.6 %
d) 77.1 %

6) What is the percent yeild of CO2 if the reaction of 10.0 g of CO with excess O2 produces 12.8 g of CO2?

2CO(g) + O2(g) 2CO2(g)

a) 76.4 %
b) 78.1 %
c) 81.5 %
d) 84.4 %

7) Serotonin is a compound that conducts nerve impulsees in the brain and muscle. What is the empirical formula for Serotonin if it contains 68.2% C, 6.86% H, 15.9% N and 9.08% O?

a) C8H12N2O
b) C11H12N3O
c) C11H10N2O
d) C10H12N2O

8) What are the spectator ions in: Ba(NO3)2 (aq) + Na2SO4 (aq) BaSO4(s) + 2NaNO3 (aq)

a) Ba2+ and SO4 2-
b) Ba2+ and NO3-
c) Na+ and NO3-
d) Na+ and SO42-

9) Which of the following reactions is a oxidation-reduction (Redox) process?

a) H2O(l) + SO3 (g) H2SO4 (aq)
b) 2HCl(aq) + Mg(s) H2
(g) + MgCl2 (aq)
c) H2CO3
(aq) H2O(l) + CO2( g)
d) Ba(NO3)2
(aq) + Na2SO4 (aq) BaSO4 (s) + 2NaNO3 (aq)

10) An aqueous solution of ethanol (400 mL) was diluted to 4.00 L. The final concentration was 0.0400 M. What was the original concentration of the solution?

a) 0.0400 M
b) 0.400 M
c) 1.00 M
d) 4.00 M

11) E is always negative when a system _____

a) absorbs heat and does work.
b) gives off heat and does work.
c) absorbs heat and has work done on it.
d) gives off heat and has work done on it.

12) The value of H for the reaction below is -72 kJ. How many kJ of heat will be evolved when 1.0 mol of HBr is formed in this reaction?

H2(g) + Br2(g) 2HBr(g)

a) 144
b) 72
c) 36
d) -72

13) Calculate the frequency of light having a wavelength of 4.50 x 10-6 cm.

the speed of light = (wavelength) x (frequency)
the speed of light, c = 3.00 x 108 m/s

a) 6.67 x 1014 /s
b) 6.67 x 1013 /s
c) 6.67 x 1015 /s
d) 6.67 x 1017 /s

14) Which of the following does not apply to covalent bonds?

a) they can be polar or non-polar
b) the two elements in the bond are usually both non-metals
c) they are described by a "sea if electrons" model
d) they are the result of sharing of electrons between two bonded atoms

15) Which of the following compounds is most likely a radical?

a) CN-
b) O3
c) NO
d) BeF2

16) Which of the following molecules is polar?

a) SO42-
b) CH4
c) CCl4
d) SF4

17) Based on VSEPR theory, what is the electron domain geometry of TeF5- ?

a) trigonal planar
b) tetrahedral
c) trigonal bipyramidal
d) octahedral

18) Which of the following molecules would you predict to have the smallest bond angles?

a) SCl2
b) BF3
c) ClF3
d) NH3

19) According to valence bond (VB) theory, what is the hybridizaion of P in PCl5?

a) sp2
b) sp3
c) sp3d
d) sp3d2

20) How many sigma bonds and how many pi bonds does ethene, C2H4 have?

a) 4 sigma and 1 pi
b) 4 sigma and 2 pi
c) 5 sigma and 1 pi
d) alpha delta pi