Multiple Choice (3 Pts. Each)

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CHEM 10050Exam #2Name ______

Fall 1995Soc. Sec.# ______

Multiple Choice (3 pts. each)

____1) How many moles of K3PO4 are 21.2 g K3PO4?

a) 1.00b) 0.100c) 0.158d) 0.129

____2) The correct formula for potassium permanganate is:

a) K2MnO4b) K2Cr2O7c) KMnO4d) KCr2O7

____3) 9.0 g of water contains:

a) 3.0 x 1023 moleculesb) 3.0 x 1023 atoms

c) 6.022 x 1023 moleculesd) 6.022 x 1023 atoms

____4) The sulfur atom in the ion SOhas an oxidation number of:

a) -2b) -4c) +2d) +4

____5) The following reaction is a ______reaction: CaO + H2O  Ca(OH)2.

a) combinationb) decompositionc) single displacementd) combustion

____6) The oxidation number of the nitrogen atom in potassium nitrite is:

a) +3b) +4c) +5d) +6

____7) The energy required to remove and electron from an atom is called:

a) electronegativityb) ionization energyc) electron affinityd) polarity

____8) The oxygen difluoride (OF2) molecule is:

a) tetrahedral b) non-polarc) electronegatived) polar

____9) The formula for copper (II) sulfate is:

a) Cu(SO4)2b) Cu2SO4c) Cu3SO4d) CuSO4

____10) The reaction between an acid and a base produces:

a) carbon dioxide and saltb) carbon monoxide and water

c) water and saltd) carbon dioxide and water

____11) In which compound does nitrogen have an oxidation state of +5?

a) KNO2b) Ba(NO3)2c) N2H4d) NH3

____12) Oxygen in most of its compounds has an oxidation number of:

a) +1b) +2c) -1d) -2

____13) During the formation of an ionic bond, the atom which transfers its valence electron(s) to the other atom is the atom with the:

a) higher electronegativityb) lower electronegativity

c) higher ionization energyd) no correct answer given

____14) How many grams of gold (Au) are in 0.275 mol Au?

a) 0.542 gb) 5.42 gc) 54.2 gd) 542. g

____15) The correct formula for aluminum hydroxide is:

a) AlOHb) Al2(OH)3c) Al(OH)3d) Al3OH

____16) The attractive force that an element has for electrons shared in a covalent bond is called:

a) electronegativityb) ionization energyc) electron affinityd) polarity

____17) The bond in LiBr is:

a) polar covalentb) interestingc) ionicd) non-polar covalent

____18) Given the following unbalanced equation: H2 + O2  H2O

How many moles of oxygen is required to produce 3.6 g of H2O?

a) 0.100 molb) 1.00 molc) 10.0 mold) 100 mol

____19) A molecule that is electrically unsymmetrical and is oppositely charged at two points within the molecule is called:

a) a dipoleb) impossiblec) ionicd) covalent

____20) The percentage composition for the molecule C7H8O:

a) 91.30 % C, 6.63 % H, 2.07 % Ob) 67.74% C, 6.45 % H, 25.81 % O

c) 77.75 % C, 7.46 % H, 14.8 % Od) 41.39 % C, 3.47 % H, 35.13 % O

Solve the following problems showing all work. Remember to use proper units, significant figures and rounding.

1) Balance the following equations and write total ionic and net ionic equations for each. Circle the spectator ions in the total ionic equation (8 pts.)

a) HNO3(aq) + Na2CO3(aq)  H2O(l) + CO2(g) + NaNO3(aq)

b) Pb(NO3)2(aq) + K2Cr2O7(aq) PbCr2O7(s) + KNO3(aq)

2) Given the following unbalance equation, CO + H2  CH3OH, complete the following

(20 pts.):

a) Write the balance equation

b) How many milliliters of methyl alcohol (CH3OH) would be produced from 2.50 g of hydrogen gas (dCH3OH = 0.792 g/mL)?

c) If 15.0 mL of CH3OH is actually collected by the person doing this reaction, what is the percentage yield?

d) What class of reaction does this represent?

e) Is this a redox reaction? If it is, indicate which reactant is the oxidizing agent and which reactant is the reducing agent.

4) Draw Lewis Structures and predict the molecular geometry’s for the following (12 pts.):

a) SiBr4

b) SeO2

c) N

d) Circle the polar molecule above.