Chem. 10

Test 2

October 18, 1999

Name__________________________________

Multiple Choice.  Choose the best answer.

1.        A compound is formed by combining the cation A³⁺ with an anion B^2-.  The formula of the hypothetical compound  formed is

a.  A₃B₂                           d.  2AB₃

            b. 3A₂B₃                         e.  A₃B₃

 c. A₂B₃

2.        Give the Stock name of the compound whose formula is FeCl₂

1. ferrous chloride
2. ferric chloride
3. iron chloride
4. iron(II)chloride
5. iron(III)chloride

3.        Give the classical name of the compound  SnO2.

1. tin oxide
2. tin  monoxide
3. stannic oxygen
4. stannous oxide
5. stannic oxide

4.        Which of  the following pairs of elements is most likely to form a covalent compound?

1. sodium and oxygen
2. hydrogen and chlorine
3. magnesium and bromine
4. potassium and sulfur
5. barium and iodine

5.        What is the formula of the compound calcium cyanide?

a.  Ca(CN)₂                     b.  Ca₃N₂                c.  Ca(CN)₂             d.  Ca₃N                  e.  CaN

6.        Name the compound whose formula is P₄S₇.

1. tetrapotassium heptasulfide
2. tetraphosphorus heptasulfide
3. heptaphosphorus tetrasulfide
4. tetraphosphorus heptasodium
5. none of the above

7.        Name the acid whose formula is H₂S.

1. sulfuric acid
2. sulfurous acid
3. hydrosulfuric acid
4. hydrosulfurous acid
5. none of the above

8.        What is the correct formula of the compound trisilicon tetranitride?

a.  Si₃N₄          b.  Si₃N                   c.  Ag₃N₄ d.  3Si₄N                e.  Si₃Ni₄

9.        Which of the following is not a sign that a chemical change has occurred?

1. a change in color
2. precipitation
3. evolution of a gas
4. release of heat
5. emission of light

10.     When the equation

C₂H_2(g)  +  O₂  ------->  C0₂   +   H₂O

         is correctly balanced, the sum of all the coefficients is

                a.  12       b.  11       c. 10         d.  13            e.  >13

11.     Refer to the equation below

HCl  +  Sb₂O₃   ------->    SbCl₃      +   H₂0

        When this equation is balanced with the lowest whole number coefficients, the sum of the coefficients

        is

                a.  10       b.  11       c.  12        d.  <10                    e.  >12

12-16.         Identify the type of chemical change illustrated in each of the following equations.  Use

A, for combustion,  B, for double  replacement, C, for single replacement, D, for combination,

and E, for decomposition.

12.  2PbO₂  ------->   2PbO   +   O₂

13.   Cu  +  2AgNO₃   ------>  Cu(NO₃)₂   +  2Ag

14.  SO₃  +   H₂0  --->   H₂SO₄

15.  CS₂   +   3O₂  ----->    CO₂  +    2SO₂

16.   BaCl₂   +  K₂CrO₄    ---->    BaCrO_4(s)    +   2KCl

17.     Nitroglycerine, C₃H₅(NO₃)₃, is used in the manufacture of dynamite as well as in treating some heart

disorders.  Determine its molar mass (g/mol).

a.  103.08        b.  199.08                c.  227.10                 d. 333.33                 e.  818.07

18.     How many Cu atoms are in 0.25 mol of Cu metal?

a.  0.25            b.  6.0 x 10²³           c.  4.5 x 10²³            d.  1.5 x 10²³           e.  none of these

19.     The chemical formula of the sugar glucose is C₆H₁₂O₆.  Determine the mass % of hydrogen in this compound.

a.  6.71                    b. 30.0                     c.  12.5                     d.  8.10                    e.  3.35

20.     A 20.0 gram sample of a hydrocarbon (a compound which contains only hydrogen and carbon)is found to contain 17.13 grams of carbon.  Which of the following could this compound NOT be?

a.  C₄H₈                           b.C₃H₆                    c.  C₆H₁₂                  d.  C₉H₁₈                 e.  C₄H₁₀

                                                                                                                                                                                                                                                                                                                R x 3 = 60

Name_________________________________________

Wherever there is a reaction, write the products and balance the equation.  Otherwise, write No Reaction, NR.

1.        CaCO₃  (heated)  -------->

2.  SbCl₃  +   KOH   ------->

3.  HCl   +    Au    --------->

4.  Mg(OH)₂    +   HNO₃   -------->

5.  Cl₂   +   KF   -------->

6.  Al  +   CuS0₄  -------->

7.  Pb  +   Ca(NO₃)_{2 (aq)}   ------->

8.   Zn   +   HCl_(aq)   --------->

9.        CaCl₂  +  Na₂CO₃------->

10.  K₂SO_{3 (aq)}    +     HCl_(aq) ------>

                                                                                                                No. R x 3 = 30 points

Problems

A clear, logical, stepwise solution with units must accompany each answer.  Answers only, without a solution, will not be graded.

1.        A 0.500 gram sample of citric acid is found to contain 0.1875 grams of carbon, 0.0210 grams of hydrogen, the reaminder oxygen.  what is the empirical formula of citric acid?

2.         Consider the reaction

        2C₄H₁₀  +  13O₂  ----->  8CO₂    +   10H₂O

a.        How many moles of  CO₂ and how many moles of H₂O are theoretically obtainable from the

complete combustion of 6.50 moles of C₄H₁₀?

b.       How many grams of  C₄H₁₀ and how many grams of O₂ are needed to produce  150.0 grams of                                CO₂?

c.         If 150.0 grams each of C₄H₁₀ and O₂ are brought together under the appropriate conditions,

what is the theoretical yield of CO₂?