CHEM 209 Midterm 2
DATE ____________
NAME ___________________
NAvogadro = 6.02 1023
Activity Series of Metals
Li>K>Ba>Ca>Na>Mg>Al>Mn>Zn>Fe>Cd>Co>Ni>Sn>Pb>H2>Cu>Ag>Pt>Au
1.
Using the template below, give the electron configuration of Se in cell diagram
notations
3d
3p
4p
4s
3s
2s
2p
1s
2.
Name these compounds:
Na2SO3 ____________________
I2O5
____________________
Pb(NO3)2 _________________
3.
Write the chemical formulas of cadmium sulfide, lead(IV) oxide, silver nitrate,
calcium carbonate, dinitrogen pentoxide, nitrite ion, nitrate ion, nitride ion, iron(III)
hydroxide, potassium hydrogenphosphate
4.
Compile the Lewis electron-dot formulas for the following:
nitrite ion
selenium trioxide
5.
Identify polar molecular compound(s) out of the following:
(a)
SbCl5
(b)
SOCl2
(c)
SCl6
(d)
SnCl2
For sulfite ion, SO32- :
6.
Compile its Lewis electron-dot formula.
7.
Determine & sketch its electron configuration:
8.
Determine & sketch its molecular geometry:
For potassium pyrosulfate, K2S2O7
9.
Calculate its molar mass
10.
Determine its mass percent composition
%K =
%S =
%O =
11.
Determine the oxidation number of sulfur in it.
12.
How many moles of potassium pyrosulfate are there in 200.00 g of it?
13.
Determine the molecular formula of a compound containing 37.5 % C, 12.5 % H,
the rest being oxygen, if its estimated molar mass is about 60g/mol. C2H6O2
14.
Determine the mass percent of nitrogen in ammonium nitrate, NH4NO3
15.
How many moles of nitrogen are there in 39.0 g of calcium nitride?
16.
How many moles of ions are released in a solution when 1 mole of Na2SO4
dissolves in water?
17.
How many atoms are there in 3 moles of K2CO3?
18.
Finish (including balancing) the chemical equation for a reaction between
magnesium sulfate and barium chloride in aqueous solution. Indicate the physical state of
the products. Compile the ionic & net ionic equations for that reaction.
19.
Balance a chemical equation, such as:
BH3 + O2  B2O3 + H2O
20.
For the reaction in the previous problem determine which element(s) is (are)
oxidized and reduced.
21.
Finish (including balancing) the chemical equations for those reactions below that
are possible. If the reaction would not go, state so ( X).
Zn + H2SO4(aq) 
Cu + HCl(aq) 
Mg + CuCl2(aq) 
Cu + ZnSO4(aq) 
22.
Write the net ionic equation for the reaction between calcium chloride & silver
nitrate in an aqueous solution.
23.
Predict which reactions will go to completion & compile balanced chemical
equation for each of them, indicating the physical state of products. Write the net ionic
equations where appropriate.
(a) Cobalt(III) nitrate + sodium sulfide
(b) Magnesium chloride + sodium phoisphate
(c) Potassium chloride + sodium nitrate
(d) Sodium carbonate + hydrochloric acid
(e) Copper(II) hydroxide + hydrobromic acid
(g) Manganese(II) sulfate + sodium hydroxide
24.
Sulfur is completely oxidized with oxygen producing sulfur dioxide. Haw many
grams of sulfur are necessary to prepare 19.7 g of SO2?
25.
How many moles of barium sulfate will be produced when a solution containing
0.41 mol of barium chloride is mixed with a solution containing 0.29 mol of sodium
sulfate?
26.
In an experiment described in the previous problem, after isolating, washing,
filtering & drying the precipitate, its mass was measured as 61.32 g. What was the
percent yield of that operation?