Chemistry 330

Test

1.  True or False

A)  HNO3 is a polyprotic acid.

B)  Air is a solution.

C)  Reduction occurs when electrons are lost.

D)  Reducing agents are oxidized.

E)  An oxidation process must always be coupled with a reduction process.

F)  In the reaction NH3 + H2O → NH4+ + OH- water is a Brønsted base.

G)  NaHCO3 will react with bases to produce carbon dioxide.

H)  In H2O2 the oxidation number of the oxygen is -2.


I) In CaH2 the oxidation number for hydrogen is -1.

I)  Sodium chloride is an electrolyte.

2.  When aqueous solutions of sodium carbonate and calcium chloride are mixed together a precipitate forms.

a)  Write the complete balanced chemical reaction equation describing the chemical reaction.

b)  Write the ionic reaction equation for the above chemical reaction.

c)  Write the net ionic equation for the reaction.

3.  How many grams of MgSO4 are required to make a 250mL of a 1.25M solution?

4.  The concentration of a hydrochloric acid solution was determined by titration using a 0.26 M sodium hydroxide solution. It took 36.2mL of the NaOH solution to neutralize (faint pink endpoint) 25.00mL of the acid solution.

What is the concentration of the HCl solution?

5.  The diprotic acid, oxalic acid (H2C2O4) reacts with potassium permanganate as follows:

16H+ + 5C2O4-2 + 2MnO4- → 10CO2 + 2Mn+2 + 8H2O

How many milliliters of a 0.0100 M solution of potassium permanganate solution would be needed to react with 1.50g of oxalic acid?


BONUS!

How many milliliters of a 50% (50g solute/100g solution) hydrogen peroxide solution would be required to make 250.mL of a 0.500M solution? The density of 50% hydrogen peroxide is 1.196g/cm3.


Solubility Rules for Common Ionic Compounds in Water at 25ºC

(Helpful for Predicting Double Displacement Reactions)

Soluble Compounds / Exceptions
Compounds containing alkali metal ions (Li+, Na+, Rb+, Cs+) and the ammonium ion (NH4+)
Nitrates (NO3-), bicarbonates (HCO3-), and chlorates (ClO3-)
Halides (Cl-, Br-, I-) / Halides of Ag+, Hg22+, and Pb2+
Sulfates (SO42-) / Sulfates of Ag+, Ca2+, Sr2+, Ba2+, Hg22+, and Pb2+
Insoluble Compounds / Exceptions
Carbonates (CO32-), phosphates (PO43-), chromates (CrO42-), and sulfides (S2-) / Compounds containing alkali metal ions and the ammonium ion
Hydroxides (OH-) / Compounds containing alkali metal ions, the ammonium ion, and the Ba2+ ion
Activity Series of the Elements
(Helpful for Predicting Single Displacement Reactions)
Activity of metals / Activity of halogen nonmetals
Li / React with cold water and acids, replacing hydrogen. React with oxygen, forming oxides / F2
Rb / Cl2
K / Br2
Ba / I2
Sr
Ca
Na
Mg / React with steam (but not cold water) and acids, replacing hydrogen. React with oxygen, forming oxides
Al
Mn
Zn
Cr
Fe
Cd
Co / Do not react with water. React with acids, replacing hydrogen. React with oxygen, forming oxides.
Ni
Sn
Pb
H2 / React with oxygen, forming oxides.
Sb
Bi
Cu
Hg
Ag / Fairly unreactive, forming oxides only indirectly.
Pt
Au