Exam 2                 Chemistry 1A                  Name______________________

1  Balance the following molecular equations and write the net ionic equations where indicated. If no reaction occurs, write N.R.

a) C₂H₅OH_(l) + 3O₂(g) ---> 2CO_2(g) + 3H₂O_(g)

b) 3Zn_(s) + 2H₃PO₃(aq) ---> Zn₃(PO₄)_2(s)  +  3H_2(g)

b) Net Ionic:    3Zn_(s) + 2H₃PO_3(aq) ---> Zn₃(PO₃)_2(s)  +  3H_2(g)

c) 2HNO₃(aq) + Ni(OH)₂(s) --->  Ni(NO₃)_2(aq) + 2H₂O_(l)

c) Net Ionic:    2H⁺_(aq)  + Ni(OH)_2(s) --->  Ni²⁺_(aq) + 2H₂O_(l)

d) H₂SO₄(aq) + 2KHCO₃(aq) ---> K₂SO_4(aq) + 2CO_2(g) + 2H₂O_(l)

d) Net Ionic:      H⁺_(aq) + HSO₄^-_(aq) + 2HCO₃^-_(aq) ---> SO₄²_(aq)^- + 2CO_2(g) + 2H₂O_(l)

e) K₂O_(s) + 2HNO_3(aq) ---> 2KNO₃ +  H₂O_(l)

f) Na₂SO₄(aq) + AlCl₃(aq) ---> NR

f) Net Ionic:    2Na⁺_(aq) + SO₄^2-_(aq)  +  Al³⁺_(aq)  +  3Cl^-_(aq) ---> NR

g) BaCl₂(aq) + 2AgNO₃(aq) ---> Ba(NO₃)_2(aq) + 2 AgCl_(s)

g) Net Ionic:      Cl^-_(aq)  +  Ag⁺_(aq) --->  AgCl_(s)

h) 3HC₂H₃O_2(aq) + Al(OH)_3(s) ---> Al(C₂H₃O₂)_3(aq) + 3H₂O_(l)

h) Net Ionic:     3HC₂H₃O_2(aq) + Al(OH)_3(s) ---> Al³⁺_(aq) +3C₂H₃O₂^-_(aq) + 3H₂O_(l)

i) 3Ca_(s) + 2Fe(NO₃)₃(aq) ---> 3Ca(NO₃)_2(aq)+ 2Fe_(s)

i) Net Ionic:     3Ca_(s) + 2Fe³⁺_(aq) ---> 3Ca²⁺_(aq) + 2Fe

j) HCl_(aq) + NaC₂H₃O_{2(aq) --->} NaCl_(aq) + HC₂H₃O_2(aq)

j) Net Ionic:      H⁺_(aq)  +C₂H₃O₂^-_{(aq) --->}  HC₂H₃O_2(aq)

2 Give the formulas of the anhydrides for the following acids and bases.

a H₂SO₄         b Ba(OH)₂           c HNO₂        d H₂CO₃         e HClO₄
a SO₃              b BaO                 c N₂O₃         d CO₂             e Cl₂O₇

3 Completely explain the difference between a strong and weak acid in water.

Strong acids completely dissociate (100%) in water into hydronium and an anion. Weak acids only partially dissociate and give comparatively little hydronium ion in water.

4 Completely explain the difference between a strong and weak base in water.

Strong bases completely dissociate (100%) in water into hydroxide and a cation, that is, they are soluble hydroxides. Weak bases only partially dissociate or partially react with water and give comparatively little hydroxide ion in water.

5 Balance the following oxidation-reduction equations.

12HCl  + 4KMnO₄ + 5C₂H₅OH  ---> 4MnCl₂ + 5HC₂H₃O₂ + 4KCl  + 11H₂O
 
3Cu + 8HNO₃ --->  3Cu(NO₃)₂ + 2NO + 4H₂O

14H⁺  +  Cr₂O₇^-2 + 3Sn⁺²  --->  2Cr⁺³  +  3Sn⁺⁴ +  7H₂O
 
6.    Calculate the molarity of a solution made by adding 55.0 g of H₂SO₄ to 250 ml of water.

2.01M

7.      What volume of 3.00 M H₃PO₄ is needed to completely react with 50.0 ml of 1.500 M Na₂CO₃. First balance the equation.
16.8 mL 

8.      Consider 6.00 liters of CO₂ gas at 1.00 atm and 20.0°C . Note that each problem hereafter refers to this sample of gas and not to each other.
a) Find the volume of this gas at 150°C and 800 torr.
 8.23 L 

b) How many moles of gas are present?
  .2495 mole
 
c)    What mass of Na₂CO₃ was reacted with excess HCl to form this gas?
   26.4 g
d)    What volume of oxygen gas at 1.00 atm and 20.0°C is needed to react with excess carbon to form this gas?

  6.00 L
e)    What is the rms velocity of this gas at STP.

  393 m/s
f)    How many times faster does hydrogen effuse through a hole than CO₂ under the same conditions.
 4.67 times faster