Show all calculations in order to receive full credit. Avogadro’s Number = 6.02 x 10 ²³
 

1. Determine the % composition by mass of N₂0.
 
 
 
 
 

2. a.) A molecule of C₂H₆O has a mass of _____________ _______ (units).
 

b.) A mole of C₂H₆O molecules has a mass of ______________ ________ (units).
 

c.) 3 moles of C₂H₆O contain _____________ moles of C, _____________ moles of H,
 

and ____________ moles of O.
 
 

d.) 3 moles of C₂H₆O contain ___________________ atoms of C.
 
 
 
 
 

e.) 15.1 grams of C₂H₆O equals______________moles of C₂H₆O and contains______________ molecules of C₂H₆O.
 
 
 
 
 
 
 

3. Consider the following reaction: 4Al + 3O₂ ------> 2Al₂O₃

a.) How many moles of aluminum oxide can theoretically be formed from 3 moles of aluminum?______
 
 
 
 

b.) _{How many grams of oxygen are required to react with 8.09 grams of aluminum?}
 
 
 

4. Consider this reaction: 2H₂ + O₂ -----> 2H₂O

6.00 grams of H₂ are allowed to react with 48.0 grams of O₂. Determine which of these two is the limiting reactant. Show all calculations and explain your reasoning in choosing the limiting reactant.
 
 
 
 
 
 
 
 
 
 
 
 

5. a.) Write the oxidation number of each element above the element.

__ __         __                 __         __ __
WO₃ + 3H₂ -----> W + 3H₂O

b.) Which of the two reactants gets oxidized?___________reduced?__________

c.) How many electrons are lost?________ How many electrons are gained?_________

d.) The oxidizing agent is______________. The reducing agent is_______________.
 
 

6. Assign an oxidation number to the atoms in boldface:

a.) K₂Cr₂O₇ ______ b.) VO₂^- _______ c.) N₂O ________
 

7. Give two definitions for the process of oxidation (your outline listed four.)
 
 
 

_{8. Write the balanced equation for a neutralization reaction of your choice.}
 
 

_{9. Balance the following equations:}

a.)     H₂S +     I₂ ----->       HI     +       S

b.)    Fe(OH)₃ +     H₂SO₄ ------>     Fe₂(SO₄)₃ +         H₂O

c.)     C₂H₄ +     O₂ ----->     CO₂ +     H₂O

_{10. Write the products, balance each reaction, and identify the reaction as a combination, decomposition, double displacement, single replacement reaction, neutralization, or combustion.   If no reaction occurs, simply write NR.}
 
a.)     Pb(NO₃)₂ + NaI -----> ________________________

b.)     NH₄Cl + K₂SO₄ -----> ________________________

c.)       Ca + AgNO₃ -----> ________________________

d.)       Mg + O₂ -----> ________________________

e.)        F₂ + NaCl -----> ________________________
 

_{10. For the following reaction give the physical state (aq, s, l, or g) in parentheses by each reactant and product.}

        Ba(NO₃)₂     +     2KOH     ------> Ba(OH)₂     +     2KNO₃
 
 

_{Write the net ionic equation for the above reaction:}
 
 
 
 
 
 
 
 
 

11. 196.4 kcal of heat are given off when elemental sodium and chlorine react by the equation below:

2Na_(s) + Cl_2(g) -----> 2NaCl_(s)

a.) Place “196.4 kcal” in the above reaction on either the product or reactant side of the equation, as
appropriate.

b.) Is this reaction exothermic or endothermic? ___________________

c.) What is the sign of DH for this reaction - positive or negative? __________________

d.) How much heat is given off when 1 mole of sodium reacts with chlorine?_________________