For multiple choice questions put down all correct answers. Show all of the calculations for which you use a calculator.

1 . For the following two sets of elements: Li, Be, Na C, N, F
 

Which has the lowest electronegativity? ________ ________

Which has the highest ionization energy? ________ ________

Which is the largest? ________ ________
 

a.) required to split an ionic compound into ions.
b.) required to remove a valence electron from a neutral atom.
c.) released when an electron is added to a neutral atom.
d.) released when two oppositely charged ions come together.
e.) required to add an electron to a neutral atom.
 

__ __     __        __ __   __
P₂O₅ + 5C ----> 5CO + 2P

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

c.) The oxidizing agent is_____________. The reducing agent is_______________.
 

a.) loses electrons b.) gains hydrogen c.) loses hydrogen d.) loses oxygen e.) gains electrons

5. Assign an oxidation number to the element in boldface:
 

a.) NO₂^- ______ b.) H₂SO₃ _______

6. Determine the weight % composition of H₂O₂.
 
 
 
 
 

7. Answer the following questions for the compound ethanol, C₂H₆O. Units are important here!
 

a.) Is this compound ionic or covalent?_________________

b.) Do we refer to one atom, one molecule, or one formula unit of this compound?_____________

c.) What is the mass of one ___________________(fill in answer to question b.) of this compound?

d.) What is the mass of one mole of ethanol?______________________.

e.) In 2 moles of C₂H₆O there are:

_______________moles of carbon and __________________ molecules of carbon.
 

_______moles Ca atoms, ________moles N atoms, ________moles O atoms_________

9. A sample of CO₂ weighs 83.5 grams. How many moles of CO₂ is this?_{______________}
 
 

10. A sample contains 2.34 x 10²⁵ atoms of sodium. How many moles of sodium is this?____________
 
 
 

11. For the following chemical reaction: P₂O₅ + 5C -----> 5CO + 2P
 

a.) How many moles of P₂O₅ must react to form 6 moles of P? ____________

b.) How many moles of C must react to form 4 moles of CO? _____________
 
 

c.) How many moles of C must react to form 3 moles of P? _____________
 
 
 

d.) How many grams of phosphorus can be formed by reacting 5.00 grams of P₂O₅? _________
 

e.) If you performed this reaction in lab, using 5.00 grams of P₂O₅ ( as in d. above), and obtained

1.68 grams of phosphorus what is your % yield? _____________
 

12. Glucose is metabolized by the body according to the following reaction and 686 kcal of energy
is given off per mole of glucose. C₆H₁₂O₆ + 6O₂ -----> 6CO₂ + 6H₂O
 

a.) Is the reaction considered endothermic or exothermic?_____________________

b.) Is the sign of DH, the heat or enthalpy of the reaction, going to be (+) or (- )? ________

c.) Would you write 686 kcal on the left or the right side of the arrow in the above equation?_______

d.) How many kcal of heat will be given off if 295 grams of glucose is metabolized? ___________