1. Announcements
Exam #1: Tonight!, 7:00-8:30pm, locations posted on website, bring ID
Conflict Exam: 5:00-6:30pm, 162 Noyes, bring ID
No book homework due Friday!
Lecture on Thursday! (New Material – Pre-lecture assignment still due at 8:00 am Thursday)
Exam scores posted late Wednesday evening. Get graded exams back on Friday.
Liquid nitrogen ice cream winner = highest section average!!!

2. Chemistry Joke of the Day
Q: What do chemists call a benzene ring with iron atoms replacing the carbon atoms?
A: A ferrous wheel.

3. Exam Format – 90 minutes total
15 Multiple Choice Questions
2 Free Response Questions
5 possible choices
50% of test grade
~3 minutes to answer each (~45 min on this half of exam)
Write in answers – both qualitative and quantitative
50% of test grade
~45 minutes on this half of exam
***A periodic table & cover sheet with
equations will be attached.***

4. Clicker #1 What is the molar mass of nickel(II) carbonate?
a) g/mol
b) g/mol
c) g/mol
d) g/mol
e) g/mol

5. Clicker #2
A g of carbon dioxide and g of dinitrogen tetroxide are mixed in a rigid steel container. Which of the following is true regarding the partial pressures of the two gases?
The partial pressure of carbon dioxide is half that of dinitrogen tetroxide.
The partial pressure of the gases is the same.
The partial pressure of carbon dioxide is twice that of dinitrogen tetroxide.
The partial pressure of carbon dioxide is four times that of dinitrogen tetroxide.
Without knowing either the temperature or the volume of the gases, it is impossible to draw any conclusions about the partial pressures of the two gases.
Follow up: Explain based on kinetic molecular theory – why does CO2 have a higher partial pressure than N2O4?

6. Clicker #3
If a gaseous mixture is made of 3.50 g of He and 5.75 g of Ar in an evacuated 2.05-L container at 25°C, what will be the partial pressure of Ar in the container? a) 1.72 atm b) 5.75 atm c) 10.4 atm d) 11.9 atm e) 12.1 atm
Follow up: What is the total pressure in the container?

7. Clicker #4
A compound consists of silicon and 8.23% by mass of hydrogen. The molar mass of the compound is approximately 122 g/mol. What is the molecular formula of this compound?
a) Si4H10
b) SiH2
c) SiH3
d) Si2H5
e) Si4H12

8. Clicker #5
A member of the alkaline earth metal family whose most stable ion contains 36 electrons forms a compound with bromine. What is the correct formula for this compound?
CaBr2
BaBrO3
KrBr
RbBr
SrBr2

9. Clicker #6
You are given lbs. of magnesium phosphate. How many moles does this represent? (1 kg = lbs, 1 kg = 1000 g)
a) 1.35 mol
b) 1.54 mol
c) 2.98 mol
d) 93.6 mol
e) 206 mol

10. Clicker #7 Which of the following is true regarding ?
# protons # electrons # neutrons mass number a) b) c) d) e)

11. Clicker #8
15. If you have equal mole samples of each of the following compounds, which compound contains the greatest number of oxygen atoms?
magnesium nitrate
dinitrogen pentoxide
iron(III) phosphate
barium oxide
potassium acetate

12. Clicker #9 Which sample contains the greatest number of atoms?
10.0 g Na
10.0 g Fe
10.0 g Ag
10.0 g Cu
10.0 g Ba

13. Clicker #10
Which of the following statements is true?
An g sample of water contains × 1023 molecules of water.
The mass of one nitrogen atom is g.
If five “units” of iron(III) nitrate is dissolved, there will be 65 particles in solution.
One mole of sodium (Na) is equal to atomic mass units (amu).
For every one mole of magnesium phosphate, there are six moles of oxygen atoms present.

14. Clicker #11
A flexible weather balloon contains helium gas at a volume of 855 L. Initially, the balloon is at sea level, where the temperature is 25oC and the barometric pressure is atm. The balloon then rises to an altitude of 6000 ft, where the pressure is atm and the temperature is 15oC. What is the change in the volume of the balloon as it ascends from sea level to 6000 ft?
128 L b) 373 L c) 610. L d) 983 L
e) none of these?

15. Clicker #12
A gas sample containing 2.50 mol at 25°C exerts a pressure of 1.00 atm. Some gas is added to the same container and the temperature is increased to 50.°C. If the pressure increases to 2.00 atm, how many moles of gas were added to the container? Assume a constant-volume container.
1.25 mol b) 2.11 mol c) 2.50 mol d) 4.61 mol e) 5.00 mol