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Chemistry L3 Midterm Exam Review Problems
1. Physical or chemical change?
a. Iron rusting
b. Paper burning
c. Crumpling paper
2. Convert 150km to m
3. Convert 1.56x105cm to km
4. Convert 654214dg to ng
5. Convert 45 mi/hr to m/s
6. Convert 678 mL/s to L/hr
7. Mrs. Neuman walks/runs on a semi-regular basis. She walks/runs for 45 minutes 3 days a week. She averages
out to moving 4.75 miles per hour. How many meters has Mrs. Neuman walked/ran after 12 weeks? (1.61 km =
1 mile)
8. Convert 35 °F to °C.
9. Convert 313K to °F.
10. Put the following numbers in scientific notation:
a. 0.00135
b. 14569.34
11. Take the following numbers out of scientific notation
a. 3.45 x 103
b. 7.89 x 10-5
c. 6.23 x 100
12. How many sig figs are in the following numbers:
a. 5005
b. 600.
c. 50
d. 3.40 x 105
e. 0.7521
f. 0.009140
13. Round the following numbers to 4 sig figs:
a. 16995
b. 87.297
c. 40001
14. What is the formula for density?
a. What is the unit for mass?
b. What is the unit for volume?
c. What are the units for density?
15. What does a cubic centimeter equal?
16. Find the density of a block of wood with a mass of 25.00 g and a volume of 80.000 cm3
17. An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2 ml. The
height of the water rose to 7 ml. If the mass of the stone was 25 g, what was its density?
18. What is the voume of a sample of a metal that has a mass of 0.40g and a density of 11.7g/mL?
19. Mrs. Stabile is terrible a darts. All of her darts hit the wall outside of the dartboard in a small cluster.
a. Is Mrs. Stabile accurate when she plays darts?
b. Is Mrs. Stabile precise when she plays darts?
20. In lab, you find the density of an object to be 5.16 g/mL. The actual density is 4.75 g/mL. What is your percent
error?
21. What is important about the BrInClHOF elements?
22. What are isotopes?
23. Naturally occurring magnesium has three isotopes:
Isotope
Abundance
Mass
24
Mg
78.99%
23.985amu
25
Mg
10.00%
24.986amu
26
Mg
11.01%
25.983amu
What is the average atomic mass of magnesium? Show all work, sig figs, and units!!
Chemistry L3 Midterm Exam Review Problems
24. Fill-in the chart:
133
Cs
Symbol
55
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
Protons
Neutrons
Electrons
Atomic Number
Mass Number
Average Atomic Mass
Name the following compounds:
a. HCl
b. MgCl2
c. PCl5
d. HBrO3
e. HClO2
Balance the following ionic compounds (criss-cross method)
a. Lithium sulfide
b. Calcium bromide
c. Cuprous chloride
Name the type of reaction:
a. C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
b. 8 Fe + S8 ---> 8 FeS
c. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g)
d. 2 H2O ---> 2 H2 + O2
e. Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3
Balance the following reactions:
a. HgO  Hg + O2
b. Al + Pb(NO3)2  Al(NO3)3 + Pb
Predict the products of the following reactions:
a. Ca(BrO3)2 + Na 
b. F2 + MgCl2 
c. CdBr2 + I2 
Use your solubility rules to predict the products and balance the equations.
a. Na2CO3 + Ca(NO3)2 
b. NaOH + CaCO3 
Redox: Sb + H2SO4  Sb2(SO4)3 + SO2 + H2O
a. Who is oxidized?
b. Who is reduced?
c. Who is the oxidizing agent?
d. Who is the reducing agent?
What is the molecular weight of Ca3(PO4)2?
How many moles are in 562.40g NaHCO3?
How many molecules are in 2.74 moles NaCl?
How many grams are in 7.09 x 1024 molecules of ZnCl2?
Determine the percent composition of CaCl2.
A chemist combines 1.26g iron with 0.56g oxygen to form rust. What is the percent composition of this new
compound?
Cerium (III) iodide (CeI3) occurs as a hydrate with the composition 76.3% CeI3 and 23.7% H2O. Calculate the
formula of the hydrate. Name the hydrate.
A 17.44g sample of a hydrate of zinc sulfate (ZnSO4) is heated strongly in a crucible to drive off all water of
hydration. After heating, the sample has a mass of 9.79g. Calculate the molecular formula for this hydrate.
Name the hydrate.
What’s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen?
If the molar mass of the compound in problem #40 is 110 grams/mole, what’s the molecular formula?