Chemistry Midterm Exam Review Sheet Spring 2012
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1. Know your safety rules
2. A shopping mall wanted to determine whether the more expensive “Tough Stuff” floor wax was better
than the cheaper “Steel Seal” floor wax at protecting its floor tiles against scratches. One liter of each
brand of floor wax was applied to each of 5 test sections of the main hall of the mall. The test sections
were all the same size and were covered with the same kind of tiles. Five (5) other test sections received
no wax. After 3 weeks, the number of scratches in each of the test sections was counted.
Identify the following components of an experiment.
a.
Problem: The Effect of the (changes in the independent variable) on the (dependent variable) –
write it using this format
b.
Hypothesis: If the (independent variable – describe how it will be changed), then the (dependent
variable – describe the effect). -- write it using this format
c.
Independent variable d.
Dependent variable –
e.
f.
g.
Control Repeated trials –
Constants –
3. State the law of conservation of mass.
4. Distinguish between the following word pairs (terms):
a. homogeneous mixture and heterogeneous mixture –
b. element and compound –
5. Identify the following as a heterogeneous mixture, compound, element, or homogeneous mixture:
a. salt water
b. gold
c. water
6. Distinguish between a physical and a chemical change.
7. Identify the following changes as physical or chemical:
d. Italian dressing
a. water freezing
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b. paper burning -
c. wax melting -
d. metal rusting -
8. Identify the following properties as physical or chemical:
a. density
-
b. flammability -
c. reactivity –
d. temperature -
9. Distinguish between an endothermic and an exothermic reaction.
10. List the six phase changes and state if they are endothermic or exothermic.
11. How do intensive properties differ from extensive properties?
12. Label each of the following properties as intensive or extensive.
a. mass
b. density
c. length
e. volume
f. boiling point
g. color
d. melting point
13. Compounds can be separated ______________. Mixtures can be separated __________. List 3
separation techniques that can be used to separate mixtures and explain how they work.
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1. How does qualitative data differ from quantitative data? Give an example of each.
2. What is the percent error equation?
3. A student measured a piece of steel pipe and found its length to be 5.4 m. The accepted length of the steel
pipe is 5.1 m. Calculate the percent error.
4. Convert the following temperatures.
a. 38oC = _____________ K
b. 543 K = _____________oC
c. 50°C is equal to ______ Kelvin.
5. You report four measurements of mass, 7.52 g, 7.50 g, 7.51 g, 7.50 g. If the correct measurement is 7.85 g,
are these measurements accurate? _____ Are they precise? ____ Explain your answer.
4. Describe how you add or subtract numbers using significant figures?
5. Describe how you multiply or divide numbers using significant figures?
6. Identify the number of significant figures in the following measurements:
a. 1.00 g
b. 0.0035 g
c. 0.004500 g
d. 101 g
7. Perform the following operations. Keep the correct number of significant figures.
a. 4.56 cm x 9.1 cm =
b. 20.0 ÷ 4 =
c. 7.1 + 6.00 =
d. 8.0 – 4 =
8. List the appropriate SI unit for the following measurements. Define temperature and mass.
a. Length
b. mass
c. volume
d. temperature
e. time
f. quantity
9. Perform the following unit conversions: Use the factor label (dimensional analysis) method.
a. 44 mm = _______________ km
b. 15 lbs = ______________ mg (1lb = 454 g)
c. 5.0 x 106 sec = ___________ days
d. 14,110 ft = _______________ m (1m = 1.0936 yards)
10. How should all equipment be read? Read the following balance to the appropriate precision.
11. List the equipment that can be used to measure volume.
12. Read the following graduated cylinder to the appropriate precision.
13. Describe how you could determine the volume of an irregularly shaped object.
14. What is the formula for density?
15. What is the density of an unknown substance if the mass is 100g and the volume is 100 ml?
16. What is the volume of an object if its density is 1.0 g/cm3 and the mass is 150 g?
17. What is the mass of an object if its density is 4.5 g/ml and the volume is 75 ml?
18. Given two substances, how do you know which one will float?
19. What type of physical property is density, intensive or extensive? What does that mean?
1. What is an atom?
2. List the 2 regions of an atom. What do they give to the atom?
3. List the 3 subatomic particles, their charges, their relative masses and their location in the atom.
4. Who discovered the nucleus in the famous “gold foil” experiment? What conclusions were drawn from this
experiment?
5. Who proposed the first atomic theory in the 1800’s? What has been changed?
6. Who discovered the electron?
7. Which number identifies the element?
8. What is the mass number equal to?
9. How are the numbers of neutrons determined?
10. How are the numbers of electrons determined in a neutral atom?
11. How are the numbers of electrons determined in a cation?
12. How are the numbers of electrons determined in an anion?
13. Besides the atomic number, what other number is found on the periodic table. What is it and give its
definition.
14. Define isotope. Given the following nuclide, explain all the numbers.
+3
. Tell how you would find
the number of protons, neutrons and electrons and then do so.
15. Calculate the average atomic mass for element Z, if it has the following isotopes:
Z-56
Z-57
25%
75%
55.98 amu
56.99 amu
16. Define the following
a. ion
b. cation
c. anion
17. Complete the following chart:
Element
Atomic # Mass # # Protons # Electrons
6
# Neutrons
Symbol (Nuclide)
14
-1
Uranium-238
Magnesium-24
10
PERIODIC TABLE
1. The periodic table is divided into three main categories. Name them and give their location on the periodic
table and their properties.
2. Mendeleev arranged the periodic table by increasing atomic ______. Moseley arranged the modern periodic
table by increasing atomic _______.
3. Distinguish between groups and periods.
4. Which of the following elements have similar properties? Why?
Ca, K, Kr, Cl, Br
5. Give the names of the following groups.
a. Group 1
c. Group 2
b. Group17
d. Group 18
6. Where are the transition metals? Inner transition metals?
7. Which Group contains the most reactive metals? Reactive nonmetals?
8. Give the group and period for the following elements:
a. helium –
b. bromine -
c. calcium -
d. copper –
9. Identify the number of valence electrons present in the following elements:
a. Radium
b. Iodine
c. Cesium
d. Aluminum
e. vanadium
10. Draw an electron dot structure for the following then predict the oxidation number or charge:
a. Nitrogen
b. argon
c. magnesium
d. sodium
e. aluminum
f. sulfur
g. silicon
h. fluorine
11. Which group of elements on the periodic table is most likely to donate one electron?
UNIT 4 IONIC BONDING AND ACID NAMING
1. Which elements lose electrons? Gain electrons? Why?
2. Why do ions have a + or – charge?
3. How many electrons are lost or gained if an ion has the following charge:
a. +1
b. +2
c. +3
d. +4
e. –4
f. –3
g. –2
h. –1
4. What elements are “Stable” (lowest energy state)?
5. How many valence electrons are needed for an element to be considered stable? _________ This known
as the _____________ Rule.
6. Name the following ionic compounds:
a. CaBr2
e. SnBr4
b. KF
f.
c. Mn(OH)2
g. Cu2O
Na2CO3
d. BeS
h.
PbCl2
7. Write the formulas for the following ionic compounds.
a. Sodium fluoride
d. Iron (III) sulfate
b. Calcium nitrate
e. Sodium bicarbonate
c.
f. Lead (IV) Phosphate
Magnesium nitride
8. List the rules for naming acids.
9. Write the formulas for the following acids.
chloric acid
phosphorous
sulfuric acid
___________________
acid
___________________
___________________
10. Name the following acids.
HCl
_________________
H2S
_________________
HNO2
_________________
11. Identify the properties of ionic compounds.
12. Draw the Lewis Structures for the following ionic compounds: sodium chloride, magnesium fluoride,
Lithium oxide, Aluminum sulfide
UNIT 5 – CHEMICAL QUANTITIES
1. What is the value of Avogadro’s number?
2. How many moles of chromate ions are in 5.50 moles of Pb(CrO4)2 ?
3. Work the following problems.
a. Calculate the mass of 3.57 moles of aluminum.
b. How many moles are in 25.0 g of Fe2O3?
c. Calculate the number atoms in 2.50 moles of Zinc.
d. Determine the number of moles for 3.58 x 1023 formula units ZnCl2?
e. Determine the number of molecules in 25.34 g of CO?
f. Determine the mass in 6.11 x 1025 atoms of sulfur?
4. Calculate molar mass for the following.
a. AlBr3
b. H2O2
c. Mg3(PO4)2
5. Caffeine, a stimulant found in coffee, has the chemical formula C8H10N4O2. Determine the percent
composition of caffeine.
6. Compare molecular and empirical formulas. Be able to determine which compounds have the same
empirical formula.
7. Determine the molecular formula for ibuprofen, a common headache remedy. Analysis of ibuprofen yields a
molar mass of 206 g/mol and a percent composition of 75.7% C, 8.80% H an d15.5% O. (find the empirical
formula first)
UNIT 6 – CHEMICAL REACTIONS
1. List the 7 diatomic elements.
2. Define reactants and products and know where they are located.
3. List the types of reactions and how to identify them.
4. Know the symbols for all the states including aqueous and define aqueous.
5. Write and balance the following chemical equations, showing the states, and identify the type. Can be
more than one.
a. Solid calcium reacts with solid sulfur to produce solid calcium sulfide.
b. Solid aluminum metal reacts with aqueous zinc chloride to produce solid zinc metal and aqueous
aluminum chloride.
c. Aqueous aluminum sulfate reacts with aqueous barium hydroxide to produce solid aluminum
hydroxide and solid barium sulfate.
d. Propane gas (C3H8) reacts with oxygen gas to form carbon dioxide gas (CO2) and water vapor.
e. Solid silver oxide decomposes to produce solid silver and oxygen gas
2. Mixed Naming & Formula Practice:
Name
Formula
Formula
copper (II) hydroxide
FePO4
silver chloride
K2CO3
hypochlorous acid
HClO3
iron (II) sulfate
Cd(NO3)2
ammonium hydrogen sulfate
Cs2C2O4
iron (II) oxide
Na3N
ammonium sulfide
SnI4
magnesium phosphate
HClO3
nickel (II) bicarbonate
SrSO3
potassium dichromate
HNO2
phosphoric acid
Ba(OH)2
cobalt (III) nitrate
H3PO3
tin (IV) bromide
H2S
sodium hydrogen sulfate
PbO
silver chromate
HNO2
Name