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REVIEW PROBLEMS – MIDYEAR
NAME__________________
1. The volume of water in a graduate rises from 5.0 ml to 20.2 ml when a solid whose
mass is 41.04 g is dropped into the graduate. What is the solid’s density?
2. What volume is occupied by a piece of copper whose mass is 112 g? The density of
copper is 8.9 g/cm3.
3. Convert:
a) 356o K to oC
b) 60.0oC to oF
c) Show the conversion and express the answer in scientific notation:
1) 6560 m to µm
2) 0.0711 cg to kg
3) 0.0052 L to nL
4) 520 nm to cm
5. Calculate the formula mass of:
CuSO4 * 5 H2O
6. Find the gram-formula mass of: (NH4)3N
7. a) How many moles are there in 2.560 g of ethanol, C2H5OH ?
b) How many molecules are in the sample? How many Carbon atoms?
8. Calculate the mass of 0.707 mole of Ba(OH)2.
9. Draw a heat content diagram for the combustion of
CH4. (Δ H = -212.8 kcal/mol)
10. A certain reaction is carried out in a calorimeter, raising the temperature of 37.5 g of
water from 21.0oC to 75.8oC. Calculate the heat of reaction.
11. 173.9 calories of heat are needed to raise 25.0 g of a certain metal from 10.0 oC to
75.0 oC. What is the specific heat of the metal?
12. Calculate the heat released when 50.0 g of Fe2O3 (iron II oxide) reacts with
aluminum as follows:
Fe2O3(s) + 2 Al(s) -----> Al2O3(s) + 2 Fe(s) ΔH = -200. kcal
13. Using handout Table 4.2 and Hess’ Law, calculate ΔH for:
NO(g) + .5 O2(g) -----> NO2(g)
14. Given:
CaO(s) + SO3(g) -----> CaSO4(s)
ΔH = -96.0 kcal
What mass of CaO is needed to evolve 5.00 kilocalories of heat?
15. Convert:
5.47 kJ to kcal.
16. Convert:
732 mm Hg: to kPa.
to atmospheres
17. Calculate the partial pressure of oxygen (O2) in a gas mixture saturated with water
vapor at 23oC. The total pressure is 770. mm Hg.
18. Gas in a storage tank has a volume of 1.50 x 105 m3 at 25oC and atmospheric
pressure. If the temperature falls to -20.oC at constant pressure, what is the new volume
of the gas?
19. A sample of oxygen gas weighing 5.00 g is collected at 20.oC at 752 mm Hg. What
is the volume of the gas?
20. Calculate the density of nitrogen dioxide gas, NO2, at STP.
21. A certain gas has a density 2.18 times greater than that of carbon dioxide (CO2).
What is the molecular mass of the unknown gas?
22. An auto tire at 10.oC contains 105 L of air under 2.90 atm of pressure. After driving
for some time, the tire heats up to 52oC and expands to a volume of 110. L. What is the
pressure of the air inside the tire?
23. Given:
N2(g) + 3 H2(g) -----> 2 NH3(g)
a) Calculate the volume of hydrogen needed to form 4.77 moles of ammonia (NH3) gas
at STP.
b.) If 0.63 g of nitrogen gas is reacting, what volume of ammonia (NH3) is produced, at
STP?
c) What volume of hydrogen is needed to form 11.5 liters of ammonia (NH3) at STP?
24. Which diffuses faster, neon gas or oxygen gas? How much faster?
25. Sodium chlorate (NaClO3) decomposes to form sodium chloride and oxygen gas.
a) Write the balanced equation for the reaction.
b) What mass of oxygen is produced when 0.315 grams of sodium chlorate is
decomposed?
26.
2 Na(s) + I2(s) -----> 2 NaI(s)
What is the maximum mass of NaI (sodium iodide) that can be produced when 0.33 mole
of sodium reacts with 0.85 mole of iodine?
27. Calculate the percentage composition of Ca(NO3)2.
28. 0.77 g of magnesium burns in air to form 1.28 g of magnesium oxide. What are the
percentages of magnesium and oxygen in magnesium oxide?
29. The mass percentages of hydrogen and oxygen in water are 11.2 and 88.8,
respectively. Calculate:
a) the mass of oxygen in 175 g of water
b) the mass of water containing 20.0 g of oxygen
30. 0.490 g of tin (Sn) combines with 0.132 g of oxygen to form tin oxide. Calculate the
simplest formula of the compound.
31. A certain compound is 7.7% hydrogen and 92.3% carbon by mass. If the
compound’s molecular mass is 78, find its molecular formula.
HChemistryMidtermExam
ü Your exam is scheduled for: January 19, 2017 * Period 3 ONLY
ü Your exam should take the two-hour period. Please, bring reading
material in case you finish early. You will not be allowed to leave the
room.
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ü Your exam is divided into 2 parts.
o The first part will be multiple choice. (40 questions)
o The second part will be calculations and short answers (45
questions)
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Usethelistasastudyguide.Keepinmindthatadditionalthings
mayhavebeenaddedandremovedfromeachchapter,souse
yournotesasyourprimarysourceofreference.
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morningby7:05andstayuntil3:15.So,ifyouhavequestionsor
thetimesabovedonotworkforyou,justaskandwecansetup
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availableduringtheperiodswhenIamnotgivinganexam.
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Flip page for chapter outlines…
UNIT 1 (CH. 1) Introduction to Chemistry
Density
Density of water
sig figs
metric conversions
K ⇔ oC, oC ⇔ oF
elements, compounds
mixtures – homogeneous, heterogeneous
temperature scales
definition of temperature
UNIT 2 (CH 2.1-2.4 &3.1): ATOMIC STRUCTURE
particles in atom, location, charge, mass
model of the atom
atomic number, mass number, atomic mass
isotopes – define, # p, n, e
writing chemical formulas
formula mass, gram formula mass, molecular mass
moles ⇔ g ; g ⇔ molecules; moles ⇔ molecules ⇔ atoms
define – atom, molecule, ion
UNIT 3 (CH 3.2 &4.1-4.4): CHEMICAL FORMULAS, QUANTITIES, EQNS
percentage composition
empirical and molecular formulas – calculate, define
equations:
balance
write from descriptions
use to solve problems:
mass/mass, mole/mass, mole/mole
limiting reagent
diatomic elements
UNIT 4 (CH 5): THERMOCHEMISTRY
exothermic, endothermic – signs
heats of fusion, vaporization, formation
heat of combustion
specific heat
calorie
Hess’ law
calorimeter problems (Q = (c)(m)(Δt)
ΔH, given the equation
heat content diagram
ANY SCIENTIST TESTED AND HIS CONTRIBUTION
ANY DEFINITIONS TESTED
REVIEW SYMBOLS!
UNIT 5 (CH 9): GASES
Ideal gas – conditions
Avogadro’s law
Density of gases ( D = MM/22.4L D1/D2 = MM1/MM2) or D=PM/RT
STP
PV = nRT ( R = .0821 L-atm/mol-K)
Combined gas law
Graham’s law of diffusion
Relationships in Boyle’s law, Charles’ law
Dalton’s law of partial pressures
mm Hg ⇔ atm ⇔ kPa
Chem eqns involving gases: mass/vol., vol/vol, mole/vol
Greenhouse effect – See article from homework
UNIT 6 (CH :2.5& 6.5) PERIODIC TABLE
Transition elements – identify, characteristics
lanthanides, actinides
most active metals
most active nonmetals
liquid metal, nonmetal at room temperature
atoms in same period – same # of principal energy levels
Groups - alkali metals, alkaline earths, halogens, noble gases
metals, nonmetals, metalloids – locations, characteristics
define and know trends: ionization energy
electronegativity
atomic radii
elements in same group – similar properties
predicting physical properties, chemical properties
most active metal, nonmetal in a group or period
MISCELLANEOUS: interpreting graphs
REMEMBER:
1 mole of any gas at STP occupies 22.4 L
1 mole
contains
6.022 x 1023 particles - atoms, if element
molecules, if compound/diatomic
1 mole has a mass
of 1 GFM – element – GAM
molecules/diatomic elements – GMM
other - GFM
OR
MOLAR MASS