CHEMISTRY - END OF YEAR FINAL EXAM 2013 UNIT 5

advertisement
CHEMISTRY - END OF YEAR FINAL EXAM 2013
UNIT 5 – CHEMICAL BONDING AND MOLECULAR GEOMETRY
Recognize and use the following terms:
chemical bond
covalent bond
ionic bond
anion
Cation
polyatomic ion
electronegativity
polar
Nonpolar
Lewis dot diagram
molecule
formula unit
SUMMARY OF SKILLS and SAMPLE PROBLEMS
SKILL:
SAMPLE PROBLEMS

Explain how atoms combine to form
compounds through ionic bonding and
covalent bonding.

Classify a chemical bond as covalent, polar
covalent or ionic in nature.
1. Predict the type of bond (ionic, polar covalent, or nonpolar covalent) that will
exist in each compound.
CH4
H 2O
MgF2
CaCl2
NaCl
Br2
2. Explain the distinction between an ionic bond and a covalent bond in terms of
the structure of the compound and the nature of the bond that holds the
compound together.
3. Fluorine monobromide is a polar molecule. Fluorine is a nonpolar molecule.
Sketch the electron cloud of each molecule and explain the differences in
properties between a polar molecule and a nonpolar molecule
1

Use illustrations to predict molecule polarity
and identify molecular and electron
geometry.

Recognize and interpret various models to
illustrate chemical bonding including: Lewis
dot structures and structural formulas.

Use Lewis Dot Structures to predict structure
and bonding of simple compounds.
4. Draw an electron dot diagram for each element below.
K
Cl
C
P
Mg
What do Electron dot diagrams show?
What is the OCTET RULE?
5. Draw a Lewis structure for each of the following
CCl4
CO2
NH3
H2O
6. For each of the structures above predict the SHAPE/GEOMETRY of the
molecule.
Which of these molecules will be POLAR?
Which is likely to dissolve in water?

Determine Molecular and Ionic Formulas for
compounds. Apply IUPAC nomenclature to
name molecular and ionic compounds.
7. Name each compound.
Ionic compounds:
CaCl2
Ca3(PO4)2
FeCl2
NaOH
NH4NO3
Na2SO4
2
Formulas continued…
8. Name each Covalent compound
CBr4
SO
N2P3
BCl3
AsF5
P4O10
9. Write the formula of each compound
Ionic Compounds:
Barium chloride
Ammonium carbonate
Calcium Fluoride
Sodium Sulfite
Sodium oxide
Potassium hydroxide
Covalent Compounds
Iodine monochloride
sulfur triiodide
selenium dichloride
diphosphorus pentoxide
Unit 7- Chemical Reactions
VOCABULARY: Be able to recognize, define, and use the following terms.
Formula Mass
Molecular Mass
Avagadro’s Number
Molar Mass
Mole
Percent Composition
Molecular Formula
Empirical Formula
3
SKILLS AND SAMPLE PROBLEMS
Skill
Calculate the formula mass of a compound given
formula and/or name.
Example Problem(s)
10. NaCl __________
PbSO4_____________________
Potassium nitrate formula_________ formula mass___________
Be able to differentiate between a molecule and
an ionic compound
Convert moles of a given substance to number of
particles and vice versa
Carbon tetrachloride formula_________ formula mass___________
11. Which are molecular? Ionic?
Carbon monoxide _______________
Sodium chloride_________________
Tin (IV) oxide ____________________
Ammonia ___________________
12.
10 moles of sulfur trifluoride
3.2 moles iron (II) oxide
5.25 x 1023 molecules of water
6.19 x 1030 formula units of sodium chloride
Use molar mass to convert grams to moles of a
substance and vice versa
13
100.4 grams of sulfur trifluoride
3.20 grams iron (II) oxide
5.25 moles of water
6.19 moles of sodium chloride
Calculate the percent composition by mass given
of the elements in a compound
14. Laboratory procedures show that 50.0 grams of ammonia, NH 3 , yields 41.0
grams of nitrogen and 9.00 grams of hydrogen upon decomposition. What is the
percent composition of ammonia?
The decomposition of 25.0 grams of Ca(OH)2 in the lab produces 13.5 grams of
calcium, 10.8 grams of oxygen, and 0.68 grams of hydrogen. What is the percent
composition of calcium hydroxide?
4
Calculate the percent composition by mass, given
the formula or name of a compound
15. BF3
Ca(C2H3O2)2
FeF3
Reduce molecular formulas to empirical formulas
16. What is the empirical formula for C8H18 ?
What is the empirical formula for C6H6 ?
What is the empirical formula for WO2 ?
Determine the empirical formula of a compound
given either percent composition or masses
THE EMPIRICAL FORMULA POEM – easy
way to remember the steps in this approach…
% to mass
Mass to mol
Divide by small
Multiply ‘til whole
17. The percent composition of a compound as 40.0% carbon, 6.71% hydrogen,
and 53.3% oxygen.
Decomposing a substance to its elemental parts yields 40.0 grams of carbon, 6.71
grams of hydrogen, and 53.3 grams of oxygen. What is the empirical formula?
A sample of pure indium chloride with a mass of 0.5000 grams is found to contain
0.2404 grams of chlorine. What is the empirical formula of this compound?
Determine the molecular formula of a compound
given either the percent composition and molar
mass or masses.
18. Find the molecular formula for a compound with percent composition of 40.0%
carbon, 6.71% hydrogen, and 53.3% oxygen. The molecular mass of the compound
is 180 g/mol.
A compound has the empirical formula C2H8N and a molar mass of 46 g/mol .
What is the molecular formula of this compound?
5
A compound has the empirical formula C2H4NO . If its molar mass is 116.1 g/mol ,
what is the molecular formula of the compound.
Determine molecular formula continued….
Unit 6- The Mole Concept
Chemical Reaction
Products
Reactant
Balanced Chemical Equation
Coefficient
Subscript
Combustion Reaction
Decomposition Reaction
Double Replacement Reaction
(acid-base neutralization is one type)
Single Replacement Reaction (acidmetal reaction is one type)
Synthesis Reaction
Hydrocarbon
SKILLS: Things you should be able to do
Explain what happens during a chemical reaction
Identify the reactant and products in a chemical
reaction
19. Cu(s) +AgNO3(aq)  Cu(NO3)2(aq) + Ag(s)
HCl(aq)+NaOH(aq)  NaCl(aq) + H2O(l)
Convert verbal descriptions of chemical reactions
into chemical equation and vice versa
20. Solid calcium metal is placed in liquid water to produce aqueous calcium
hydroxide and hydrogen gas.
Aqueous sodium hydroxide is mixed with gaseous chlorine to produce
aqueous solutions of sodium chloride and sodium hypochlorite plus liquid
water.
H2SO4(aq)+NaCN(aq)  HCN(aq) + Na2SO4(aq)
Fe(s) + O2(g)  Fe2O3(s)
6
Use common reaction symbols: (s), (l), (g), (aq) and

Explain the roles of subscripts and coefficients in
chemical equations
Write a balanced chemical equation when given the
unbalanced equation
21. Solid copper reacts with an aqueous solution of silver nitrate to produce a
solution of copper(II) nitrate and solid silver.
\
22. H2SO4(aq) + Al(OH)3(aq)  Al2(SO4)3(aq) + H2O(l)
23. H2SO4(aq) +
Al(OH)3(aq) 
Ba(NO3)2(aq) +
Explain the role of the law of conservation of mass in
a chemical reaction
Na2CO3(aq) 
Al2(SO4)3(aq) +
BaCO3(aq) +
H2O(l)
NaNO3(aq)
24. Fe(NO3)3 + 3 NaOH  Fe(OH)3 + 3 NaNO3
Mass of the Reactant Side:
Product Side Mass:
What is the general format of a hydrocarbon
combustion reaction?
25.
Classify a chemical reaction as synthesis,
decomposition, single replacement, double
replacement, or combustion reactions
26.____ NaBr + ____ H3PO4  ____ Na3PO4 + ____ HBr
Type of reaction: ____________________
____ Ca(OH)2 + ____ Al2(SO4)3  ____ CaSO4 + ____ Al(OH)3
Type of reaction: ____________________
____ Mg + ____ Fe2O3  ____ Fe + ____ MgO
Type of reaction: ____________________
____ C2H4 + ____ O2  ____ CO2 + ____ H2O
Type of reaction: ____________________
____ PbSO4  ____ PbSO3 + ____ O2
Type of reaction: ____________________
Predict the products of simple reactions
27. ____ NH3 + ____ I2 
Type of reaction: ____________________
____ H2O + ____ SO3 
Type of reaction: Synthesis
____ H2SO4 + ____ NH4OH 
Type of reaction: ____________________
7
UNIT 8 – STOICHIOMETRY
Recognize and use the following terms:
Reactant
product
mole ratio
coefficient
formula unit
limiting reactant/reagent
excess reactant/reagent
theoretical yield
actual yield
percent yield
SKILL:
SAMPLE PROBLEMS
Interpret chemical equations in terms of
molecules, formula units, and moles
28.Balance each, then determine how many moles/molecules/formula units of each
reactant and each product?
H2O2 
O2 +
H2O
AgNO3 + Cu --> Cu(NO3)2 + Ag
Calculate moles of a reaction component given
moles of another reaction component (mole to
mole problems).
29. H2SO4 + 2NaOH  Na2SO4 + H2O - If reaction completely consumes 4
moles of NaOH, how many moles of sodium sulfate will be produced?
2H2 + O2  2H2O If 6 moles of oxygen react with excess hydrogen, how many
moles of water are produced?
Calculate the mass of a reaction component
given the mass of another reaction component
(mass to mass problems).
30. Ba(OH)2 + HNO3 --> Ba(NO3)2 +
H2O
In the above unbalanced reaction, if the 1.67g of barium hydroxide is completely
reacted with an excess of nitric acid, how many grams of water will be produced?
4Fe (s) + 3O2(g) --> 2Fe2O3
In the above reaction, if 5.88g of iron (III) oxide is produced, how many grams of
iron were needed?
8
Be able to use a given volume of a gaseous
reaction component to find the moles, or mass of
another reaction component. Or given a mass or
molar amount of a reaction component, calculate
the volume of a gaseous reaction component.
31. C2H4(g) + 3O2(g) --> 2CO2(g) + 2H2O(g)
If the above combustion reaction consumes 2.43L of oxygen, how many liters of
carbon dioxide will be produced?
(GAS STOICHIOMETRY)
If the above reaction consumes 34.7g of ethene (C2H4), how many liters of water
vapor will be produced?
Determine Limiting and/or excess reactant in a
reaction given masses or moles of reactants.
32. CaO(s) + SiO2(s)
CaSiO3(s)
Calcium silicate can form from the reaction of calcium oxide with silicon dioxide
as shown in the balanced equation above.
What is the limiting reagent when 89.2 g of CaO reacts with 120.8 g of SiO2?
Determine the mass of an excess reactant left
over in a reaction.
What is the theoretical yield of calcium silicate product in the above reaction?
Determine the mass of excess reagent in the above reaction.
Calculate the percent yield of a chemical process
given the actual yield of the reaction and
sufficient information to calculate the theoretical
yield.
33. Use your theoretical yield from the above problem. If a chemist does the
reaction with the masses of reactants given above, and finds an actual yield of
154.4g of calcium silicate, calculate the % yield of the reaction.
9
UNIT 9 – Gas Laws and Kinetic Molecular Theory
Recognize and use the following terms:
VOCABULARY: Be able to recognize, use and define the following terms.
Pressure
Volume
Temperature
Kelvin Temperature Scale
Celsius Temperature Scale
Mole
Directly Proportional
Inversely Proportional
Ideal Gas
Boyle’s Law
Charles’ Law
Avogadro’s Law
Combined Gas Law
Gay-Lussac’s Law
Kinetic Molecular Theory
Partial Pressure
Molarity
STP conditions
Skills: Things you should be able to do.
Skill(s)
Sample Problem
Recognize direct and inverse
proportionalities between variables in
an equation or when shown a graphical
view of the relationship.
34. Directly proportional or inversely proportional?
k = PV
k = V/T
P 1/T1 = P2/T2
Sketch a coordinate graph to represent each of the above relationships.
10
Use Boyle's, Charles', Gay-Lussac's
and/or the Ideal Gas laws to predict
how a change in one gas variable will
affect another variable.
35. How many moles of gas are in a container at a temperature of 21 C if the gas exerts a
pressure of 755mmHg and the volume of the container is 455mL?
Find the final volume of a gas that was occupying 0.50L of space at a pressure of
1.05atm if the pressure is increased to 1.244atm assuming that temperature remains
constant.
12.6L of gas fills a balloon at 294K. What is the new volume of the balloon when the
temperature is decreased to 12.0C?
Describe the assumptions made about
the properties of a theoretical ideal
gas.
36.
Detail the conditions under which real
gases behave ideally and the
conditions where real world gases do
not behave like ideal gases.
37.
Use gas laws and stoichiometry to
solve the following problems.
38.
2Na(s) + 2H2O(l)→2NaOH(aq) + H2(g)
A. If 3.67g of Na reacts completely with an excess of water, what volume of hydrogen
will be produced at 35oC, 893 torr, and 3.21 L ?
B. A student carried out the above reaction. She collected 0.617L of hydrogen at 25
degrees Celsius and 1.05atm. How many moles sodium were consumed in the reaction?
11
Use partial pressures to solve the
following problems
39.
1.
If a steel container holds 5.00 moles of gas and the total pressure is 5.00
atm., what is the partial pressure for each mole of gas?
2.
If a steel container holds 2.00 moles of hydrogen gas and 2.00 moles of
helium gas, and the total pressure is 4.00 atm., what is the partial pressure of
each of the gases?
3.
If a steel container holds 1.00 moles of oxygen gas and 3.00 moles of
argon gas and the total pressure is 800 Torr, what is the partial pressure of
each of the gases?
4.
If a steel container holds 1.50 moles of nitrogen gas and 2.50 moles of
helium gas at a total pressure of 760 mm Hg, what is the partial pressure of each
of the gases?
12
Download