Download CST Review Part 2

CST Review
Part 2
1. In the phase diagram, correctly label the x-axis and the triple point write the
names of all six phases transitions in the arrows provided.
Liquid
Melting
Freezing
Evaporation
Pressure
(ATM)
Condensation
Solid
Triple Point
Gas
Sublimation
Deposition
Temperature
2. How many protons and electrons do the following atoms have?
Protons
Electrons
A.
H
1
1
B.
Mg
12
12
C.
Cl
17
17
D.
Fe
26
26
E.
Kr
36
36
3. How many protons and electrons do the following ions have?
Protons
Electrons
A.
H+
1
0
B.
Mg2+
12
10
17
18
C.
Cl
D.
Fe2+
26
24
3E.
N
7
10
4.
5.
6.
7.
What is the pH range for an acid?
Less than 7
What is the pH range for a base?
Greater than 7
What is the pH range for a neutral substance?
Exactly 7
Complete the following table
[H+]
pH
[OH-]
pOH
10-5 M
10-7
10-10
10-2 M
10-5
10-12
5
7
10
2
3
12
10-9 M
10-7
10-4 M
10-12
10-11
10-2
9
7
4
12
11
2
Acidic, Basic
or Neutral
Acidic
neutral
basic
Acidic
Acidic
basic
Conservation of Matter and Stoichiometry
State Standard #3 The conservation of atoms in chemical reactions leads to the
principle of conservation of matter and the ability to calculate the mass of
products and reactants. As a basis for understanding this concept:
a. Students know how to describe chemical reactions by writing balanced
equations.
b. Students know the quantity on mole is set by defining one mole of carbon
12 atoms to have a mass of exactly 12 grams.
c. Students know one mole equals 6.02 x 1023 particles (atoms or molecules).
d. Students know how to determine the molar mass of a molecule from its
chemical formula and a table of atomic masses and how to convert the
mass of a molecular substance to moles, number of particles, of volume of
gas at standard temperature and pressure.
e. Students know how to calculate the masses of reactants and products in a
chemical reaction from the mass of one of the reactants or products and
the relevant atomic masses.
8. Write everything you know about a mole. (b,c)
A mole is based on Carbon-12 and has 6.02 x 1023 particles
B. Balancing Equations by Writing Coefficients
A balanced chemical equation contains equal numbers of each kind of atom on
both sides of the equation. In balancing equations, only coefficients – never
subscripts – may be changed. Balance the following equations by filling in the
proper coefficients before the given formulas.
9. __2__Rb + ____Cl2 Æ __2__RbCl
10. ____Si + __2__Br2 Æ ____SiBr4
11. ____CuCl2(aq) + __2__AgNO3(aq) Æ _____Cu(NO3)2(aq) + __2__AgCl(s)
A. Conservation of Mass and Atoms
The total number of atoms of each kind must remain the same in a chemical
reaction. How many atoms of each kind should be present among the product
molecules and formula units in reactions involving the following reactants?
12. Fe(NO3)3 + 3LiOH
Number of Fe atoms _1__
Number of N atoms _ 3__
Number of O atoms 12_
Number of Li atoms _ 3__
Number of H atoms _ 3__
B. Mole Calculations
One mole of a molecular substances contains 6.02 x 1023 molecules. Given
a sample with a certain mass, it is possible to calculate the number of moles in the
sample by dividing the mass of the sample by the molar mass. The number of
molecules can then be calculated by multiplying 6.02 x 1023
Fill into the table the molar mass for each of the following substances.
Next, calculate the number of moles and molecules present in the given sample
mass and fill these quantities into the table. Use the blank space below for your
calculations.
13. Complete the following table
Substance
Formula
Molar
Mass of
Number of Number of
Mass
Given
Moles
Molecules
Sample
Bromine
Br2
159.8
40.0g
0.25
1.506 x 1023
Carbon
Dioxide
Nitrogen
CO2
44
17.6g
0.4
2.408 x 1023
N2
28
154.0g
5.5
3.311 x 1024
C. Converting Grams and Moles
Molar mass is used in gram-mole conversions. Gram divided by molar
mass yields moles. Moles times molar mass yields grams.
Convert the following to moles, referring to a periodic table to obtain
atomic masses. Use the space provided to do your calculations, and write your
answers in the blanks.
x
1 mole
_____2 moles____
14. 34.0g NH3
17g
15. 51.4g Na2O
x
1 mole
62g
____0.829mles___
Convert the following to grams.
16. 17.1 moles H2O x
17. 6.45 moles Cr2O3
A.
x
18g
mole
_____307.8g_________
152g
mole
___980.4g___________
Stoichiometry Calculations
A balanced equation reveals mole ratios, which can be converted, as
needed, into information in grams, and used to solve stoichiometry problems.
Solve the following. Write a balanced equation for each. Then, after
carrying out calculations in the space provided, write your answers in the
blanks.
18. How many moles of hydrogen gas are needed to react with 15.1g chlorine gas, to
produce hydrogen chloride gas?
Equation:
Cl2 + H2 Æ 2HCl _________________
15.1g x 1 mole =
70.9
0.2129 moles Cl2
0.2129 moles Cl2 x 1molesH2 = 0.2129moleH2
1molesCl2
Gases and Their Properties
State Standard #4 The kinetic molecular theory describes the motion of atoms
and molecules and explains the properties of gases. As a basis for understanding this
concept:
a. Students know the random motion of molecules and their collisions
with a surface create the observable pressure on that surface.
b. Students know the random motion of molecules explains the diffusion
of gases.
c. Students know how to apply the gas laws to relations between the
pressure, temperature, and volume of any amount of an ideal gas or
any mixture of ideal gases.
d. Students know the values and meanings of standard temperature and
pressure (STP).
e. Students know how to convert between the Celsius and Kelvin
temperature scales.
f. Students know there is no temperature lower than 0 Kelvin.
19. What creates observable pressure?
Random motion of molecules
20. How can you explain diffusion of gases?
Gases go from an area of high concentration to a low concentration
21. States Boyle’s Law (page 418) in words and give the equation. What is kept
constant?
Boyle’s Law says that volume and temperature are directly related when pressure
is held constant.
22. State Charles Law (page 420) in word and give the equation. What is kept
constant?
Charles Law says that volume and pressure are indirectly related when
temperature is held constant.
23. What is STP (page 300-301)
Standard temperature = 0 C or 273K
Pressure 1 atm or 760mmHg
24. You have a 25L gas sample at 25 C. What will the volume be if you increase the
temperature to 50 C (hint first change the temperatures to Kelvin) V1T2 = V2T1
(25L)(323K)
=
27.09L
298K
25. Your have 10L of gas at 273K. You decrease the volume to 8L what will the new
temperature be? V1T2 = V2T1
T2 = V2T1
(8L)(273K) =
218.4K
10L
V1
26. You have 10L of gas at 1 atm pressure. What will the pressure be if you increase
the volume to 15L? P1V1 = P2V2
(10L)(1 atm)
=
0.667 atm
15 L
27. You have 10L of gas at 2 atm pressure. What will the volume be if you decrease
the pressure to .5 atm? P1V1 = P2V2
(10L)(2 atm)
=
40 L
0.5 atm
The Ideal Gas Law is PV = nRT where P is pressure V is volume n is
moles R is the universal gas constant and T is temperature.
R = 0.0821 atm L
mol K
R = 62.4 mmHg L
mol K
28. You have 5 moles of gas at 1 atm pressure and 273 K. Use the correct R value to
solve for how much volume you have.
V = (5 moles)(0.0821 atm L)(273K)
=
112.06L
V = nRT
P
(mole K) (1 atm)
29. Your have 5L of gas at STP how many moles of gas do you have? (Use value for
STP in the problem)
n = PV
n = (1 atm) (5 L) (moles K)
=
0.223 moles
RT
(0.0821 atm L) (273K)
Temperature
K = C + 273
30. 110 oC = K
383
C = K – 273
31. 25 oC = K
298
32. 298 K = oC
25 oC
33. 110 K = oC
-163 oC
34. What is absolute zero? ___-273 oC and 0 K_________________
35. When a compound that has an ionic bond is dissolved in water if forms ions. If an
electric current is added to the solution the current can be carried and the solution
can conduct electricity. Solutions that can conduct an electric current are called?
electrolyte
36. Which of the following compounds has an ionic bond? (something from the left
side of the periodic bonded with something from the right side)
A.
NaCl
ionic
B.
KF
ionic
C.
NF3
D.
O2
37. What do you use the following equipment for?
A.
graduated cylinder
used to measure volume
B.
Beaker
used to hold a liquid
C.
Erlenmeyer Flask
used to hold a liquid that needs to be swirled
D.
Balance
used to determine the mass of a substance
38. What is the role of a catalyst in a chemical reaction?
A catalyst lowers the activation energy
39. Draw a reaction diagram for an endothermic reaction and for an exothermic
reaction. Label the products and the reactants. Show how adding a catalyst and
inhibitor would change the activation energy for the diagrams.
Endothermic
Energy
Products
Reactants
Process of Reaction
Inhibitor is in red
Catalysis is in blue
Exothermic
Energy
Reactants
Products
Inhibitor is in red
Catalysis is in blue
Process of Reaction
40. Predict how the following would change the direction of the given the following
exothermic reaction at equilibrium. Briefly support your answer. Will it “shift to
the left or shift to the right.”
N2 + 3H2 Æ 2 NH3 + heat
a)
Increase in the concentration of N2. Shift to the right
b)
The equilibrium mixture is heated. Shift to the left
c)
Product NH3 is removed as it is produced. Shift to the right