Download Chemistry Standards Review

Chemistry Standards Review
Homework: Day 3
1. How many hydrogen atoms are in one mole of sulfuric acid, H2SO4?
(A) 1.20x1023
(B) 3.01x1023
(C) 6.02x1023
(D) 1.20x1024
2. The atomic mass of calcium is 40.078 amu. If a chemist measures out 120.234 g of calcium,
and all of it reacts with oxygen to form calcium oxide, CaO, how many moles of calcium
oxide are present?
(A) 0.33333 mol
(B) 1.0000 mol
(C) 1.3333 mol
(D) 3.0000 mol
3. Aluminum fluoride’s chemical formula is AlF3. What is the ratio of aluminum to fluoride
ions in this compound?
(A) 1:1
(B) 1:2
(C) 1:3
(D) 3:1
4. Molybdenum has a molar mass of 95.94 g/mol. How many moles are present in 150.0 g of
molybdenum?
(A) 0.1563 mol
(B) 0.6396 mol
(C) 1.563 mol
(D) 6.396 mol
5. Based on the table below, what is the average atomic mass of copper?
Isotope
Copper-63
Copper-65
(A)
(B)
(C)
(D)
62.94 amu
63.55 amu
63.93 amu
64.93 amu
Percentage
69.17%
30.83%
AMU
62.94
64.93
6. What is molar mass?
(A) The mass, in grams, of one mole of a substance
(B) The mass, in moles, of one gram of a substance
(C) The mass, in moles, of the amount of reactant produced
(D) The mass, in grams, of the reactant consumed
7. Using the periodic table, what is the molar mass of chlorine gas, Cl2?
(A) 17 g
(B) 34 g
(C) 35.45 g
(D) 70.90 g
8. Using the equation for the combustion of magnesium below, determine how many grams of
oxygen required to burn 10.0 grams of magnesium.
2Mg + O2
2MgO
(A) 2.2 g
(B) 3.3 g
(C) 6.6 g
(D) 13.2 g
9. Sodium reacts with chlorine to form sodium chloride according to the following reaction:
2Na + Cl2
2NaCl
How many moles of Cl2 react with 100 moles of Na?
(A) 1
(B) 50
(C) 100
(D) 200
10. What mass of NH3 can be made from 121 g H2 and excess N2 based on the following
equation?
N2 + 3H2
2NH3
(A) 80.7 g NH3
(B) 121 g NH3
(C) 680 g NH3
(D) 1020 g NH3
11. In the equation below, how many moles of oxygen gas would react with 150 g of C8H18?
2C8H18 + 25O2
(A) 0.11 moles O2
(B) 1.3 moles O2
(C) 12 moles O2
(D) 16 moles O2
16CO2 + 18H20
12. A measure of the average kinetic energy of the particles in an object is the object’s
(A) Heat
(B) Temperature
(C) Mechanical energy
(D) State
13. Look at the equations below. Which of the following statements is true?
CH4 + 2O2
CO2 + 2H2O + energy
N2 + O2 + energy
2NO
(A)
(B)
(C)
(D)
Equation 1 is an endothermic reaction
Equation 2 is an endothermic reaction
Both equations 1 and 2 are exothermic reactions
It is not possible to determine the type of reaction
14. Calculate the change in enthalpy for the following reaction given that the standard enthalpy
of formation for water is -285.8 kJ/mol, for oxygen is 0.0 kJ/mol, and for hydrogen peroxide
is -187.8 kJ/mol.
(A)
(B)
(C)
(D)
-473.6 kJ
-98.0 kJ
98.0 kJ
196.0 kJ
2H2O + O2
2H2O2
15. What is entropy?
(A) A measure of the randomness or disorder of a system
(B) The energy in a system that is available for work
(C) A measure of the average kinetic energy of the particles in an object
(D) The total energy content of a sample
16. What happens to the motion of molecules as temperature increases?
(A) Molecular motion remains the same
(B) Molecular motion decreases
(C) Molecular motion is not affected
(D) Molecular motion increases
17. Before Geoff can calculate the molar enthalpy for a sample, he must convert the initial
temperature and final temperature to the Kelvin scale (K). If Tinitial is 32oC and Tfinal is 0.5oC,
what are the temperatures in kelvins?
(A) 273.15 K and 273.15 K
(B) 305.15 K and 273.65 K
(C) 241.15 K and 272.65 K
(D) -241.15 K and -272.65 K
18. Which of the following statements about temperature and molecular motion is NOT true?
(A) Temperature is determined by the average kinetic energy of particles
(B) Molar heat capacity is related to the specific heat of a substance
(C) Entropy is related to concentration
(D) Temperature is determined by concentration
19. During the operation of a gasoline engine, the piston moves inside the cylinder. What is
happening as the piston compresses the gas in the cylinder?
(A) The size of the gas particles decreases
(B) The volume of the gas particles increases
(C) The pressure of the gas particles increases
(D) The number of collisions between the gas particles decreases
20. Which of the following describes standard pressure and temperature?
(A) 0oC and 0 atm
(B) 1oC and 1 atm
(C) 0oC and 1 atm
(D) 1oC and 0 atm
21. Which of the following statements about diffusion is NOT true?
(A) Diffusion is due to the fast motion of gas molecules
(B) Diffusion involves a decrease in entropy
(C) Diffusion occurs as substances move from an area of higher concentration to an area
of lower concentration
(D) Diffusion eventually results in a homogenous mixture
22. A 1 mol sample of O2 exerts 450 kPa of pressure on the walls of a container. If the
temperature and amount of O2 remain the same, what is the pressure exerted by the gas if it
were in a container that is half the size? Use this formula : P1V1 = P2V2
(A) 225 kPa
(B) 450 kPa
(C) 900 kPa
(D) 1350 kPa
23. An aerosol can contains gas at 150 kPa. Using the formula below, what will the pressure be if
the can is heated from 20oC to 85oC?
P1 = P2
T1 T2
(A) 123 kPa
(B) 183 kPa
(C) 240 kPa
(D) 699 kPa
24. How many moles of gas fill a volume of 18.1 L at 85.4 kPa and 10oC? (R = 8.314)
(A) 0.657 mol
(B) 1.52 mol
(C) 34.0 mol
(D) 18.6 mol
25. Which of these factors can affect chemical equilibrium?
(A) Change in pressure
(B) Addition of a catalyst
(C) Addition of an inert solid
(D) Change in surface area
26. When the rate of its forward reaction is equal to the rate of its reverse reaction, and the
concentration of its products and reactants remains unchanged, a reversible chemical reaction
is said to be
(A) Exothermic
(B) Endothermic
(C) In chemical equilibrium
(D) Shifting equilibrium
27. In a lab experiment, 5 g of NaCl is added to a 2.0M solution of HCl. What is the common
ion?
(A) Cl(B) H(C) Na(D) Na+
28. What would happen if you decreased the concentration of CO2 in the following equilibrium
reaction:
(A)
(B)
(C)
(D)
H3O+ + HCO32H2O + CO2
The forward reaction will increase
The reverse reaction will increase
Both the forward and the reverse reactions will increase
Equilibrium is not affected
29. Which of the following values for Keq shows an equilibrium system with the highest
concentration of products?
(A) 0.02
(B) 0.2
(C) 2.0
(D) 20.0
30. Which equation below is a reversible reaction?
(A) Ba(NO3)2
Ba2+ + 2NO3(B) 2N2 + 6H2O
4NH3 + 3O2
(C) 2HgO
(D) CH4 + 2O2
2Hg + O2
CO2 + 2H2O
31. What is Keq for the following reaction if the concentration of N2O4 is 9.78x10-3 and the
concentration of NO2 is 7.70x10-3
(A)
(B)
(C)
(D)
-3
2NO2
N2 O4
6.06x10
0.787
1.27
165
32. Which of the following statements describes the reaction curve for an exothermic reaction?
(A) The energy is higher before the peak for the energy of activation
(B) The energy is higher after the peak for the energy of activation
(C) The energy is the same before and after the peak for the energy of activation
(D) The energy is higher than the peak for the energy of activation
33. How does increasing temperature increase reaction rate?
(A) It increases the concentration of the reactants
(B) It decreases the collisions between molecules
(C) It increases the pressure on the reaction
(D) It increases the fraction of molecules that have enough energy to react
34. A chemical reaction produces 100 mg of a substance per second at 25oC. If doubling the
temperature increases the rate of production by a factor of 2, how many milligrams would be
produced per second at 50oC?
(A) 50 mg
(B) 100 mg
(C) 200 mg
(D) 400 mg
35. Which of the following statements about pressure and reaction rates is true?
(A) Increased pressure increases the rate of all reactions
(B) Increased pressure increases the rate of reactions taking place in the liquid and gas
states
(C) Increased pressure increases only the rate of reactions taking place in the gas state
(D) Increased pressure increases the rate of reaction only when pressure is doubled
36. What is activation energy?
(A) The energy of bond formation
(B) The energy of the reactants
(C) The energy of the products
(D) The minimum energy required to start a chemical reaction
37. Which of the following statements describes the effect of catalysts?
(A) They increase the reaction rate by lowering the activation energy
(B) They increase the reaction rate by lowering the overall energy of the reaction
(C) They increase the reaction rate by increasing the energy of the reactants
(D) They increase the reaction rate by increasing the energy of the products