chemistry

Question 1
 (Multiple Choice Worth 2 points)

[08.04]Which of the following best summarizes the main causes of water pollution today?

[removed] increased runoff, driving, discarded oil

[removed] evaporation

, new construction, overpopulation

[removed] waste from wildlife, decaying vegetation, automobiles

[removed] leaking septic and sewer systems, manufacturing, farming

  

Question 2
 (Multiple Choice Worth 2 points)

[05.06]When 5.6 grams of NaCl are dissolved in enough water to create a 125-gram solution, what is the solution’s concentration, expressed as a percent by mass?

[removed] 3.6% NaCl

[removed] 3.8% NaCl

[removed] 4.5% NaCl

[removed] 4.7% NaCl

  

Question 3
 (Multiple Choice Worth 2 points)

[06.04]On a potential energy diagram for the following processes, which of the following has a decrease in entropy?

[removed] melting

[removed] freezing

[removed] boiling

[removed] sublimation

  

Question 4
 (Multiple Choice Worth 2 points)

[07.02]Which of the following is the salt in the Brønsted-Lowry neutralization reaction?HBr + NaHCO3  H2CO3 + NaBr

[removed] HBr

[removed] NaHCO3

[removed] H2CO3

[removed] NaBr

  

Question 5
 (Multiple Choice Worth 2 points)

[07.05]Which of the following is not a result when a change to an equilibrium system is applied?

[removed] Increasing the rate of the forward reaction will cause a shift to the left.

[removed] Increasing the rate of the reverse reaction will cause a shift to the left.

[removed] Decreasing the rate of the forward reaction will cause a shift to the left.

[removed] Decreasing the rate of the reverse reaction will cause a shift to the right.

  

Question 6
 (Multiple Choice Worth 2 points)

[08.06]Biotechnology has allowed us to genetically modify corn with a gene that acts as a pesticide. What could be a possible environmental impact of this development?

[removed] Insects resistant to the specific pesticide would develop over time.

[removed] The surplus of corn would rot and decay releasing additional greenhouse gases.

[removed] The price of corn would drop dramatically because of a greater supply with no increase in demand.

[removed] Countries able to buy the new corn seeds would see increases in their economy and pollution would rise.

  

Question 7
 (Multiple Choice Worth 2 points)

[07.05]What would happen if CH4 was removed from the following reaction that has reached equilibrium? CO (g) + 3H2 (g)  CH4 (g) + H2O (g)

[removed] The reaction would not be affected.

[removed] The equilibrium would shift to the right.

[removed] The equilibrium would shift to the left.

[removed] The product concentration would equal the reactants.

  

Question 8
 (Multiple Choice Worth 2 points)

[08.01]If the half-life of Technitium-104 is 18.0min, how much of a 14.2g sample will remain after 72 minutes?

[removed] 3.55g

[removed] 1.78g

[removed] 0.888g

[removed] 0.444g

  

Question 9
 (Multiple Choice Worth 2 points)

[05.07]How many milliliters of a 1.25 molar hydrochloric acid (HCl) solution would be needed to react completely with 60.0 grams of calcium metal?Ca (s) + 2HCl (aq)  CaCl2 (aq) + H2 (g)

[removed] 1200 ml

[removed] 2400 ml

[removed] 3750 ml

[removed] 9600 ml

  

Question 10
 (Multiple Choice Worth 2 points)

[08.01]Which of the following statements is not true of gamma radiation?

[removed] Gamma rays have no mass.

[removed] Gamma rays severely damage living cells.

[removed] Gamma rays are high frequency electromagnetic waves.

[removed] Gamma rays are deflected toward the positive terminal in a magnetic field.

  

Question 11
 (Multiple Choice Worth 2 points)

[06.02]On a potential energy diagram, what is true about activation energy?

[removed] Activation energy is the same for both endothermic and exothermic reactions.

[removed] Activation energy is greater for endothermic reactions.

[removed] Activation energy is greater for exothermic reactions.

[removed] Activation energy is represented by a negative slope.

  

Question 12
 (Multiple Choice Worth 2 points)

[06.05]According to the collision theory and model created to explain the collision theory, why does a catalyst cause a reaction to speed up?

[removed] It lowers the activation energy.

[removed] It increases the collisions per minute.

[removed] It increases the average kinetic energy of the particles.

[removed] It increases the kinetic energy and the collisions per minute.

  

Question 13
 (Multiple Choice Worth 2 points)

[07.02]If it requires 37.5 mL of a 0. 245 M HBr solution to neutralize 18.0 mL Mg(OH)2, what is the concentration of the Mg(OH) 2 solution?2 HBr + Mg(OH) 2  Mg(Br) 2 + 2 H2O

[removed] 0.0120 M

[removed] 0.0255 M

[removed] 0.118 M

[removed] 0.510 M

  

Question 14
 (Multiple Choice Worth 2 points)

[07.06]Which of the following chemical reactions is an oxidation-reduction reaction?

[removed] NO + 2H2  NH3 + H2O

[removed] NaNO3 + LiF  LiNO3 + NaF

[removed] CaSO4 + 2KBr  K2SO4 + CaBr2

[removed] AgNO3 + 2HCl  AgCl + 2HNO3

  

Question 15
 (Multiple Choice Worth 2 points)

[08.03]Heat from the Earth’s core and pressure on the remains of dead plants and animals create which of the following resources?

[removed] biofuel and hydro-electric

[removed] natural gas and coal

[removed] nuclear power and geothermal

[removed] geothermal power and biofuel

  

Question 16
 (Multiple Choice Worth 2 points)

[06.04]On a potential energy diagram, the activation energy is greatest under which of the following conditions?

[removed] The potential energy of the products is greater than the reactants and the change in enthalpy is positive.

[removed] The potential energy of the products is less than the reactants and the change in enthalpy is positive.

[removed] The potential energy of the products is greater than the reactants and the change in enthalpy is negative.

[removed] The potential energy of the products is less than the reactants and the change in enthalpy is negative.

  

Question 17
 (Multiple Choice Worth 2 points)

[06.01]How would a system in which both matter and energy are exchanged freely between the system and the surroundings be classified?

[removed] an open system

[removed] an isolated system

[removed] a closed system

[removed] an integrated system

  

Question 18
 (Multiple Choice Worth 2 points)

[07.06]What is the oxidation number of sulfur (S) in magnesium sulfate (MgSO4)?

[removed] +2

[removed] +3

[removed] +6

[removed] +7

  

Question 19
 (Multiple Choice Worth 2 points)

[06.03]Which substance will require more energy to heat if all the samples have the same mass?

[removed] Lead

[removed] Magnesium

[removed] Iron

[removed] Aluminum

  

Question 20
 (Multiple Choice Worth 2 points)

[05.01]Which of the following describes what occurs as a liquid becomes a solid?

[removed] A physical change occurs; the particles of the liquid vibrate faster and their kinetic energy increases.

[removed] A physical change occurs; the particles of the liquid vibrate more slowly and their kinetic energy decreases.

[removed] A chemical change occurs; the particles of the liquid vibrate faster and their kinetic energy increases.

[removed] A chemical change occurs; the particles of the liquid vibrate more slowly and their kinetic energy decreases.

  

Question 21
 (Multiple Choice Worth 2 points)

[06.03]A 5.45g combustible sample is burned in a calorimeter. The heat generated changes the temperature of 555g water from 20.5°C to 39.5°C. How much energy is released by the burning? The specific heat of water is 4.18 J/ (°C × g).

[removed] 564 J

[removed] 2500 J

[removed] 44100 J

[removed] 138000 J

  

Question 22
 (Multiple Choice Worth 2 points)

[08.02]How can a sample of uranium-235 that has critical mass be induced to react?

[removed] It must be spilt with a laser.

[removed] It must be fused to a helium nucleus.

[removed] It must be bombarded it with neutrons.

[removed] It must be shot with light speed electrons.

  

Question 23
 (Multiple Choice Worth 2 points)

[07.01]What happens when an acid reacts with an active metal?

[removed] A neutralization reaction occurs.

[removed] Hydronium ion concentration is increased.

[removed] Oxygen gas is produced.

[removed] Hydrogen gas is produced.

  

Question 24
 (Multiple Choice Worth 2 points)

[06.05]According to the collision theory and model created to explain the collision theory, what is the best explanation for why a higher temperature makes a reaction go faster?

[removed] There are more collisions per minute.

[removed] It increases the distance between the particles.

[removed] It increases the average kinetic energy of the particles.

[removed] It increases the average kinetic energy and there are more collisions per minute.

  

Question 25
 (Multiple Choice Worth 2 points)

[07.04]Which answer describes a chemical reaction in equilibrium?

[removed] The reactants are all used up.

[removed] All the product is formed.

[removed] The forward and reverse reactions have ceased.

[removed] The forward and reverse reaction rates are the same.

  

Question 26
 (Multiple Choice Worth 2 points)

[08.03]Which of the following best describes the forces that generate geothermal power?

[removed] Heat energy beneath the Earth’s surface heats underground water into steam.

[removed] Heat from the Earth’s core and pressure transform the remains of dead plants and animals.

[removed] Energy of the sun strikes photovoltaic cells producing a flow of electrons.

[removed] Heat energy is released during nuclear fission and steam is produced to turn a turbine.

  

Question 27
 (Multiple Choice Worth 2 points)

[06.04]Which of the following circumstances will result in a reaction that is spontaneous at all temperatures?

[removed] positive enthalpy change and positive entropy change

[removed] negative enthalpy change and negative entropy change

[removed] positive enthalpy change and negative entropy change

[removed] negative enthalpy change and positive entropy change

  

Question 28
 (Multiple Choice Worth 2 points)

[05.06]Water is a polar molecule and attracts other polar molecules. Which of the following is a consequence of this property?

[removed] Water is considered to be a universal solvent.

[removed] Water can only dissolve a limited amount of solute.

[removed] When water freezes, the molecules move farther apart.

[removed] The water in lakes and ponds freezes from the top down.

Question 29
 (Multiple Choice Worth 2 points)

[07.04]What is the correct balanced equation for the following equilibrium constant expression?

[removed] CO2 (g)  CO (g) + ½ O2 (g)

[removed] CO2 (g)  CO (g) + O2 (g)

[removed] 2 CO2 (g)  2 CO (g) + O2 (g)

[removed] 2CO (g) + O2 (g)  CO2 (g)

  

Question 30
 (Multiple Choice Worth 2 points)

[07.06]In the chemical reaction shown below, which element was oxidized?2K + Cl2  2KCl

[removed] K, because it lost one electron

[removed] K, because it gained one electron

[removed] Cl, because it lost one electron

[removed] Cl, because it gained one electron

  

Question 31
 (Multiple Choice Worth 2 points)

[07.01]Which of the following correctly shows a neutralization reaction between a hydronium ion and a hydroxide ion?

[removed] H+ + H2O  H3O+

[removed] H2O  H+ + OH-

[removed] H3O+ + OH-  2 H2O

[removed] H2O + NH3  OH- + NH4+

  

Question 32
 (Multiple Choice Worth 2 points)

[05.03]If 1.20 moles of an ideal gas occupy a volume of 18.2 L at a pressure of 1.80 atm, what is the temperature of the gas, in degrees Celsius?

[removed] -125°C

[removed] 59.5°C

[removed] 273°C

[removed] 332°C

  

Question 33
 (Multiple Choice Worth 2 points)

[08.02] Which describes nuclear power plants?

[removed] They generate power directly from nuclear reactions.

[removed] They supply over 50% of the nation’s power needs.

[removed] Compared to fossil fuels, they require much less fuel.

[removed] They have more atmospheric pollutants compared to fossil fuels.

  

Question 34
 (Multiple Choice Worth 2 points)

[05.08]A student dissolves 4.5 g of sodium chloride (NaCl) into 75 g of water (H2O). Which of the following statements is correct regarding the resulting solution when it is compared to the pure solvent?

[removed] Both the vapor pressure and the boiling point will increase.

[removed] The boiling temperature and the freezing temperature will decrease.

[removed] The freezing temperature will increase and the vapor pressure will decrease.

[removed] The vapor pressure will decrease and the boiling temperature will increase.

  

Question 35
 (Multiple Choice Worth 2 points)

[05.04]When 1.5 L of methane gas combust in an excess of oxygen at standard temperature and pressure, how many liters of water vapor will be produced? CH4 (g) + 2O2 (g)  CO2 (g) + 2H2O (g)

[removed] 0.75 L

[removed] 1.5 L

[removed] 3.0 L

[removed] 6.0 L

  

Question 36
 (Multiple Choice Worth 2 points)

[07.03]Which of the following pH levels would be the most acidic?

[removed] pH 2

[removed] pH 5

[removed] pH 8

[removed] pH 12

  

Question 37
 (Multiple Choice Worth 2 points)

[06.01]If you drop a 25 gram piece of metal that has a temperature of 100° Celsius into 1000 grams of water at 20°Celsius, what best describes what would occur?

[removed] The temperature lost by the metal will equal the temperature gained by the water.

[removed] The heat lost by the metal will equal the heat gained by the water.

[removed] The final temperature will be 60°Celsius.

[removed] The final temperature will be more than 60°Celsius.

  

Question 38
 (Multiple Choice Worth 2 points)

[08.05]Which of the following is not true regarding carbon?

[removed] Carbon 12 is radioactive.

[removed] Carbon can form long chains and rings.

[removed] Carbon will bond with other carbon atoms.

[removed] Carbon will readily bond with hydrogen and oxygen.

  

Question 39
 (Multiple Choice Worth 2 points)

[07.03]What is the pH of a 0.00750 M solution of hydrochloric acid, HCl?

[removed] pH = 1.45

[removed] pH = 1.93

[removed] pH = 2.12

[removed] pH = 3.07

  

Question 40
 (Multiple Choice Worth 2 points)

[05.03]A balloon that contains 0.750 moles of gas has a volume of 16.8 L. If the balloon expands to a volume of 25.4 L at a constant pressure and temperature, how many moles of gas would the balloon contain?

[removed] 0.496 mol

[removed] 0.882 mol

[removed] 1.13 mol

[removed] 6.45 mol

  

Question 41
 (Multiple Choice Worth 2 points)

[08.04]It is widely known that fossil fuels pollute the environment and cause harmful effects. Why then are fossil fuels still being widely used?

[removed] Not enough of society knows the harmful nature of fossil fuels.

[removed] Cost effective alternatives are not yet ready to replace fossil fuels.

[removed] Alternative fuels offer just as many environmental problems as fossil fuels.

[removed] The demand for alternative fuels cannot be met by current manufacturers.

  

Question 42
 (Multiple Choice Worth 2 points)

[05.01]Which phase of matter is made up of particles that are packed relatively close together, with an indefinite shape but a definite volume?

[removed] gas

[removed] liquid

[removed] plasma

[removed] solid

  

Question 43
 (Multiple Choice Worth 2 points)

[05.05]Which of the following would be the best technique to use in order to separate a liquid from a solution?

[removed] chromatography

[removed] evaporation

[removed] filtration

[removed] simple distillation

  

Question 44
 (Multiple Choice Worth 2 points)

[06.02]When sulfuric acid is poured on sugar the volume expands, it turns black and gets very hot. Which of the following best describes this reaction?

[removed] endothermic

[removed] exothermic

[removed] decomposition

[removed] synthesis

  

Question 45
 (Multiple Choice Worth 2 points)

[06.04]Which of the following reactions results in a decrease in entropy?

[removed] 6CO2 (g) + 6H2O (l)  C6H12O6 (s) + 6O2 (g)

[removed] 2NH3 (g)  N2 (g) + 3H2 (g)

[removed] N2O4 (g)  2NO2 (g)

[removed] 2H2O2 (aq)  2H2O (l) + O2 (g)

  

Question 46
 (Multiple Choice Worth 2 points)

[08.05]Carbon naturally occurs in two forms: diamond and graphite. Why do these two forms have very different properties?

[removed] The key difference is that diamonds have other elements bonded within their structure.

[removed] The differences are explained by the number of covalent and ionic bonds within each substance.

[removed] The differences are explained by the density: graphite is very high and diamond is much lower.

[removed] The differences are explained by how the carbon atoms within each substance are covalently bonded together.