Review the information in this week’s Learning Resources dealing with variance analysis
July 12, 2019
The difference between the present value of an investment?s future cash flows and its initial cost
July 12, 2019

chemistry

Question 1 (Multiple Choice Worth 2 points)
[08.04]<object:standard:sc.912.l.17.15>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]<object:standard:sc.912.p.10.6>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]<object:standard:sc.912.p.8.8, sc.912.p.8.11=””>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]<object:standard:sc.912.p.12.13>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]<object:standard:sc.912. l.16.10=””>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]<object:standard:sc.912.p.12.13>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]<object:standard:sc.912.p.10.11, sc.912.p.10.12=””>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]<object:standard:sc.912. p.8.9.=””>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]<object:standard:sc.912.p.10.11, sc.912.p.10.12=””>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]<object:standard:sc.912.p.10.6>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]<object:standard:sc.912.n.3.5, sc.912.p.12.12=””>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]<object:standard:sc.912.p.8.8, sc.912.p.8.11=””>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]<object:standard:sc.912.p.8.8>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]<object:standard:sc.912. l.17.19=””>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]<object:standard:sc.912.p.10.6>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]<object:standard:sc.912.p.10.2>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]<object:standard:sc.912.p.8.10>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]<object:standard:sc.912.p.10.5>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]<object:standard:sc.912.p.8.1, sc.912.p.8.2=””>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]<object:standard:sc.912.p.10.2, sc.912.p.10.5=””>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]<object:standard:sc.912.p.10.11>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]<object:standard:sc.912.p.8.11>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]<object:standard:sc.912.n.3.5, sc.912.p.12.12=””>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]<object:standard:sc.912.p.12.13>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]<object:standard:sc.912. l.17.19=””>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]<object:standard:sc.912.p.10.2>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]<object:standard:sc.912.l.18.12>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]<object:standard:sc.912.p.12.13>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]<object:standard:sc.912.p.8.10>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]<object:standard:sc.912.p.8.11>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]<object:standard:sc.912.p.12.10>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]<object:standard:sc.912.p.10.11> 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]<object:standard:sc.912.p.8.2.>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]<object:standard:sc.912.p.12.10, sc.912.p.8.9=””>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]<object:standard:sc.912.p.8.11>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]<object:standard:sc.912.p.10.2>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]<object:standard:sc.912.p.8.12>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]<object:standard:sc.912.p.8.11>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]<object:standard:sc.912.p.12.10>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]<object:standard:sc.912.n.4.2>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]<object:standard:sc.912.p.8.1>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]<object:standard:sc.912.p.10.7>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]<object:standard:sc.912.p.10.2>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]<object:standard:sc.912.p.8.12>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.

 

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