Cabarrus County Schools



Unit 6 Test – Energy, Gas Laws, and Specific Heat1.As Nicholas observes the flame of a candle, he sees wax near the flame change from solid to liquid. What happens first to cause this solid to liquid phase change??A.Heat from the flame increases the potential energy of wax molecules.?B.Heat from the flame increases the kinetic energy of wax molecules.?C.Heat from the flame breaks bonds in the wax molecules.?D.Heat from the flame fuses wax atoms into molecules.2.An investigation was conducted using Pure Substance X which was cooled at a constant rate over time. The graph below shows the phase changes of the substance over time as it cooled.According to the curve, how long did it take for Pure Substance X to freeze completely from a liquid to a solid??A.5 minutes?B.10 minutes?C.15 minutes?D.20 minutes3.The physical state of a substance depends on the arrangement of atoms or molecules within it. The diagram shows the arrangement of atoms of the same substance at two different times. At Time 1 the atoms are close together. At Time 2 the atoms are moving apart.Which statement BEST describes the change occurring from Time 1 to Time 2??A.A gas becoming a solid.?B.A gas becoming a liquid.?C.A solid becoming a liquid.?D.A liquid becoming a solid.4.Which phase change occurs during sublimation??A.liquid to solid?B.liquid to gas?C.solid to liquid?D.solid to gas5.Which statement BEST describes the motion of water molecules as the water changes state from steam to liquid??A.The molecules move faster and occupy more space.?B.The molecules move slower and occupy more space.?C.The molecules move faster and occupy less space.?D.The molecules move slower and occupy less space.6.The table shows the melting points and heats of fusion of hydrogen and sulfur.Element MeltingPoint(°C) Heat of Fusion(kilojoulesper kilogram) Hydrogen–259.31 58.6 Sulfur 119 38.1 Based on the table, which statement BEST describes the relative properties of hydrogen and sulfur??A.Liquid sulfur requires less energy to increase in temperature than liquid hydrogen.?B.Solid hydrogen contains more energy than solid sulfur so it melts at a lower temperature.?C.Hydrogen melts at a lower temperature than sulfur but requires more energy to change phase.?D.Sulfur requires less energy to melt because a larger proportion of energy works to raise the temperature.7.This graph represents data collected when a sample of a gas is uniformly cooled from 155°C. Why does the temperature of the sample remain constant between point X and point Y??A.because the sample is transitioning from a gaseous state to a solid state?B.because the sample is transitioning from a gaseous state to a liquid state?C.because the sample is transitioning from a solid state to a gaseous state?D.because the sample is transitioning from a liquid state to a solid state8.A heating curve for 50.0 g of ethanol is shown below.Based on the graph, calculate the heat of fusion for ethanol.?A.67.9 J/g?B.107 J/g?C.367 J/g?D.838 J/g9.How does the amount of heat energy change as a 250-g sample of water is heated from 5.0°C to 30.0°C??A.The amount of heat energy increases, causing the water to sublime.?B.The amount of heat energy increases, causing the water to evaporate.?C.As the temperature increases, the amount of heat energy decreases.?D.As the temperature increases, the amount of heat energy increases.10.The heating curve for methanol is shown below.Based on the graph, how much energy is required to completely evaporate 73 g of methanol??A.7 kJ?B.80 kJ?C.700 kJ?D.80000 kJ11.Use the hydrogen phase diagram to answer the question.What is the boiling point of hydrogen at atmospheric pressure (1.0 × 105 Pa)??A.12 K?B.14 K?C.20 K?D.33 K12.An unknown solid substance is heated according to the temperature versus time graph below.While the substance is a liquid, at what temperature do the molecules of the substance have the greatest average kinetic energy??A.0?C?B.5?C?C.40?C?D.60?C13.The phases of a substance under various pressure and temperature combinations are shown on this phase diagram. What occurs if the pressure of the substance at point F remains constant, and the temperature increases to point G??A.It will transition from a solid state to a liquid state.?B.It will transition from a liquid state to a solid state.?C.It will transition from a solid state to a gaseous state.?D.It will transition from a gaseous state to a solid state.14.The graph shows phase changes for a pure substance when heat is added at a constant rate.During which time interval does a phase change occur while energy is absorbed??A.0–5 minutes?B.10–20 minutes?C.20–35 minutes?D.35–40 minutes15.This phase diagram shows that sulfur (S8) has two solid phases, as well as liquid and gas phases. There are three distinct triple points shown on the diagram.What phases of sulfur exist in equilibrium at a temperature of 119°C and pressure of 0.0001 atmosphere??A.liquid, rhombic solid, and gas?B.gas, liquid, and monoclinic solid?C.gas, rhombic solid, and monoclinic solid?D.liquid, rhombic solid, and monoclinic solid16.A researcher measures the temperature of a hot gas. This observation is used to determine which property of the gas molecules??A.average kinetic energy?B.elastic potential energy?C.movement of thermal energy?D.transformation of chemical energy17.How many grams of methane gas occupy a volume of 11.2 liters at STP??A.6.51 grams?B.8.03 grams?C.26.0 grams?D.32.1 grams18.The normal pressure for a car tire is 220 kPa. The actual pressure reading for a tire is 262 kPa. Which of the following BEST explains why the actual pressure is greater than normal??A.An increase in molecules of gas produces fewer collisions against the inner tire surface.?B.More collisions occur between the inner surface of the tire as gas molecule numbers increase.?C.Random motion of gas molecules increases due to a decrease in the number of gas molecules.?D.A change in the number of gas molecules in the tire causes the random motion to be unstable.19.Which of these changes will increase the vapor pressure of water in a sealed container??A.Add more water and reseal the container.?B.Shake the container vigorously and let the water settle.?C.Add salt to the water and reseal the container.?D.Increase the temperature of the water in the container.20.A student places a balloon filled with helium gas into a freezer and thirty minutes later observes that the balloon shrank. Which statement describes why the balloon changed in size??A.The number of helium atoms decreased.?B.The average kinetic energy of atoms decreased.?C.The total heat of atoms increased.?D.The heat capacity of atoms increased.21.Which set shows the physical states of water, H2O, in order according to the increasing energy of particle motion??A.H2O (s) , H2O (g), H2O (l)?B.H2O (g), H2O (s), H2O (l)?C.H2O (l), H2O (s), H2O (g)?D.H2O (s), H2O (l), H2O (g)22.A heating curve for water is shown.What is occurring to the water at the segment of the graph between points C and D??A.melting?B.condensing?C.absorbing energy?D.increasing in temperature23.A substance is heated at a constant rate, and the temperature is recorded over time. A graph of the data is shown.Which statement BEST describes why the temperature remains constant during certain time intervals??A.Heat is not distributed evenly throughout the substance.?B.Energy is required to change the phase of the substance.?C.Electrons in the atoms are set free at certain temperatures.?D.Energy levels in the atoms absorb energy in specific amounts.24.Which statement BEST describes the relationship between temperature and kinetic energy of particles??A.Temperature increases as kinetic energy of particles increases.?B.Kinetic energy of particles increases as temperature decreases.?C.Kinetic energy of particles remains constant as temperature changes.?D.Temperature remains constant as kinetic energy of particles changes.25.An ice cube is initially at a temperature of –20 °C. Heat is added, causing the ice to change phases, first melting to water and then changing to steam. The diagram shows the changes in temperature as heat is added to the system.Which statement below is true??A.As heat is added in Stage 2 the temperature of the ice cube increases to 0 °C.?B.As heat is added in Stage 3 the temperature of the water increases from 0 to 100 °C.?C.As heat is added in Stage 4 the temperature is constant and the ice cube melts to form water.?D.As heat is added in Stage 5 the water that was in the ice cube is transformed into water vapor.26.The graph below represents data collected during a laboratory investigation on the phase changes of water.Which can be concluded from the graph??A.From time G to H, heat energy was absorbed.?B.From time H to I, the water changed from a gas to a solid.?C.From time J to K, heat energy remained the same.?D.From time K to L, the water changed from a solid to a liquid.27.The graph illustrates the process of changing ice at –50°C to steam at 150°C.Which segment of the graph represents the largest absorption of energy by the water molecules??A.1?B.2?C.3?D.428.Examine the phase diagram of carbon dioxide.What is the triple point of carbon dioxide? ?A.1 atm, –78.5°C?B.5.11 atm, –56.4°C?C.73.0 atm, –56.4°C?D.73.0 atm, 31.1°C29.An investigation was conducted on a pure substance to determine at what temperatures it underwent phase changes. The graph shows the phase changes of the pure substance as it was heated at a constant rate.The investigator used one of the following substances in this experiment.Melting and Boiling Points of Four SubstancesSubstanceMelting Point (°C)Boiling Point (°C)120100240140370140480160Which of these substances was used in this phase change investigation??A.Substance 1?B.Substance 2?C.Substance 3?D.Substance 430.According to the phase diagram below, a sample of water exists in two phases at a pressure of 1 atm and a temperature of 0°C.What will happen to the sample if the pressure is increased to 10 atm at the same temperature??A.Ice will change to liquid water.?B.Liquid water will change to ice.?C.Ice will change to water vapor.?D.Liquid water will change to water vapor.31.In an experiment, a scientist burned 10.0 g of methane, and the temperature of the 500.0 mL of water in the calorimeter changed from 21.0°C to 26.6°C. The specific heat of water is 4.18 J/g·°C. How much energy was released in joules??A.?B.?C.?D.32.How much energy is needed to raise the temperature of 5.0 grams of lead from 25°C to 35°C? [specific heat (c) = 0.129 J/(g?°C)]?A.6.45 J/(g?°C)?B.6.45 J?C.16.1 J/(g?°C)?D.16.1 J33.When a student uses the equation, mass multiplied by change in temperature multiplied by specific heat, what is being calculated??A.a phase change?B.stored energy?C.heat convection?D.heat gain or heat loss34.When a piece of metal was heated in a flame and then dropped into a foam cup calorimeter filled with 200 mL of water at 22.5°C, the temperature of the water rose to 38.7°C. How much heat was transferred from the metal to the water? The specific heat of water is 4.18 J/g?°C?A.13.5 kJ ?B.18.8 kJ?C.23.7 kJ?D.32.3 kJ35.During the combustion of 2.00 g of coal, the temperature of 500 g of water inside the calorimeter increased from 25.0°C to 43.7°C. The specific heat of water is 4.18 J/g·°C. How much heat did the reaction generate? ?A.19,500 J?B.39,100 J?C.45,700 J?D.91,300 J36.The total pressure of a gas mixture is 1.05 atm. The mixture contains 55% carbon dioxide, 31% nitrogen, and 14% hydrogen. What is the partial pressure of the carbon dioxide in the mixture??A.0.15 atm?B.0.33 atm?C.0.47 atm?D.0.58 atm37.At the top of Mount Everest, water boils at about 72°C, which is 28°C lower than the boiling point at sea level. Why is the boiling point of water lower at the top of the mountain??A.Air pressure on the mountain is lower, which increases the vapor pressure of water.?B.The vapor pressure of water exceeds the air pressure at a lower temperature on the mountain.?C.Water absorbs heat more efficiently at higher elevations due to lower atmospheric pressure.?D.The lower atmospheric pressure reduces the intermolecular forces among water molecules.38.A sample of carbon dioxide has a pressure of 1.2 atm, a volume of 50.0 L, and a temperature of 650K. How many moles of carbon dioxide are included in the sample? (Ideal gas law: , )?A.0.1 mol?B.0.9 mol?C.1.1 mol?D.2.6 mol39.A sample of 0.800 mol of nitrogen has a pressure of 0.600 atm and a volume of 30.0 L. What is its temperature? (Ideal gas law: , )?A.22.5K?B.219K?C.274K?D.343K40.A sample of 0.500 mol of hydrogen has a pressure of 3.00 atm and a temperature of 799K. What is its volume? (Ideal gas law: , )?A.10.9 L?B.32.8 L?C.73.2 L?D.98.4 L ................
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