Critical Thinking

In which of the following reaction mixtures, where A reacts with B in the following balanced equation, is B the limiting reactant? A+2B-> ΑΒ 2

A

Which picture model best represents the physical change of evaporating or boiling water?

A is wrong, C is wrong, D is wrong, b

Water has a density of 1.00 g/cm3. Given the data in the table, which material would sink in water (assume no dissolving)? A B C More than one

c

In what state is methanol at room temperature (about 25 ˚C)? a.gas b.liquid c.solid

liquid

When a solid metal object is heated, its volume increases. In terms of what is happening at the nanoscopic scale, this volume increase is evidence that: The size of the particles of the metal is increasing The distances between the particles of the metal are increasing The mass of the particles of the metal is increasing The sizes of the particles are increasing, along with the distances between them.

The sizes of the particles are increasing, along with the distances between them. is wrong, The distances between the particles of the metal are increasing

Fe 2O 3( s) and powdered aluminum (Al) can react with great output of heat to form molten iron (Fe) and Al 2O 3. When this reaction equation is balanced, what are the coefficients in the following order: Fe 2O3, Al, Fe, Al 2O 3? a. 1, 1, 1, 1 b. 2, 1, 1, 2 c. 1, 2, 2, 1 d. 2, 2, 2, 2 e. 1, 1, 2, 2

1,2,2,1

Which one of the following statements is not correct? a.Liquid water turning into steam is a chemical reaction. b.Methanol burning is a chemical reaction .c.Bleaching your hair is a chemical change (reaction), even though it changes your physical appearance. d.Sugar dissolving in water is a physical change. e.Dry ice subliming is a physical change.

A. Liquid water turning into steam is a chemical reaction.

Consider the following three quantities that can be used in describing a gas: Temperature, volume, average kinetic energy of the particles. Which of these three quantities (if any) can be observed (measured) directly and don't depend on the small particle theory? Temperature only Volume only Average particle kinetic energy only Temperature and volume only Temperature and average particle kinetic energy only

Temp and volume only

A solid forming a liquid is called

melting

The table below summarizes some of the physical properties of three different materials. Given the data in the table, which material is a liquid at room temperature (20°C)?

C is wrong more then one is wrong,

Two closed containers with movable tops contain two different gases at room temperature (about 25 °C). Container A contains 1 liter of Gas A. Container B contains 1 liter of Gas B, which has a density that is twice that of Gas A. Both containers are then slowly heated to 100 °C. During heating, the tops move upward as the gases expand, but they do not come off. They stop moving when the heating ends.After the gases have been heated to 100 °C, which of the following statements is true? Gas A and Gas B have the same volume, but different pressures and densities. Gas A and Gas B have the same pressure and density, but different volumes Gas A and Gas B have the same pressure, but different volumes and densities Gas A and Gas B have the same pressure and volume, but different densities.

Gas A and Gas B have the same pressure and volume, but different densities.

For three different materials at room temperature—one is a gas, one is a liquid and the other a solid—how do the average kinetic energies of the particles compare? ( < is less than, = is equal to, > is greater than) a.Solid = liquid = gasb.Solid > liquid > gasc.Solid < liquid < gas a. Solid = liquid = gas b. Solid > liquid > gas c. Solid < liquid < gas

Solid = liquid = gas

For three different materials at room temperature—one is a gas, one is a liquid and the other a solid—how would you rank the strength of attractive forces between particles for these materials? ( < is less than, = is equal to, > is greater than) a.Solid = liquid = gas b.Solid > liquid > gas c.Solid < liquid < gas

Solid > liquid > gas

Given the melting and boiling points of water (0 ˚C and 100 ˚C) and methanol (-98 ˚C and 67 ˚C), how do the strength of attractive forces between particles compare? a.The attractive forces of methanol and water are equal .b.The attractive forces of methanol are stronger than the attractive forces of water. c.The attractive forces of methanol are weaker than the attractive forces of water.

The attractive forces of methanol are weaker than the attractive forces of water.

Imagine you are using the gas simulation with fixed walls. Suppose you replaced the gas cylinder with a vacuum pump. When the simulation runs, the pump removes gas from the cylinder at a constant rate.For this situation, you would find that the density of the gas decreases while the vacuum pump is operating. What is the best explanation for this? a.The mass of gas remains the same and the volume increases. b.The mass of gas remains the same and the volume decreases. c.The mass of gas increases and the volume remains the same. d.The mass of gas decreases and the volume increases. e.The mass of gas decreases and the volume remains the same.

The mass of gas decreases and the volume remains the same.

When water freezes, liquid water turns to solid ice mainly because a.The molecules move slowly enough that their attractions keep them in fixed positions b.Ice can float on water c.All liquid water eventually becomes iced. d. The water molecules get harder

The molecules move slowly enough that their attractions keep them in fixed positions

A hypothesis is

an explanation of observed processes that needs to be tested.

Suppose you have a container of air that has a movable top. Assume you then slowly push the top of the container downward, thereby decreasing the volume of the container, but keeping the temperature constant. No gas enters or leaves the system as you push the top downward. What would happen to the pressure of the air? increase Decrease remain the same Can't be determined without more information

increase

Energy that an object has by virtue of its motion is called ________ a.orbital energy. b.potential energy. c.thermal energy. d.mechanical energy. e.kinetic energy.

kinetic

Which of the following variables must be held constant if you are testing the relationship between the pressure of a gas and its temperature? (Choose all that apply.) pressure number of particles volume temperature

pressure number of particles volume temperature ALL 4

Suppose you have a container of air that has a movable top. Assume you then slowly lift the top of the container upward, thereby increasing the volume of the container, but keeping the temperature constant. No gas enters or leaves the system as you pull the top upward. What would happen to the kinetic energy?

remain the same

When you place a piece of dry ice (solid carbon dioxide) on a plate at room temperature, you notice term-0that no liquid forms, unlike ice that melts to form liquid water. This is because dry ice ________

sublimes instead of melting.

Which one of the following is not a chemical reaction? a.wood burning b.iron rusting c.eggs cooking d.dynamite exploding e.water turning to steam

water turning to steam

A glass of cold milk sometimes forms a coat of water on the outside of the glass (often referred to as "sweat".) How does most of the water get there? Water evaporates from the milk and condenses on the outside of the glass. The glass acts like a semipermeable membrane and allows the water to pass, but not the milk. Water vapor condenses from the air The coldness causes oxygen and hydrogen from the air to combine on the glass forming water.

water vapor condenses from the air

Mixture 2 contained lentils, pepper and salt. Choose the option below that puts these tools in the correct order to separate the components. Note that one or more tools may not be needed for this mixture. screen, water , coffee filter, evaporation dish water, coffee filter, evaporation dish, screen water, screen, coffee filter, evaporation dish water, coffee filter, screen, evaporation dish screen, magnet, water, evaporation dish, coffee filter

water, screen, coffee filter, evaporation dish

At the Tesla automotive factory, a Model S sedan is built using 4 tires, a main chassis, and 5 lithium ion batteries. How many sedans can be made if there are 17 tires, 5 chassis, and 22 batteries?

4

If the heating curve shown is for ethanol (melting point -117.0 °C; boiling point 78.0 °C), what temperature is represented by line D on the heating curve?

78

If the heating curve shown is for ethanol (melting point -117.0 °C; boiling point 78.0 °C), what temperature is represented by line B on the heating curve? -117 C 0 C 78 C 100 C

78 next wrong

Which of the following cartoons depict a balanced reaction?

B

Which of the following samples of an ideal gas has the lowest density? a. b. c. d.

C

Which of the following cartoons depict a balanced reaction?

C wrong d

Which diagram depicts the process of freezing? The asterick represents the final state.

E is wrong D is wrong

Which model represents a gaseous element?

Model A

Which of the following best describes the relationship between pressure, temperature and volume of a gas, assuming the number of particles remains constant?

PV = constant * T

Consider the following three different pressure vs time graphs generated from a simulator.

graph 3

Which of the following graphs shows a direct proportionality?

graph a

A cooling curve for some substance is shown below. Which of the line segments (I-V) represents the liquid-to-solid transition?

IV

If you had equal masses of each of the following substances, which would occupy the greatest volume? a.beeswax (d 0.960 g/mL) b.water (d 0.997 g/mL) c.cocoa butter (d 0.910 g/mL) d.aluminum (d 2.70 g/mL) e.ice (d 0.917 g/mL)

cocoa butter

A gas forming a liquid is called ________ a.freezing.b.condensation.c.vaporization.d.melting.e.deposition.

condensation

Beryllium metal reacts with chlorine gas to produce beryllium chloride (BeCl 2). Given the following diagram of available beryllium atoms and chlorine molecules in a reaction flask, identify the excess reagent and how many atoms/molecules of reactant remain at the end of the reaction. a.Excess reagent: chlorine; Molecules remaining: one b.Excess reagent: beryllium; Atoms remaining: one c.Excess reagent: beryllium; Atoms remaining: two d.Excess reagent: chlorine; Molecules remaining: two e.There is no excess reagent in this reaction.

Excess reagent: beryllium; Atoms remaining: one

When water evaporates a.The water increases in mass' b.the motion of water molecules causes them to stay in the liquid c.Water molecules separate into one oxygen atom and two individual hydrogen atoms d.The motion of water molecules causes them to leave the liquid and become a gas

The motion of water molecules causes them to leave the liquid and become a gas

Mixture 1 contained iron filings, sand and salt. Choose the option below that puts these tools in the correct order to separate the components. Note that one or more tools may not be needed for this mixture. water, screen, evaporation dish, magnet magnet, water, coffee filter, evaporation dish magnet, screen, water, coffee filter, evaporation dish water, coffee filter, magnet, evaporation dish screen, magnet, water, evaporation dish

magnet, screen, water, coffee filter, evaporation dish wrong! water, coffee filter, magnet, evaporation dish wrong screen, magnet, water, evaporation dish

Mixture 3 contained safety pins, beads and glitter. Choose the option below that puts these tools in the correct order to separate the components. Note that one or more tools may not be needed for this mixture. magnet, water , screen , coffee filter magnet, water, screen, evaporation dish water , screen, coffee filter, magnet water, screen, magnet, evaporation dish

magnet, water , screen , coffee filter

Which of the following is NOT a way that matter changes phase? a.freezing b.mixing c.melting d.evaporation

mixing

Which one of the following is not a physical process or change? a.iodine vaporizing b.natural gas burning c.water boiling d.alcohol evaporating e.ice melting

natural gas

What change of state is represented by the following diagram? a.melting b.vaporization c.condensation d.sublimation e.freezing

melting wrong

A heating curve for some substance is shown below. Which of the line segments (I-V) represents heating of the liquid?

III

A scientist collected the following data for ethanol: i. The melting point of ethanol is -114 °C; the boiling point of ethanol is 78 °C. ii. It takes more than twice the amount of heat (twice as much time) to raise the temperature of liquid ethanol by one degree than it does to raise the temperature of an equal mass of either solid or gaseous ethanol by one degree. iii. Boiling liquid ethanol requires more than twice as much heat (twice as much time) than melting the same mass of solid ethanol. The graphs that best represents ethanol is A B C D

A

Imagine you are using the gas simulation with fixed walls. Suppose you replaced the gas cylinder with a vacuum pump. When the simulation runs, the pump removes gas from the cylinder at a constant rate. Assume a # particles meter is attached to the Ultrascope. Which of the following graphs do you think best represents what the # particles (within the Ultrascope view) versus time graph would look like?

A

Given the data, which material is a gas at room temperature (20°C)?

B

In which picture model is mass NOT conserved? A B C D E

E

what would the magnified view show after evaporation

E

Which diagram shown below represents condensation (an asterisk denotes the initial phase of the substance)?

E gas -> liquid, solid

An unknown solid substance has a uniform appearance. Subjecting the substance to either strong heating or a strong electric current does not cause the substance's characteristic properties to change (although, in the case of heating, the state—gas, liquid, or solid—may change), nor does it produce any new substances. What is this substance?

ELEMENT

Which statement about the following chemical reaction is not correct? 2H+2 O2-> 2H2O a. For every two hydrogen molecules consumed, two water molecules are produced. b. Four hydrogen atoms combine with two oxygen atoms to produce two water molecules. c. Two hydrogen molecules react with one oxygen molecule. d. Four hydrogen molecules react with oxygen to produce two water molecules. e. For every oxygen molecule consumed, two water molecules are produced.

. Four hydrogen molecules react with oxygen to produce two water molecules.

Three metals, and their densities, are shown below. If each were added to the same volume of water (density 1.00 cm 3), which metal(s) would sink? a.3 only b.1 and 3 only c.1 only d.2 only e.1 and 2 only

1 and 3 only

At Sal's Sandwich Shop, a regular club sub is made using 2 slices of bread, 3 pieces of meat, and 1 cheese slice. How many club sandwiches can be made if there are 7 slices of bread, 10 pieces of meat, and 5 cheese slices? a.6 b.3 c.4 d.2 e.5

3

#1: A 2-liter plastic bottle of Diet Coke contains lots of small bubbles (carbon dioxide gas) and the soda tastes 'carbonated.' The top is left off for two days and afterwards you notice there are very few bubbles and it tastes 'flat.' #2: Electric current is applied to water resulting in the formation of oxygen gas and hydrogen gas bubbles (this process is called electrolysis). Which of these events are physical changes and which are chemical reactions? a. #1 is a physical change and #2 is a chemical reaction. b. #1 is a chemical change and #2 is a physical change. c. Both #1 and #2 are physical changes. d. Both #1 and #2 are chemical reactions.

A

Which of the following statements correctly describes the properties of a liquid? a.A liquid contains molecules that are separated from one another by large distances.b.A liquid occupies the entire volume of its container.c.A liquid is highly compressible.d.A liquid is highly ordered, such that molecules remain rigidly in place.e.A liquid does not have a definite shape.

A liquid does not have a definite shape.

Four containers, each with the same volume and at the same temperature, are shown in the following diagrams. Which container is at the highest pressure? a. b .c .d.

B

Which model represents a homogenous mixture (solution) of a compound and an element?

B

Which of the following figures is the most accurate representation of a gas sample? The arrows show the velocities of individual molecules.

B

Which of the following lines on the heating curve does NOT represent the warming of a single state? A B C E

B

Consider the following two events: #1: A metal is exposed to a certain gas. After a while, the surface of the metal begins to change color. #2: A mixture contains two solid substances, one of which is ferromagnetic. The mixture is heated. After heating, the mixture has changed color and no longer interacts with a magnet. Which of these events are physical changes and which are chemical reactions? #1 is a physical change and #2 is a chemical reaction. #1 is a chemical change and #2 is a physical change. Both #1 and #2 are physical changes. Both #1 and #2 are chemical reactions

Both #1 and #2 are chemical reactions

Suppose you have a container with a mixture of two gases. The container is heated to a certain temperature. Below are histograms showing the range of speeds of the two types of particles in the mixture.How do the kinetic energies of the two types of particles compare a.both have the same kinetic energy b.type 1 has greater kinetic energy c.2 has greater kinetic energy d.this diagram does not give enough information to make a decision about kinetic energy

Both have the same kinetic energy

Consider a container with fixed walls. An experiment is performed in which the temperature of the container is changed. Above is a graph of the temperature vs. time for the gas in the container. During this same time period, which one of the following graphs would best represent the average kinetic energy of the particles in the container vs. time? A B C D

C

The following models represent the particles of five different chemical systems at room temperature. Assume that each sphere represents an atom, with different colored spheres representing atoms of different elements.Which model represents a liquid compound?

C

Which picture model best represents the chemical change of electrolysis, that is, the separation of water into its component, gaseous elements?

C

Suppose you have a container of air that has a movable top. Assume you then slowly lift the top of the container upward, thereby increasing the volume of the container, but keeping the temperature constant. No gas enters or leaves the system as you pull the top upward. What would happen to the pressure of the air? increase decrease remain the same can't be determined without more information

DECREASE

Which statement about the combustion of propane (C 3H 8) is not correct? C 3H +85O-> 23CO 2+4H 2O a.For every five molecules of oxygen consumed, four molecules of water are produced. b.For every two molecules of propane consumed, eight molecules of water are produced. c.For every three molecules of carbon dioxide produced, five molecules of oxygen are consumed. d.For every propane molecule consumed, three molecules of carbon dioxide are produced. e.For every carbon dioxide molecule produced, four molecules of water are also produced.

For every two molecules of propane consumed, eight molecules of water are produced. is wrong .For every five molecules of oxygen consumed, four molecules of water are produced wrong, b.For every three molecules of carbon dioxide produced, five molecules of oxygen are consumed. is wrong For every propane molecule consumed, three molecules of carbon dioxide are produced.wrong

Which statement A-D about the reaction of methane with oxygen, which is called combustion and is represented by the reaction equation below, is not correct? The reaction products are carbon dioxide and water. CH 4+2O 2-> CO 2 +2H 2O a.One molecule of methane combines with two molecules of oxygen. b.The products are one molecule of carbon dioxide and two molecules of water. c.The equation is balanced because the number of atoms of each element does not change. d.Four atoms of hydrogen combine with four atoms of oxygen to produce water. e.Statements A-D all are correct.

Four atoms of hydrogen combine with four atoms of oxygen to produce water.

Which one of the following statements is not a description of the small particle theory? a.The average kinetic energy of a gas molecule is directly proportional to the absolute temperature of the gas. b.Gas molecules move constantly and randomly throughout the space they occupy. c.The size of a molecule is negligible. d.Gas molecules attract and repel each other. e.Collisions of gas molecules with each other and with the walls of the container are elastic.

Gas molecules attract and repel each other.

Consider a material that is being heated for a certain period of time. During that time energy is transferred into the system and the potential energy of the system of particles increases. The average KE of the particles, however, does not change during this time period. Which of the following processes could this describe? Heating the material during the melting process. Heating the material while it remains in its liquid state. Heating the material during the boiling process Heating the material during either the melting or boiling process (choices A and C). Heating the material while it remains in its vapor state

Heating the material during either the melting or boiling process (choices A and C).

The heating curve for a substance is shown below. The substance initially is a solid. It then becomes a liquid and a gas. Which of the line segments (I-V) represents the solid-to-liquid phase transition? a.IV b.I c.V d.II e.III

II

Italian salad dressing is a mixture of vinegar (density = 1.00 g/ml) and oil (density = 0.92 g/mL). When the mixture stands undisturbed for a period of time, the vinegar and oil separate into distinct layers according to their densities. Suppose you then dropped a chunk of candle wax (density = 0.95 g/mL) into the separated salad dressing. Where would the candle wax settle

It would settle in between the oil and vinegar, with the oil above it and the vinegar below it.

Estimate the melting point and boiling point for methanol from the heating curve. a. Melting point -98 ˚C, Boiling point 67 ˚C b. Melting point 0 ˚C, Boiling point 100 ˚C c. Melting point -120 ˚C, Boiling point 120 ˚C

Melting point -98 ˚C, Boiling point 67 ˚C

In class you observed a movie of a brass sphere passes through a brass ring. If the brass ring were then placed in liquid nitrogen and cooled to about -80oC, the sphere would no longer pass through the ring. You would infer that the brass ring was involved in thermal contraction. Below, to the upper left, is a particle-level (microscopic) model of the brass at room temperature (20oC). Circle the model (A, B or C) that could best represent a model of the brass -80oC?

Model A

Hot water evaporates faster than room temperature water. This is mainly because: a.More water molecules move fast enough to break away from other water molecules b.Room temperature water has more mass c.The molecules in room temperature water are moving faster d.Molecules of hot water are lighter

More water molecules move fast enough to break away from other water molecules

Suppose you have a container of air that has a movable top. Assume you then slowly lift the top of the container upward, thereby increasing the volume of the container, but keeping the temperature constant. No gas enters or leaves the system as you pull the top upward. Now suppose you release the top. Would the top of the container be subject to a net force directed upward or downward? Why? Neither. The forces on the top would balance because the air pressure outside the container is equal to the air pressure inside the container. Downward, because the air pressure outside the container is greater than the air pressure inside the container. Upward, because the air pressure inside the container is greater than the air pressure outside the container. Can't be determined without more information

Neither. The forces on the top would balance because the air pressure outside the container is equal to the air pressure inside the container is wrong, Upward, because the air pressure inside the container is greater than the air pressure outside the container. is wrong Can't be determined without more information

Which of the following statements are common to the small particle models of gases and liquids? I. The space between particles is, on average, very large compared to particle size. II. Particles are in constant motion and move freely in all directions. III. Particles change speed and direction through collisions with other particles. IV. There are strong attractive forces between particles. V. The average kinetic energy of particles is proportional to the temperature of the material.

Statements I, IV, and V

Which of the following statements are common to the small particle models of gases and solids? I. The space between particles is, on average, comparable to particle size. II. Particles are in constant motion. III. Particles collide with a strong attraction between particles. IV. The average kinetic energy of particles is proportional to the temperature of the material. V. The pressure exerted by the material in a container of fixed volume is proportional to the average kinetic energy of the particles. Statements II and IV Statements II, III, and IV Statements I, II, IV, and V Statements I, III, and IV

Statements II, III, and IV

At room temperature both water and ethanol are liquids, but at 90 °C, water is still liquid and ethanol is a gas. What does this suggest about the attractive forces between particles of ethanol in comparison to those of water? The attractive forces between ethanol particles are stronger than the attractive forces between water particles. The attractive forces between ethanol particles are weaker than the attractive forces between water particles. The attractive forces between ethanol particles are about the same as the attractive forces between water particles. The attractive forces between ethanol particles can't be compared to the attractive forces between water particles.

The attractive forces between ethanol particles are weaker than the attractive forces between water particles.

A glass jar contains a mixture of two different gases, G and H. The particles of gas G are three times the mass the particles of gas P. The jar is heated so that its temperature increases by 33 degrees Celsius. At this new temperature, how do the average kinetic energies of the particles of the two gases compare with each other? The average kinetic energies are the same The average kinetic energy of G is greater than the average kinetic energy of H The average kinetic energy of G is less than the average kinetic energy of H The average kinetic energies can't be compared without more information.

The average kinetic energies are the same

A glass jar contains a mixture of two different gases, Q and P. The particles of gas Q have one-half the mass of the particles of gas P. The jar is cooled so that its temperature decreases by 10 degrees Celsius. At this new temperature, how do the average speeds of the particles of the two gases compare with each other? The average speed of particles of gas P is the same as the average speed of particles of gas Q. The average speed of particles of gas P is greater than the average speed of particles of gas Q. The average speed of particles of gas P is less than the average speed of particles of gas Q. The average speed of particles of gas P can't be compared to the average speed of particles of gas Q without more information.

The average speed of particles of gas P is greater than the average speed of particles of gas Q. wrong

A glass jar contains a mixture of two different gases, X and Y. The particles of gas X have eight times the mass of the particles of gas Y. The jar is heated so that its temperature increases by 40 degrees Celsius. At this new temperature, how do the average speeds of the particles of the two gases compare with each other? The average speed of particles of gas X is greater than the average speed of particles of gas Y. The average speed of particles of gas X is less than the average speed of particles of gas Y. The average speed of particles of gas X is the same as the average speed of particles of gas Y. The average speed of particles of gas X can't be compared to the average speed of particles of gas Y without more information

The average speed of particles of gas X is less than the average speed of particles of gas Y.

If you compare ice and liquid water on the molecular level, you could say that a.The molecules in liquid water are smaller b.The molecules in liquid water are closer together c.The molecules in ice are closer together d.The molecules in ice slide past each other

The molecules in ice are closer together

Which statement about the properties of a gas is not correct? a.When the pressure is changed, the volume of a gas changes much more than the volume of a solid or liquid. b.When the temperature is changed, the volume of gas changes much more than the volume of a solid or liquid. c.The density of a gas typically is much larger than the density of a solid or liquid. d.Unlike a solid or a liquid, gases expand to occupy the entire volume of their container.

The density of a gas typically is much larger than the density of a solid or liquid

A closed container contains a mixture of two gases. One gas consists of particles of Type A, and the other, of particles of Type B. Suppose the container is heated so that the mixture's temperature increases by 100 degrees Celsius. Below are histograms showing the range of speeds of the two types of particles in the mixture after the heating has occurred. Assume that there are approximately equal numbers of both types of particles. Which gas contributes more to the pressure exerted on the walls of the container by the gas mixture? Why? The gas is composed of Type A particles because Type A particles are heavier that Type B particles. The gas is composed of Type B particles because Type B particles are faster on average than Type A particles Both gases contribute equally to the pressure exerted by the gas mixture, because the average kinetic energies of Type A and Type B particles are the same. The gas is composed of Type B particles because Type B particles are both heavier and faster (on average) than Type A particles.

The gas is composed of Type B particles because Type B particles are faster on average than Type A particles is wrong Both gases contribute equally to the pressure exerted by the gas mixture, because the average kinetic energies of Type A and Type B particles are the same. The gas is composed of Type B particles because Type B particles are both heavier and faster (on average) than Type A particles.

A clean steel wool pad has a mass of 4 grams. It then rusts when exposed to oxygen in air. After rusting, the rusted steel wool pad will have a mass: The mass will be less than 4 grams The mass will be greater than 4 grams The mass will remain 4 grams The mass could be greater or less than 4 grams

The mass will be greater than 4 gram

Consider two materials, X and Y. The particles of X have a relatively low strength of attraction between them, while the particles of Y have a relatively high strength of attraction between them. How would you expect the melting points of materials X and Y to compare? The melting point of X is higher than the melting point of Y. The melting point of X is lower than the melting point of Y. The melting point of X is the same as the melting point of Y. The melting point of X cant' be compared to the melting point of Y.

The melting point of X is lower than the melting point of Y

A cooling curve for some substance is shown below. Which of the line segments (I-V) represents the gas-to-liquid transition?

V is wrong, IV

Suppose you have a container with a mixture of two gases. The particles of one gas are more massive than the particles of the other gas. The container is heated to a certain temperature. Below are histograms showing the range of speeds of the two types of particles in the mixture.How do the masses of the two types of particles compare? a.type 1 are more massive b.type 2 are more massive c.this diagram does not give enough information to make a decision about mass d.both have the same mass

a.type 1 are more massive

According to the graph, how much energy is needed to boil methanol, as compared to the energy required to melt the same amount of methanol? Assume the rate of heating is constant over time. a.approximately the same amount b.approximately five times more c.approximately ten times more

approx. ten times more

Temperature is the measure of heat potential energy average kinetic energy all of the above

average kinetic energy

Which statement A-D about the reaction of nitrogen monoxide with oxygen, which is called combustion and is represented below by the following cartoon, is not correct? The reaction product is nitrogen dioxide. a.Two molecules of nitrogen monoxide combine with one molecule of oxygen.b.Two atoms of nitrogen combine with four atoms of oxygen to produce two molecules of nitrogen dioxide.c.The equation is balanced because the number of atoms of each element does not change.d.The products are two molecules of nitrogen dioxide and released energy.e.Statements A-D all are correct.

b.Two atoms of nitrogen combine with four atoms of oxygen to produce two molecules of nitrogen dioxide.

Consider the phenomenon of the can being crushed when connected to a vacuum pump that has been turned on. A student draws the following force diagram when trying to describe what is happening after the pump has been running for a short time and the walls of the can are collapsing. a.It is incorrect because both the upward and downward arrows should be the same length. b.It is incorrect because the downward force arrow should be even shorter than it is. c.It is incorrect because the downward force arrow should be longer than the upward force arrow. d.It is correct as is.

d it is correct as it is

Which statement A-D regarding a gas is not correct? a.No interactions occur between molecules other than hard sphere collisions. b.Molecules move in random directions and collide with each other. c.The volume occupied by an individual molecule is negligible. d.All statements are correct

d. All statements are correct

Different liquids have different freezing points mainly because a.Different liquids have different densities b.Freezers are at different temperatures c.The less liquid you use, the faster it freezes d.Molecules of different liquids have a different amount of attraction

d.Molecules of different liquids have a different amount of attraction

John Dalton postulated that all matter is composed of small particles called atoms. For this proposition to be considered a valid scientific theory, ________ a.some, but only a few, experiments may find exceptions to it. b.it must be voted on by the scientific community and accepted by all. c.it must be impossible to prove wrong by experiment. d.all possible experiments must never find an exception to it. e.it must be supported by experimental evidence and testing.

e. it must be supported by experimental evidence and testing.

Which arrow in the following diagrams represents an endothermic (energy transferred in) phase transition?

i and iii (solid, liquid -> gas and solid -> liquid, gas)

Consider the following three small particle theory views of small volumes of materials. Motion is not shown but can be inferred given your past experiences viewing images like this from the simulator movies. Assuming that all three views represent different materials at the same temperature, which view represents a material with the strongest attractive forces between particles?

iii

If the temperature of a gas is increased, its kinetic energy would a.decrease b.increase c.could increase or decrease d.remain the same

increase

Energy that an object has by virtue of its position is called _______

potential energy

Suppose you have a container of air that has a movable top. Assume you then slowly push the top of the container downward, thereby decreasing the volume of the container, but keeping the temperature constant. No gas enters or leaves the system as you push the top downward. What would happen to the average kinetic energy of the particles as you push the top downward? increase decrease remain the same can't be determined without more information

remain the same

What change of state is represented by the following diagram? a.melting b.condensation c.deposition d.freezing e.sublimation

sublimation