Science Semester Test
If a gas occupies a volume of 0.25 L at -2.3 degrees C, by what amount would the volume increase if the gas were heating to 82 degrees C at constant pressure?
0.08 L
A cylinder contains a gas with a volume of 2.7 L and a pressure of 850 Torr at 25 C. What is the temperature if the gas is compressed to 1.9 L at a pressure of 980 Torr, assuming the number of moles of gas remain constant?
-31 degrees C
Which combination best represents the mass and the charge of a proton?
1 amu; positive
5.8 L of gas at 760 mmHg is expanded at constant temperature until pressure is 430 mmHg. What is the final volume?
10 L
At 685 mmHg pressure and 50 degrees C, a gas has a volume of 5.35 L. If the volume of the container decreases to 1.25 L, what is the amount of the pressure charge?
2250 mmHg
If a gas occupies a volume of 0.75 L at 130 kPa pressure, what pressure would the gas exert if it were placed in a 4.0 L container at the same temperature?
24 kPa
A student measures the volume of a liquid in a graduated cylinder of 250 mL capacity, and finds the volume to be 250 mL. the student transfers the liquid to a graduated cylinder whose capacity is
250 mL
One atoms of iron contains 26 protons, 30 neutrons, and 26 electrons. Which of the following would be possible for another atom?
26 protons, 28 neutrons, 26 electrons
Which most likely describes the atomic number of an element?
28
How many electrons are shared when two atoms form a double bond?
4
The three most common isotopes of tin have mass numbers of 118, 119, and 120. If atoms of the isotope with a mass number of 118 contain 68 neutrons, how many protons are contained in the atoms of all isotopes of tin?
50
A student collects a gas in a 250-mL flask. The student transfers the gas to a 500 mL flask, but in the process loses half of the gas. Which will be the volume of the remaining amount of gas?
500 mL
The four natural isotopes of iron have atomic masses of 53.9, 55.9, 56.9, and 57.9. If these were the only isotopes of iron and they occurred in equal abundance, which would be closest to the atomic mass of iron?
56
Isotope A contains 56 protons and 80 neutrons. Isotope B contains 55 protons and 81 neutrons. Isotope C contains 57 protons and 80 neutrons. Isotope D contains 56 protons and 74 neutrons. Which isotopes have the same mass number?
A and B
Isotope A contains 56 protons and 80 neutrons. Isotope B contains 55 protons and 81 neutrons. Isotope C contains 57 protons and 80 neutrons. Isotope D contains 56 protons and 74 neutrons. Which are isotopes of the same element?
A and D
The observation of light during a reaction is usually associated with which of the following?
A chemical change
Which of the following would result in new substances with new properties?
A chemical change
This apparatus produces hydrogen and oxygen gas from water. What occurs during this process?
A chemical change has resulted in different substances, which have different properties than water.
Which of the following can be observed only during a chemical reaction?
A chemical property
A scientific artist is assigned the task of drawing an illustration depicting particles of a liquid. Which of the following best describes the drawing the illustrator should make?
A drawing depicting spheres sliding past one another and fairly closely.
Which of the following best describes a solution?
A homogeneous mixture composed of two or more pure substances in the same state of matter
A student is given a mixture that he is told consists of two pure substances. The mixture is a clear liquid. The student is able to separate the mixture only through distillation. Which were most likely the states of matter of the two substances in the mixture?
A liquid dissolved in another liquid.
The mass of a proton is closest to the mass of which particle?
A neutron
A chemist remotely measures the temperature of a substance as it progresses from a solid to a liquid to a gas. Unfortunately, the chemist is unable to directly observe the behavior of the substance as it is heated. Nevertheless, she is able to describe the period during which the substance melts. What evidence allows the chemist to do this?
A period of constant temperature near the beginning of the experiment
Evaporating water produces gaseous water. What has occurred during this process?
A physical change has not resulted a new substance
Which particle is a neutron most equal to in mass?
A proton
Which of the following is a chemical property?
Ability to react with oxygen in the air
What characteristics do elements within a group share with one another?
All have similar chemical and physical properties
The Statue of Liberty was damaged by corrosion and had to be repaired. Before making repairs, scientists investigated which of the following?
All of the above: The materials used to build the statue, the environment around the statue, the interactions of the building materials with each other and the environment
Chemists have conducted research to learn the best ways to preserve paintings that are 100 or more years old. To do this they must understand the chemical properties of which of these?
All of the above: paint, pigments, and canvas
A chemist analyzes an unknown liquid. The chemist takes samples from the top, middle, and bottom of the samples. Which observation would allow the chemist to reach the conclusion that the liquid could be a pure substance?
All three samples have the same boiling point
A chemist is assigned the task of preparing gold for the manufacture of jewelry. The chemist knows that pure gold is too soft for use in jewelry. She decides to mix the gold with some silver. When she analyzes the metal mixture, she finds that the gold content is the same in all parts of the mixture. Which of the following has the chemist produced?
An alloy of gold and silver
During which physical change does a substance absorb energy from its surroundings?
As it melts, vaporizes, and increases in temperature
Which of the following is not a factor thought to cause periodic trends?
Atomic mass
What describes the number of protons in the atom of a particular element?
Atomic number
Which of the following is not a pattern recognized by the earliest scientists?
Atomic number
What information was added to Dalton's theory as it was refined?
Atoms are composed of subatomic particles
At 25 degrees C, what happens to the pressure of a gas in a sealed container when you compress the gas into a smaller volume?
The pressure increases
Which of the following is the best analogy for describing the arrangement of electrons in an atom according to the Bohr Model?
Balls on steps of a staircase
Which of the following is a physical property?
Boiling Point
A chemist heats a liquid substance. The substance begins to boil and continues to boil for 2 minutes, at which time all of it has been transformed into a gas. The chemist continues to apply heat to the substance. What is happening to the kinetic energy of the molecules of the substance during the stages described above?
Boiling stage: kinetic energy remains constant. Gas stage: kinetic energy increases
What in this image indicates that a chemical change has occurred?
Bubbles rising from the tables
Which pair of atoms is most likely to bond together in a molecule that has resonance structures?
C and O
Which of the following substances would you expect to have a low melting point?
Carbon Dioxide
Coal consists of nearly pure carbon, an element. When coal burns in air, it combines with the element oxygen from the air. Which of the following best describes the product of burning coal?
Carbon dioxide, a compound of atoms of carbon and oxygen
Which of the following is evidence of a chemical change?
Change of chemical composition
In the making of paper, a bleaching agent is added to wood pulp to change one of its properties. The property that is changed is...
Color
What are metalloids used for?
Computer chips
What differentiated Dalton's work from that of the ancient Greeks?
Dalton recognized that each element contains atoms of a unique type
The physical properties of matter produce many cause and effect relationships. Which effect is produced by the close packing of molecules in a solid?
Decreased compressibility
Which of the following observations is always evidence of a chemical change?
Different chemical substances form
What was different about the atomic theory proposed by Niels Bohr?
Electrons energy levels related to their orbits
A student is given an unknown mixture and asked to determine whether it is a solution, suspension, or emulsion. How would the student eliminate a suspension?
Filter the mixture
A solid substance is heated and then cooled. The initial and final temperatures of the substance are the same. How do the initial and final amounts of kinetic energy change?
Final kinetic energy is equal to initial kinetic energy
Which of the following is a physical change?
Freezing
How does thermal energy naturally flow?
From an area of high temperature to an area of low temperature
Which reaction would result in odor, indicating a chemical change has occurred?
Frying and egg
A chemist pieces a sample of matter in a device that applies pressure to the sample. The chemist observes that the sample compresses. Which is the state of the sample?
Gas
Which of the following can be observed without changing the chemical makeup of a substance?
Hardness
Why did Mendeleev organize the elements?
He noticed regular patterns in the properties of elements
A student wants to perform an experiment that will overcome the strong attraction between molecules in a liquid. Which will most likely accomplish this feat?
Increasing the temperature of the system
What does the word atom mean?
Indivisible
The combines gas law is used to solve a problem when...
Initial and final conditions of the gas variables are given.
What are non-metals used for?
Insulators
An engineer discovers that a copper skin of an old yard sculpture is uniformly covered by a layer of blue-green copper sulfate. She chips off some of the copper sulfate and the copper skin into her hand. Which of the following describes the combination of skin and coating of the sculpture she has collected?
It is a heterogeneous mixture
The test tube shown contains a clear liquid and a yellow solid. How can you tell that a chemical change has occurred?
It is impossible to tell because it is unknown whether the solid formed during the reaction
Is the flow of energy during vaporizing more like the flow of energy during melting or during freezing?
It is more like the flow of energy during melting because both processes absorb energy.
A student must write a report that describes three criteria that must be met for a sample of a solid change state to a liquid. Which are these three criteria?
Kinetic energy must be added to the sample. The temperature of the sample must reach its melting point. The molecules in the samples must absorb sufficient energy to overcome the attraction of the molecules in the sample of one another.
A student must prepare a poster display that describes three criteria that must be met for a sample of a liquid to change state to solid. Which are these three criteria?
Kinetic energy must be removed from the sample. The temperature of the sample must reach its freezing point. The molecules in the sample must lose sufficient energy so the attraction of the molecules in the sample for one another exceeds the force that tends to separate them.
Which of the following does not describe a chemical property?
Lead is more dense than gold
During which of the following events would a chemical change occur?
Lighting a firecracker
A student wants to discover the physical property that will spontaneously cause the solid components of a suspension to separate. Which property is it?
Mass
Subatomic particles such as protons and neutrons are similar to fundamental particles because they display which of the following properties?
Mass, Charge, Electromagnetism (all of the above)
A chemist wants to uncover evidence that when molecules of a gas strike the wall of a container, energy is transferred from the molecules to the wall. Which might provide such evidence?
Measuring the temperature of the wall as time passes
Using the combine gas law, what would you expect to happen to the pressure of a gas if the temperature and volume of the gas increase?
The pressure may increase or decrease depending on the magnitude of the temperature and volume change.
Metalloids have properties of what other families or elements?
Metals and non-metals
Which two events must occur for condensation to happen?
Molecules in the gaseous state must lose energy, and the molecules must move closer together.
Which of these elements has the most reactive valence electron configuration?
Na
Where is most of the atom's mass located?
Nucleus
What experimental work led Dalton to his atomic theory?
Partial pressure gas laws
During the process of freezing, which two events are taking place?
Particles are colliding with decreasing force, and they are moving closer together.
What is most likely to cause a fluid to bubble during a reaction?
The production of a gas
How does quantum model of the atom differ from Bohr's model of the atom?
The quantum model describes orbitals as three-dimensional shapes, whereas Bohr's model described electron orbits as flat, circular paths.
A chemist heats four samples of the same substance to the following temperatures: Sample 1 to 30 C; Sample 2 to 15 C; Sample 3 to 45 C; Sample 4 to 35 C; The molecules of which sample will have the greatest motion?
Sample 3
The boiling point of water at sea level under normal atmospheric conditions is 100 C. At what temperature would you predict water will boil on the top floor of a high-rise apartment house?
Slightly less than 100 C
During which changes of state does the potential energy of a system increase?
Solid to liquid, liquid to gas.
When energy is added to an atom, which of the following events is most likely to occur?
Some of the atom's electrons move to a higher energy level
A scientific artist is assigned the task of drawing an illustration depicting particles of a solid. Which of the following best describes the drawing the illustrator should make?
Spheres closely packed in a regular geometric pattern and vibrating in place.
During which of the following process will the chemical composition of a substance remain unchanged?
Sublimation
Which of the following statements is true?
Temperature measures kinetic energy. Which is directly related to gas pressure.
Which two events will increase the rate of evaporation of a liquid?
Temperature will increase, and air pressure will decrease
A chemist discovers that plasmas do not naturally occur on Earth, but do naturally occur on the sun. Which is a reasonable conclusion concerning the conditions required for the production of plasmas?
Temperatures must be very high.
What was the major difference between Dalton's model of the atom and the plum pudding model of the atom?
The addition of electrons to the model of the atom
A student is asked to identify evidence that supports the conclusion that paint is a colloid. Which sets of evidence should the student cite?
The components of paint do not separate spontaneously nor can they be separated by passing the paint through ordinary filter paper.
What did the gold foil experiment demonstrate?
The density of mass in the nucleus
A chemist is given a container filled with a homogeneous liquid. The chemist take samples from different parts of the liquid. which can the chemist expect to find?
The different samples will have the same melting points, boiling points, and densities.
According to Bohr's model of the atom, if one electron in an atom has higher energy than a second electron in the same atom, which of the following must be true?
The higher-energy electron is located farther from the nucleus than the lower-energy electron.
A student heats a solid for 30 seconds. The solid does not melt, but its temperature rises from 20 degrees C to 25 degrees C. What is happening to the kinetic energy of the molecules in the solid?
The kinetic energy is increasing
At atmospheric pressure, what happens if you decrease the temperature of a gas?
The kinetic energy of the gas decreases and the gas takes up less space.
What does the kinetic molecular theory relate?
The kinetic molecule theory relates the properties of a state of matter to the motion of its molecules.
Matter consists of a variety of different sizes with different properties. When comparing protons, molecules, and atoms, which describes a molecule?
The largest of the three particles; has no charge
Which atomic theory did Ernest Rutherford propose?
The nuclear model of the atom
What atomic theory is quantum mechanics associated with?
The orbital model of the atom
Which of the following best describes the difference between a colloid and a suspension?
The particles in a colloid are smaller than the particles in a suspension.
Which process is associated with an increase in kinetic energy, and what experimental evidence supports this?
The period during which a solid is not changing state; its temperature is increasing
A chemist wants to determine which physical factor most influences the motion of molecules in a gas. The chemist proposes four hypotheses to test experimentally. Which hypothesis will most likely be supported by the results of the experiment?
The physical factor that most influences the motion of molecules in a gas is temperature
A student heats a liquid. The liquid begins to boil, and continues to boil for 10 minutes during which its temperature remains constant. During this 10-minute period, what is happening to the potential energy of the liquid?
The potential energy is increasing
What did the cathode ray tube experiment demonstrate?
The presence of electrons in an atom
The graph shows how a substance is affected by changes in temperature. What is happening in Segment 3 of the graph, and how is it affecting kinetic energy?
The substance is liquid that is warming, and its kinetic energy is increasing.
Which statement best describes the interactions of the surroundings with a substance that is freezing?
The surroundings are cooler than the substance and absorb thermal energy from it.
What happens to the surroundings when a substance freezes?
The surroundings get warmer
Charle's law relates ______________...
The temperature-volume relationship of a gas at constant pressure
If the temperature and pressure in a system remain constant, how does increasing the number of moles of a gas affect the gas's volume?
The volume will increase
What is true about atomic orbitals?
They are the most probable location of electrons
What was significant about Aristotle's four proposed elements?
They were believed to be the root of all matter
Which reaction would likely result in a color change indicating a chemical change has occurred?
Toasting bread
Which of the following is least likely to be considered a pollutant?
Water vapor
A student is studying energy changes in a gas. Although she cannot observe the behavior of the individual molecules in gas, she makes four predictions. Which prediction is most likely to be proven correct?
When a molecule of gas strikes the wall of its container, energy will be transferred from the molecule to the wall.
Which of the following elements has the full number of valence electrons in its outermost orbital?
Xe
A student stirs the elements copper and sulfur together and then heats them in a test tube. After heating, the material in the tube does not have the chemical or physical properties of either copper or sulfur. The material in the test tube is most likely...
a compound made of copper and sulfur chemically bonded to each other.
The average kinetic energy of a similar gas molecules is...
directly Proportional to the kelvin temperature of the gas
The properties of a metal, such as conductivity, malleability, and ductility, are the result of ...
freely-moving electrons
From the ideal gas law, the number of molecules of gas is proportional to _____________.
pressure
The frequency of collisions in a gas increase as...
the number of molecules increases per unit volume.
A mineralogist discovers a new substance in a volcanic rock. When the mineralogist searches for more samples of the same substance in rocks from different locations, she should expect the new samples of the substance to have...
the same chemical properties and the same physical properties.
In a hot air balloon, the balloon fills because...
the volume of the air increases as the temperature increases