Module 3 Chem 22 Knewton Alta

Convert from one unit to the other: 2.69 Joules to calories (1.000 cal=4.184 J). 11.3 calories 0.643 calories 1.56 calories 0.372 calories

0.643 calories There are 4.184 joules in 1 calorie. So, divide 2.69 by 4.184 which equals 0.643 calories

Calculate the heat capacity of 18.5 g iron given that 2,982 J is needed to raise the temperature by 194 ∘C. Select the correct answer below: 6.28 J/∘C 12.39 J/∘C 10.27 J/∘C 15.37 J/∘C

15.37 J/∘C

When 5.0 grams of calcium are burned in oxygen, 7.0 grams of calcium oxide result. What mass of oxygen reacted? 1.0 grams 2.0 grams 5.0 grams 7.0 grams

2.0 grams The material gained 2.0 grams of mass which must have come from the oxygen

David is cooking a brisket and needs his casserole dish to be exactly 150∘C. It takes 32,000 J to heat the casserole dish from 0∘C to 150∘C. What is the heat capacity of the dish in joules per degrees Celsius?

213 joules per degrees celcius

Which of the following is TRUE about heterogeneous mixtures? A heterogeneous mixture is a solution. A heterogeneous mixture can only be separated chemically. A heterogeneous mixture is not uniform in composition. A heterogeneous mixture is not a pure substance.

A heterogeneous mixture is not uniform in composition and A heterogeneous mixture is not a pure substance Heterogeneous mixtures are not uniform in composition; this description only applies to homogeneous mixtures. Heterogeneous mixtures, like homogeneous mixtures, are also not pure substances. Since heterogeneous mixtures are not uniform in composition, they are not considered solutions.

Which of the following statements about atoms and molecules are true? Select all that apply: All substances are composed of molecules. Atoms in a molecule are held together by chemical bonds. All molecules are composed of atoms. All substances are held together by chemical bonds.

Atoms in a molecule are held together by chemical bonds and All molecules are composed of atoms. A molecule is defined as two or more atoms joined by strong forces called chemical bonds.

Students in a kindergarten class were each given a ball of sculpting clay with identical masses. Emily used all of her clay to make a ball, and Sarah used all of her clay to make a toy pony. Which of the following statements is true? Select the correct answer below: Emily's ball has less mass than Sarah's pony. Sarah's pony has less mass than Emily's ball. Both clay items have the same mass. It is impossible to determine.

Both clay items have the same mass. The law of conservation of matter tells us that as matter changes forms, mass is conserved. If both of the girls each used all of their clay (which began with identical masses), then each item will have the same mass as in the beginning.

Why are chemists interested in studying thermochemistry? Select all that apply. Heat is often absorbed during reactions. Heat is often released during a chemical reaction, but never absorbed. Heat is often released during chemical reactions. Heat is often absorbed in a chemical reaction, but never released.

Heat is often absorbed during reactions and Heat is often released during chemical reactions Heat is often absorbed and released during chemical reactions as a way of energy changing forms. Therefore, chemists study thermochemistry as a way to understand what is happening during certain chemical reactions.

A chef places a cold glass of water into a hot pan. Which of the following is true about the heat flow between these two bodies? Heat will flow from the water to the pan, making the pan colder. Heat will flow between the water and the pan until the pan is colder than the water. Heat will flow around the water and the pan, keeping the pan warmer than the water. Heat will flow from the pan to the water, making the water warmer and the pan colder until they are both the same temperature.

Heat will flow from the pan to the water, making the water warmer and the pan colder until they are both the same temperature. Heat is the transfer of thermal energy between two bodies at different temperatures. Heat flows from substances with high temperatures to substances with low temperatures, thus making the warmer object cooler and the cooler object warmer. Remember that heat NEVER flows from the cooler object to the warmer object. The warmer object becomes cooler because it is losing heat energy to the cooler object.

How is it possible that energy is always conserved, but we are always saying we need to "conserve more energy"? Select the correct answer below: The total amount of energy in any process varies. The total amount of energy in any process decreases. The total amount of energy in any process is fixed. The total amount of energy in any process increases

The total amount of energy in any process is fixed. When we say energy is always conserved we mean the total amount of energy in any process or reaction never changes - it is fixed. When we tell ourselves to conserve energy we mean to use less of it by doing things like driving more fuel efficient cars, or insulating our houses better.

An energy conversion is best defined as The loss of energy during any given activity. The total quantity of matter and energy in the universe. The transformation of energy from one form to another. The amount of energy that is released during a physical or chemical change

The transformation of energy from one form to another An energy conversion, also known as an energy transformation is when one form of energy changes to another form. Energy is never created nor destroyed it simply changes forms. Examples of energy conversion/transformation are when potential energy changes to kinetic energy as water falls over a cliff, or light energy changes to electrical energy in a solar panel.

Which of the following is true about thermochemistry? Thermochemistry involves studying the release and absorption of heat energy. Thermochemistry only involves the study of solar energy. Both chemical and physical changes are studied in thermochemistry. Understanding the principles of thermochemistry is important for a wide variety of disciplines.

Thermochemistry involves studying the release and absorption of heat energy, Both chemical and physical changes are studied in thermochemistry, Understanding the principles of thermochemistry is important for a wide variety of disciplines. Thermochemistry involves studying the release and absorption of heat energy during chemical and physical changes, and it is used in a great many disciplines.

Which of the following statements is true regarding weight and mass? Mass is the amount of force that gravity exerts on an object. Weight is the amount of matter an object has. Mass of an object is not constant. Weight is dependent on a source of gravity.

Weight is dependent on a source of gravity. Gravity is the force that gives objects weight. While mass remains constant, regardless of where the object is, weight can change based on the gravitational force placed on that object.

A child on a sled starts at the top of a hill with 90 J of potential energy. At the bottom of the hill, she has only 55 J of kinetic energy. Assuming that at the top of the hill she has only potential energy and at the bottom she has only kinetic energy, what can we conclude? (Remember, potential energy is the energy of position while kinetic energy is the energy of motion.) Select the correct answer below: Work must have been done. The child is not good at sledding. At some point, the child hesitated going down the hill. The child sleds down one hill but is about to go up another hill

Work must have been done. There was a change in the amount of energy so work must have been done. Motion is definitely indicated which shows work has been accomplished. The other 3 choices are assumptions which cannot be empirically obtained in this problem.

What is the amount of energy required to raise one gram of water by 1∘ C? a joule a calorie a kelvin a heat index

a calorie A calorie is defined as the amount of energy required to raise the temperature of one gram of water by 1∘ C

Which of the following is NOT a substance made of one type of molecule. carbon dioxide glucose water a cell within the human body

a cell within the human body A cell is a collection of many different types of molecules.

A molecule that is made up of more than one type of atom is known as an element an isotope a compound a subatomic particle

a compound

Which of the following terms describes the smallest particle of a substance that still retains the chemical properties of that substance? Select all that apply. a mixture a molecule an atom a neutron

a molecule and an atom Depending on whether the substance in question is an element or a compound, either an atom or a molecule is the smallest particle of that substance that retains its chemical properties. A substance cannot decompose into protons, neutrons and electrons without changing its very nature.

If something is a compound, it is also __________ . an element a pure substance a mixture a single atom

a pure substance Pure substances are either elements or compounds. A compound is a pure substance composed of more than one element. A compound is not a mixture because mixtures can be separated by physical means. Since a compound is composed of more than one type of atom, it cannot be a single atom.

Which is an example of a homogeneous mixture? air breakfast cereal soil oxygen

air Air is an example of a homogeneous mixture, oxygen is an element and the remaining options are heterogenous mixtures.

Which of the following states of matter can exert pressure? solid liquid gas all of the above

all of the above All the phases of matter can exert pressure.

Which object has the most gravitational potential energy? an airplane in mid-flight a baseball held by a pitcher a bird on top of a flagpole these objects all have the same gravitational potential energy

an airplane in mid-flight An object's gravitational potential energy increases with increasing height and with increasing mass. Thus the plane, having both the highest altitude and greatest mass, will have the greatest potential energy.

A mixture can be made up of two or more: elements compounds pure substances any of the above

any of the above A mixture is made up of a combination of two or more pure substances, which could be elements, compounds, or both. A compound is also made up of two or more elements, but only in a specific ratio, while a mixture of two or more elements is not.

What can be observed without changing the composition of matter? flammability reactivity boiling point toxicity

boiling point A physical property can be observed without changing the composition of matter. Flammability, toxicity, and reactivity are all chemical properties, whereas boiling point is a physical property.

Heat capacity depends on __________. the composition of the substance the amount of the substance both A and B neither A nor B

both A and B Heat capacity is an extensive property in that it depends on the composition and amount of a substance. For example, a metal wire tends to have a lower heat capacity than most amounts of water; a wire heats up and cools down much faster than water (i.e., it depends on the substance's composition). Also, a small amount of water has a lower heat capacity than a large amount of water. The ocean has a relatively stable amount of heat, while heat changes dramatically in a puddle (i.e., it depends on the amount of substance). This is different from the specific heat capacity, which is an intensive property and is independent on the amount of substance and depends only on the composition of the substance.

An example of a homogeneous mixture is: gold brass aluminium copper

brass A homogeneous mixture is a substance with uniform composition throughout. Brass is a mixture of copper and zinc. All other options are pure substances (elements).

Which of the following is considered a chemical change? crumpling a piece of paper into a ball burning wood in a fireplace digesting a delicious sandwich crushing ice for a soda

burning wood in a fireplace and digesting a delicious sandwich The processes of burning wood and digesting food are chemical changes. When wood is burned, the wood reacts with the oxygen in the air, causing new substances: ash and smoke, to be created. When food is digested, it is broken down into smaller chemical components by the use of digestive enzymes. Since these examples both result in changes to the chemical composition of the original substances, they are considered chemical changes. Crumpling paper and crushing ice, however, are physical changes. The actions of crumpling and crushing do not change the chemical composition of the original substances (they are still paper and ice, respectively).

Sugar and water, with appropriate heat, can create caramel. In this example, sugar is undergoing a ___________. electrical change kinetic change chemical change physical change

chemical change Sugar and water, when forming caramel, are undergoing a chemical change.

The kind of energy stored within the bonds of molecules is called: kinetic energy mechanical energy electromagnetic energy chemical potential energy

chemical potential energy The energy stored within covalent chemical bonds is called chemical potential energy, which is what is used to power our bodies in their day-to-day motion.

A molecule comprised of more than one type of atom is called a(n): compound mixture element reactant

compound A mixture is composed of two or more types of matter and can be separated by physical changes. Elements are pure substances that cannot be broken down into simpler substances by chemical changes. And reactants are substances undergoing reaction.

When an object's temperature __________, it will most likely contract. increases remains constant decreases none of the above

decreases When an object's temperature decreases, it will most likely contract. Most (but not all) substances behave this way.

A homogenous mixture varies from a heterogenous mixture in that a homogenous mixture has properties that: do not vary in the mixture vary in the mixture suspend in a liquid dissolve a solute

do not vary in the mixture A homogenous mixture varies from a heterogenous mixture in that a homogenous mixture has a uniform composition.

When a substance undergoes a chemical reaction, which of the following will NOT change? Select all that apply: temperature energy density mass

energy and mass Due to the Law of Conservation of Energy (energy can be neither created or destroyed) and the Law of Conservation of Mass (there is no detectable change in the total amount of matter during a chemical change), neither energy nor mass has detectable change when undergoing a chemical reaction. The total quantity of matter and energy in the universe is fixed.

Which of the following are types of energy? Select all that apply: metabolism heat chemical potential kinetic thermochemistry

heat chemical potential kinetic Heat, chemical, potential and kinetic are all types of energy. Potential energy is the energy an object has by virtue of its position in a field and it converts to kinetic energy which is the energy of motion. Thermochemistry is the study of heat exchange during chemical reactions and metabolism is the process of converting chemical energy to usable energy in a living organism.

What is the SI unit of heat, work, and energy? joules calories Kelvin Celsius

joules Joules are the SI unit of heat, work, and energy.

Heat energy is measured in units of __________. (Select all that apply) degrees Celsius joules calories degrees Kelvin

joules and calories The units we use for measurements of heat energy are calories or joules. Degrees Celsius and degrees Kelvin are units of temperature, not heat energy.

Which physical form of matter has a definite volume, but no definite shape? gas solid liquid solid and gas

liquid Liquid is a physical form of matter that has a definite volume, but no definite shape. A solid has a definite volume and definite shape, and a gas has no definite volume or shape.

An object that is classified as having a low temperature will have __________ thermal energy. high low no There is not enough information to answer this question.

low An object that has a low temperature will have low thermal energy.

Which of the following is an example of a homogenous mixture? oil and vinegar salad dressing chocolate chip cookie soil maple syrup

maple syrup Maple syrup is an example of a homogenous mixture. Salad dressing, chocolate chip cookies, and soil are all examples of heterogeneous mixtures.

Which of the following is measured in grams or kilograms? mass weight density volume

mass Mass is measured using grams or kilograms.

A __________ contains more than one type of substance as part of its composition. mixture pure substance compound element

mixture A mixture contains more than one type of element or compound. A mixture can be categorized as homogeneous or heterogeneous depending on whether it has a uniform composition or not.

Compared to a gas, the molecules of a liquid: move more rapidly, and are farther apart move more rapidly, and are closely together move more slowly, and are packed closer together move more slowly, and are farther apart

move more slowly, and are packed closer together Molecules of a liquid do not move as rapidly, and are not as spread out as molecules of a gas. They have less kinetic energy than gas molecules.

An atom of an element can be split into smaller components by what kind of process? a physical process a chemical process magnetic force none of the above

none of the above An atom of an element cannot be split into its components by either a physical or chemical change. Splitting an atom is a nuclear process.

Which of the following events fail to follow the law of conservation of matter? Burning wood for a fire Freezing water into ice cubes The decomposition of MgCl2 into Mg and Cl2 None of these

none of these All of these events follow the law of conservation of matter.

The energy an object has by virtue of its position in a field is called: mechanical energy kinetic energy potential energy chemical energy

potential energy Whether a gravitational field or an electromagnetic field, the energy an object has because of its position with respect to an attracting object is called potential energy.

______________ determine what element an atom belongs to, while ______________ allow atoms to do chemistry. electron, neutrons protons, electrons neutrons, protons electrons, protons

protons, electrons The number of protons determines an element's atomic number, while electrons participate in bonding to form molecules.

How does a mixture differ from a pure substance? pure substances are easily separated into components, mixtures are not mixtures all have uniform compositions, pure substances do not pure substances have constant chemical and physical properties while mixtures are varied mixtures require chemical methods of separation while pure substances can be separated by physical means

pure substances have constant chemical and physical properties while mixtures are varied Mixtures can be classified as homogenous or heterogenous and can be separated into their component parts by chemical or physical means. Pure substances have constant chemical and physical properties while mixtures can be varied.

Which of the following is an example of a heterogenous mixture? gasoline air a sports drink salad dressing

salad dressing Salad dressing is an example of a heterogenous mixture as it has a varied composition throughout. The remaining choices are homogeneous mixtures as taking any sample of them would result in a uniform composition from each sample.

An example of homogeneous mixture is: muddy water pure water ice water saline water

saline water A homogeneous mixture has uniform composition for any given sample. A saline water solution has equal parts of salt dissolved throughout. Muddy water and ice water are heterogenous mixtures while pure water is a compound (and a pure substance).

What physical state of matter is associated the particles having least amount of thermal energy? gas solid liquid All phases of matter contain the same measure of thermal energy.

solid Solids have the most rigidly packed particles (molecules, ions, or atoms) because they have the lowest amount of thermal energy compared to the other states of matter for that substance.

Which of the following can be characterized as a physical change? an iron pipe rusts milk goes sour firewood burns sweat evaporates from your skin

sweat evaporates from your skin Sweating is an example of a phase transition (from liquid to gas) which is a physical change. An iron pipe rusting, milk turning sour, and firewood burning are examples of chemical changes.

What determines the mass of an object? the volume of the object the weight of the object the density of the object the amount of matter in the object

the amount of matter in the object The amount of matter in the object determines the object's mass.

What is the definition of energy? the absolute motion an object possesses the capacity to supply heat or do work the flow of temperature in an object the ability to carry out all processes

the capacity to supply heat or do work Energy is defined as the capacity to supply heat or do work. The two main types of energy are potential energy and kinetic energy.

Which of the following is NOT a likely indicator of a chemical change? the formation of a precipitate a color change the change in shape of a malleable metal the release of gas without adding heat or lowering the pressure

the change in shape of a malleable metal The bending of a piece of metal, like a paper clip, is not a chemical change. Only when a new substance is formed, evidenced by a new material present or a change in color, can a chemical change be guaranteed.

In order to identify a chemical property of matter, one thing scientists might look for is: a change in shape of the substance. a change in state of matter. the formation of a precipitate. the freezing of a substance

the formation of a precipitate. In order to identify a chemical property for a type matter, scientists look for a chemical change, such as the formation of a precipitate during a reaction.

Which of the following objects has more kinetic energy than it does potential energy? a compressed spring in a pinball machine just before the ball is launched a rollercoaster motionless at the top of a track a yo-yo before it is released the pendulum of a grandfather clock at the lowest point of its arc of motion

the pendulum of a grandfather clock at the lowest point of its arc of motion Kinetic energy is the energy of motion. Each of the objects above are motionless—with stored potential energy—except for the clock. At the bottom of its arc it will have the greatest kinetic energy, which is then converted to potential energy as it swings back up to one side.

If you boil a sample of water, the steam that results will have: less mass than the water more mass than the water the same mass as the water impossible to predict

the same mass as the water The law of conservation of matter tells us that mass is conserved as matter changes forms. Therefore, all the water molecules in the steam will have the same mass as when they were in the liquid form.

All of the following are physical properties EXCEPT: texture density toxicity boiling point

toxicity All of the above are physical properties EXCEPT toxicity. Physical properties are characteristics of matter that can be seen about a substance without changing that substance's chemical composition.

Which of the following is measured using Newtons (a unit of force)? mass weight density volume

weight Weight is measured using newtons, a unit of force.