Chapter 2

Question 1

What are the general properties of matter?

Answer 1

1.Matter is anything that takes up space and has mass. Some general properties would be mass, density, physical, and chemical properties.

Question 2

Define density and explain how it is determined

Answer 2

1.Density is how much matter is contained in a certain volume.

Question 3

A boat made out of dense material can float how?

Answer 3

If it has an air pocket, and A boat made out of dense material will float if the material’s density is less then 1. You find it by m/v

Question 4

What is the difference between heterogeneous and homogeneous matter?

Answer 4

1.Heterogeneous Matter has different chemical properties throughout. Homogeneous Matter has the same chemical properties in every sample you take.

Question 5

What is a pure substance

Answer 5

1.A pure substance is a compound that has a fixed chemical composition.

Question 6

What is an element?

Answer 6

1.An element is the simplest pure substance because it is made up of only one kind of atom. This atom is the simplest kind of matter and the element is made only with the required amount of this atom.

Question 7

What are atoms?

Answer 7

An atom is the simplest kind of matter. It maintains the properties of the element that it makes it.

Question 8

What are the rules about writing elements?

Answer 8

1.You would use either a capital letter or a capital letter and a lower case letter. The lower case letter could be determined by the 2nd or 3rd letter.

Question 9

What are compounds and what are molecules

Answer 9

A compound is formed when two or more elements are chemically combined. The molecule is the smallest unit of the compound that will keep all the chemical and physical properties.

Question 10

What is the meaning of subscripts and coefficients in chemical formulas? What are the correct ways to write them?

Answer 10

1.Subscripts in a chemically formula usually tell how many atoms of the element are there. When you write. Coefficients are used when telling how many molecules of a compound are there. For that, you could use the rules of subscripts which are just like those of exponents.

Question 11

What is a mixture

Answer 11

1.A mixture is when two substances are combined but not chemically. Each individual substances retains its physical properties. You could always separate the mixture back into its original contents

Question 12

What is a solution, a colloid, and a suspension?

Answer 12

1.A solution is a mixture of two or more substances. The particles in a solution are atoms and molecules which are to small to be seen. They are the smallest in the whole thing. A suspension is a mixture where the particles are more or less evenly dispersed throughout a liquid or gas. Suspensions always have particles that are large enough to interfere with light.. This is a heterogeneous mixture. A colloid is a mixture that has tiny particles that are intermediate in size, between those in solutions and this in suspensions. They are suspended particles. They are medium sized particles that can be distinguished and interfere with light. They let light pass through while suspensions do not. A solution also lets light pass through.

Question 13

What are some examples of mixtures?

Answer 13

1.A mixture could be Gatorade, carbon dioxide, or a rock/mineral.

Question 14

Define solvent, solute, solubility, and alloy

Answer 14

1.A solution is a mixture where something is dissolved in another. The smaller amount or that which is being dissolved is called the solute. The larger amount, or that which is taking in is called the solvent. How well a substance dissolves can be classified as solubility. You can say that a substance is insoluble, if it does not dissolve. You can also say that it is slightly soluble if you need to add more solvent for it to dissolve. An alloy is a mixture of metals. They are very popular with jewelry. Basically, you heat many metals to a very high temperature, and then you mix them, so that their molecules fit in between each other. Then, you harden it by cooling it.

Question 15

How would scientists classify rocks and minerals?

Answer 15

1.Scientists would classify rocks as mixtures because they are a mixture of different elements or compounds.. Minerals, are always compounds or elements-pure substances.

Question 16

How do the properties of compounds compare to the properties of their component elements

Answer 16

1.Properties of compounds are unique properties—they are different from the properties that their components have. Components elements would have the properties of their elements.

Question 17

What is the difference between chemical and physical properties?

Answer 17

1.Chemical properties require the presence of another substance to be there. Physical properties are those that can change without actually changing the identity of the substance. Also, they DON’T require the presence of another substance…they are also easily observed.

Question 18

What is the difference between chemical and physical changes

Answer 18

1.Physical changes are those that don’t actually change the identity of the substance. They would just change the size, density, color, odor—without changing the chemical composition. Chemical changes actually changes the substance so that it results in a different substance ( like a compound– a different make up of atoms)

Question 19

Describe how to detect whether a chemical change has occured

Answer 19

1.You could detect that a chemical change has occurred when the reactivity, flammability, or odor has changed.

Question 20

Describe how you can seperate parts of a mixture, are these chemical or physical processes?

Answer 20

1.You could separate a mixture physically, by using liquids that they are soluble in. This would help, because if the mixture has one substance that is insoluble, you could dissolve it in the liquid and then separate the other substance from the liquid using a filter. Really, you could find a physical property in the substances that is NOT the same and use that to your advantage (size, magnetism, boiling point—convert into different phases so that one changes before the other)These are physical changes because you are not really changing the chemical composition of the substances.

Question 21

What are the 4 states of matter?

Answer 21

1.The four states of matter are:solid, liquid, gas, and plasma. The molecules of a solid are packed together and are not compressible. In a gas, the particles are spread apart (very wide) and they are moving at a very fast rate. Gas has low density, but will fill whatever container it is in. Gas cannot be determined with shape, because it takes up whatever shape. It has a changing volume- depending on the container. The liquid however has particles that move at very middle rates, The liquids particles have a smaller distance between them, but the molecules move past each other. The liquids will fit the shape of whatever container they take. They have a fixed volume but take the shape of their container. In addition to that, solids are much like liquids. The particles are fairly close together, but they only vibrate: they don’t move. Solids will have a volume, and you can find that depending on the shape that they take up. They will have a fixed shape and volume. Lastly, plasma is very gaseous, except the particles could be ionized (when they loose or gain an electron). Heating a gas can ionize it, (reducing electrons). In plasma, the electrons have dis-attached themselves from the nucleus. Only when there is a major temperature drop, will they morph back together.

Question 22

Describe phase changes

Answer 22

1.Phase changes that occur in matter are melting, boiling, vaporization. Boiling is when, you heat a liquid to the temperature that it boils at and then turn it into vapor. Freezing, is when you cool a liquid enough to take away some heat energy, and compact the molecules so that it becomes a solid. Melting is when you add heat energy to the solid, so much so that the distance between particles expand and it becomes a liquid. Condensation is when a gas is changed into a liquid (the opposite of vaporization). Sublimation is when a solid goes directly into a gas. This can happen if the pressure is enough. Depositing is when a gas changes directly into a solid.

Question 23

Interpret a phase change diagram. How are they related to changes in heat energy and temperature (is heat added or taken away)

Answer 23

1. Part of the phase change diagram is that, at the beginning it will at a certain temperature. Because one of the phase changes is transitioning it from a solid into a liquid, one will have to use the CSP to determine the rise in temperature , and how much the capacity is. Then, you will start melting the solid once you get it to 0 degrees. This will keep the line constant, because no temperature change is needed for the solid to start melting IF it is at 0 or slightly above. Note that the solid will remain frozen even if it is 0.000001 degrees below zero. Also, all of the energy is used towards spreading the molecules apart. You use the HF to determine how many Joules this process takes Next, after you have melted the solid into a liquid, you have to raise the temperature to bring it up to 100 degrees so that it will start to boil and vaporize. This means that you use the CSP. Once you get to 100 degrees, you must us HV to determine how much energy is being put into the process of making it a gas. So, you use the HV, and keep it a horizontal line. Then, you use the CSP, because once the motion is in place, the temperature will rise once again. Temperature is the degree of pressure on an object. It is the measure of average kinetic energy. Heat energy is a form of heat that is transferred when there is a difference in temperature. Heat energy is the potential energy. It has the potential to do work,

Question 24

Define specific heat capacity, heat of fusion, and heat of vaporization

Answer 24

1.Specific Heat Capacity is the amount of energy (J) that it takes to raise the measure by 1 unit. This is measured in terms of J/g*C. Heat of Fusion is the amount of energy/heat required to change the solid into a liquid without changing temperature. This is measured in J/g. For water it is 334. Heat of Vaporization is the amount of heat/energy that is required to convert a liquid into vapor without changing the temperature (2260).

Question 25

What are some other informations?

Answer 25

Definitions: A solution is: a homogeneous mixture in which two are more substances are mixed together and distributed evenly.
Mixture: can be homogeneous or heterogeneous. Not chemically combined.

The term ‘change of phase’ means the same thing as the term ‘change of state’.
There are four states, or phases, of matter. They are:
Solid
Liquid
Gas
Plasma
We will not be discussing the plasma state here.
When a substance changes from one state, or phase, of matter to another we say that it has undergone a change of state, or we say that it has undergone a change of phase.
These changes of phase always occur with a change of heat. Heat, which is energy, either comes into the material during a change of phase or heat comes out of the material during this change. However, although the heat content of the material changes, the temperature does not.
Here are the five changes of phase. They are diagrammed in the above animation and listed below.
Description of Phase Change
Term for Phase Change
Heat Movement During Phase Change
Temperature Change During Phase Change
Solid to liquid
Melting
Heat goes into the solid as it melts.
None
Liquid to solid
Freezing
Heat leaves the liquid as it freezes.
None
Liquid to gas
Vaporization, which includes boiling and evaporation
Heat goes into the liquid as it vaporizes.
None
Gas to liquid
Condensation
Heat leaves the gas as it condenses.
None
Solid to gas
Sublimation
Heat goes into the solid as it sublimates.
None
So, how could there be a change in heat during a state change without a change in temperature? During a change in state the heat energy is used to change the bonding between the molecules. In the case of melting, added energy is used to break the bonds between the molecules. In the case of freezing, energy is subtracted as the molecules bond to one another. These energy exchanges are not changes in kinetic energy. They are changes in bonding energy between the molecules.
If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance. The example we will use here is ice melting into water. Immediately after the molecular bonds in the ice are broken the molecules are moving at the same average speed as before, so their average kinetic energy remains the same, and, thus, their Kelvin temperature remains the same.
Look at the following diagram and continue to read the text below it. The molecule of ice and the molecule of water (the black balls) are moving with the same rate of vibration in this diagram. This is meant to show that they have the same average speed and thus the same average kinetic energy (since they have the same mass) and thus the same Kelvin temperature. The motions are, though, greatly exagerated. Actually, the motions of the molecules should be considered tiny vibrations.
In the ice the molecules are strongly bonded to one another, thus forming a rigid solid. When heat is added to the ice it melts, and these bonds are broken, The molecules afterward bond to one another with less strength, and water is formed.
Now, before the melting, the molecules were actually moving when in the solid state. They were vibrating back and forth. They had an average kinetic energy. So they had a Kelvin temperature proportional to this average kinetic energy.
After the melting the water molecules are moving, also. And they have the same average kinetic energy as they had before the melting. So, the water is at the same temperature the moment after the melting that the ice was at the moment before the melting.
Heat came into the situation, but it was not used to change the kinetic energy of the molecules. It was used to change the bonding between the molecules. Breaking the bonds between the molecules of the ice requires energy, and this energy is the added heat.
In a similar way heat enters a liquid to change the molecular bonding when the liquid boils or evaporates into a gas, and heat enters a solid to change the molecular bonding when it sublimates into a gas.
In an inverse way heat leaves a gas to change the molecular bonding when the gas condenses into a liquid, and heat leaves a liquid to change the molecular bonding when it freezes into a solid.
In none of these changes of state is the heat (energy) that is input or output used to change the speed of the molecules. The average speed of the molecules is the same before and after a phase change, and so is the average kinetic energy. And so, again, note that the temperature does not change during a change in phase, since it is proportional, in Kelvin degrees, to the average kinetic energy, which does not change.