UNIT 2
MATTER – PROPERTIES AND CHANGES
MATTER(pp 21 – 24)
1. Matter is anything that has mass and volume.
2. The amount of matter in an object is known as ______.
3. The amount of space an object occupies is known as ______.
Basic Units of Matter
1. ______are the basic units of matter.
2. There are over 110 different kinds in the known universe. These are catalogued on the periodic table.
3. Atoms combine to form ______. Molecules are a neutral group of atoms held together by chemical bonds.
4. A molecule may contain any number of atoms, but it behaves as one unit.
PROPERTIES OF MATTER(pp. 29 - 34)
1. Different types of matter are described by listing their characteristics, or properties.
2. Some properties of matter used to describe things are:
3. Properties fall into two basic categories: ______and ______.
Physical Properties
1. These are properties that can be observed or measured without changing the composition of matter.
2. Examples are:
3. The ______of matter is also a physical property.
4. The three common states of matter are:
5. Solids have a fixed volume and shape. The atoms and molecules are held tightly in a rigid structure, but do vibrate slightly about fixed positions.
6. Liquids have a fixed volume, but a variable shape. The atoms and molecules are not held together in a rigid manner. This allows them to move past one another and flow.
7. Gases have no fixed shape or volume and therefore expand to fill any container they occupy.
8. The word ______refers to the gaseous state of a substance that is a solid or a liquid at room temperature.
9. A fourth state, ______, exists at very high temperatures.
10. In this high-energy state the atoms are torn apart into smaller pieces called ______.
11. A fifth state of matter, called the ______, was proposed in 1925 by a physicist from India, Syendra Bose, and confirmed by Albert Einstein. It exists as temperatures nearing absolute zero.
Intensive and Extensive Properties
1. A way to further describe physical properties.
2. An ______property is a physical property that depends on the quantity of matter present.
3. ______properties are physical properties that depend on how matter is structured.
Chemical Properties
1. These are properties that can be observed only when substances interact with one another.
2. Examples are:
***** Classify the following as a chemical property, intensive physical property, or extensive physical property:
blue colorreacts with an acid
densitysour taste
flammabilitymelting point
solubilitycombustibility
hardnessreacts with water
odorluster
boiling pointliquid
CONSERVATION OF MASS
1. Although matter can undergo both physical and chemical changes, the total amount of matter does not change.
2. This is obvious for physical changes, but not always so for chemical changes.
3. Early scientists used analytical balances to determine the mass of the reactants and products. They discovered both were equal.
4. The ______state that mass is neither created nor destroyed during a chemical reaction – it is conserved.
5. In the form of an equation, it looks like:
6. Lavoisier discovered that when mercury(II) oxide decomposes to form mercury and oxygen, the mass of the reactants will equal the mass of the products.
***** A 10.0g sample of magnesium reacts with oxygen to form 16.6g magnesium oxide. How many grams of oxygen reacted?
MATTER CHANGES (pp. 29 - 34)
1. A ______is one that affects physical properties only. The basic identity and structure of the material does not change.
2. Changes of state are physical changes.
3. Some changes involve the rearrangement of atoms and the production of new materials.
4. These are called ______.
5. During a chemical change atoms are rearranged, but there is no loss or gain in the total number of atoms.
6. In the process of both physical and chemical changes, energy can be either released or absorbed. These changes, where energy is transferred from the system to, or from, the surroundings, have been given special names.
7. An ______is a physical/chemical change during which the system absorbs energy from its surroundings.
8. An ______is a physical/chemical change during which the system releases energy to its surroundings.
***** Classify each of the following as either a physical or chemical change. If applicable, also indicate whether the change is endothermic or exothermic:
grinding coffee beansslicing bread
digesting toastmelting ice cream
toasting a marshmallowJell-O solidifying
CLASSIFICATION OF MATTER (pp. 24 – 29; 34 - 39)
Mixtures and Pure Substances
1. A ______is matter made up of only one kind of atom or molecule.
2. Pure substances have a fixed composition and a unique set of properties.
3. Both elements and compounds can be pure substances.
4. A ______is a collection of two or more pure substances that are physically mixed together. Thus, a mixture cannot be represented by a chemical formula.
5. The properties of different substances in a mixture can vary.
6. The properties of mixtures can vary. Each substance in a mixture retains its chemical identity.
Classification of Mixtures
1. Mixtures can be further classified as either ______or ______.
2. A homogeneous mixture is one in which the substances are uniformly distributed throughout.
3. A heterogeneous mixture contains substances that are not evenly distributed.
4. Some parts of a heterogeneous mixture have different properties than other parts.
5. Homogeneous mixtures are also known as ______.
6. Solutions can be gaseous, liquid, or solid.
Elements
1. ______are the simplest pure substances because they contain only one type of atom. An element cannot be separated into simpler substances by physical or chemical means.
2. Every element has its own unique set of physical and chemical properties.
3. There are 91 naturally occurring elements 118 known elements.
4. About one dozen elements compose the things we notice every day.
5. Elements can consist of single atoms or be diatomic.
6. Some elements have ______.
7. Allotropes are different molecular forms of an elements that exist in the same physical state.
Compounds
1. ______are pure substances that are composed of two or more different elements that are chemically combined.
2. They are created when atoms of different elements join together in a chemical reaction.
3. Every compound has a unique set of properties. These properties are often very different from the properties of the elements that make up the compound.
***** Classify each of the following as an element, a compound, a homogeneous mixture, or a heterogeneous mixture:
airbronzemercury (Hg)copper (II) sulfate
(CuSO4)
wineglucose (C6H12O6)iron ore
table salt (NaCl)mayonnaiseoil & vinegar dressing
Family Tree
1. In summary the family tree for matter looks like:
SEPARATION TECHNIQUES (pp. 39 - 41)
1. In order to study the composition of mixtures, they must be separated. This can be accomplished using a variety of physical means.
2. These separation techniques make use of differences in the physical properties of the materials in the mixture.
3. Thus, the materials obtained are not chemically changed by the process.
Techniques
1. ______is used to separate heterogeneous mixtures of solids and liquids by using a porous barrier. The liquid passes through leaving the solid behind.
2. ______is used to separate solids and liquids by allowing the liquid to evaporate, leaving the solid behind.
3. ______uses spinning forces to pull all suspended solids to the bottom of the tube leaving a liquid layer on top.
4. ______is pouring the liquid layer off the top of a solid-liquid mixture once the solid has settled or been centrifuged to the bottom. This can be done with liquid layers, but it is more difficult.
5. ______separates the components of a solution. The components (mobile phase) travel across the surface of another material (stationary phase)at different rates based on each other’s attraction to the stationary phase.
6. ______separates the components of a solution based on differences in the boiling points of the substances involved.
***** Ocean water can be made suitable for drinking by boiling the water and then condensing the vapor back to the liquid state. What is the name of this process?
***** A forgetful student leaves an uncapped watercolor marker on an open notebook. Upon returning she discovers the leaking marker has produced a rainbow of colors on the top page.
a. Is the ink a pure substance or a mixture?
b. How do you know?
c. What separation technique is involved.
STANDARD UNITS
1. In 1960, scientists adopted a part of the metric system to use as the standard scientific system of measurement units. This is called the “Systeme Internationale” or SI.
2. There are seven basic units. These base units can be combined in various ways to describe nearly all physical measurements. They are:
QuantityUnitSymbol
Length
Mass
Time
Electric current
Thermodynamic
temperature
Amount of
substance
Luminous intensity
PREFIXES
1. Any SI unit can be modified with prefixes to match the scale of the object being measured. Meters might be suitable for measuring a person’s height, but not the diameter of a living cell.
2. The prefixes can be combined with various units to describe the size of a measurement.
***** Suggest appropriate SI units and prefixes to measuring the following objects:
- the length of your chemistry book
- the volume of a bathtub
- the mass of an eyelash
- the volume of an aluminum soda can
DERIVED UNITS - VOLUME
1. The seven base SI units cannot measure every observable property; therefore derived units are created by multiplying or dividing the seven base units in various ways.
2. The derived unit for volume is obtained by using length, width and height measured in meters:
3. We are more familiar with using the liter, L, as a volume unit.
4. More commonly we use the following units to measure volume:
***** Speed is calculated from length and time according to the following equation. What is the derived SI unit?
Speed = distance / time
DENSITY (pp 142 - 146)
1. Density is an intensive property. It does not depend on the quantity of matter present.
2. Density represents a ratio of mass to volume.
3. One interpretation of density is that it is a measure of how tightly matter is packed together.
4. Because the density of a substance is the same for all size samples of that substance, density can be used as a means of identifying materials.
5. To calculate density, one uses the following equation
6. The units for density are usually:
***** Determine the density of a piece of iron whose mass is 31.2 g and volume is 4.00 mL.
***** Clover honey has a density of 0.498 g/mL. Determine the mass of a sample having a volume of 225 mL.
***** Determine the volume of a piece of copper whose mass is 10.5g. The density of copper is 8.94 g/mL.
***** To determine the density of ethyl alcohol, a student pipets a 5.00 mL sample into an empty flask whose mass is 15.246g. She finds that the mass of the flask and the ethyl alcohol is now 19.171g. Calculate the density of the ethyl alcohol.
***** A solid with an irregular shape and a mass of 12.65g is added to a graduated cylinder filled with water to the 29.7 mL mark. After the solid sinks to the bottom, the water level of the graduated cylinder is read to be 36.6 mL. Calculate the density of the solid.