Physical Properties &Changes in Matter

Question 1

Matter

Answer 1

Can exist in different states. Physical properties of matter are Mass, Density, and Volume.

Question 2

Physical Properties of Matter: Mass, Volume, and Density I

Answer 2

Physical Properties refer to observed properties of the substance and those that can change the state without changing the identity of a substance. Ex: Boiling liquid water. Steam (Vapor) is produced by a gaseous state of water with the same molecular formula as liquid water. Molecules in liquid water and vapor are both made up of two hydrogen atoms and one oxygen. Its identity has not changed. The vapor can be condensed to form liquid water again.

Question 3

Physical Properties of Matter: Mass, Volume, and Density II

Answer 3

Intensive physical properties (density, boiling point) do not depend on the amount of the substance present. Extensive physical properties (mass, volume ) can change depending on the amount of matter present.

Question 4

Mass

Answer 4

Is the specific number of molecules

Question 5

Volume

Answer 5

the amount of space taken up by that number of molecules.

Question 6

Density

Answer 6

Ratio of mass to volume. The ratio is not dependent on the size of the sample but rather the unique structure of the substance. Ex: This means the sample of liquid water has a density of 1 gram per cubic centimeter 1g/cm3 independent of the sample size. Denser substances will sink, whereas less dense substances will float. Ex: Solid water (ice) is less dense than liquid water. This is why ice cubes float in water. Density can be used to identify a substance. Ex: 100 g sample of unidentified metal takes up about 187cm3= 100g/187cm3=0.534g/cm3 This is the density of lithium metal.

Question 7

Gram

Answer 7

Metric unit of mass

Question 8

States of Matter

Answer 8

Molecules make up all matter. Matter exists in four phases: solid, liquid, gas, and plasma. Above absolute zero (0 K or -273C) molecules are constantly in motion.

Question 9

Kinetic Molecular Theory

Answer 9

A theory stating that the molecules that make up all matter are in constant motion, and the temperature of a substance is directly proportional to the average kinetic energy of its molecules. Molecular motion changes as heat is added or removed. Heat overcomes the forces that hold matter together. As the temperature of a substance increases the intermolecular forces that hold molecules together are broken, causing molecules to move away from each other. The amount of heat required for a phase change will not break the bonds within a molecule.

Question 10

Solids

Answer 10

Molecules are packed together in a tight orderly pattern; there is vibrational motion, but no translational motion experienced by the molecules. Solid matter has definite volume and shape. Ex: a solid block of ice. It has a specific number of molecules (matter) and takes up a specifc amount of space. Are not compressible.

Question 11

Liquids

Answer 11

Molecules in liquids are less ordered and exhibit both translational and vibrational motion. Liquid matter has definite volume, but no definite shape, meaning it will conform to the shape of the container. Are not compressible

Question 12

Gas

Answer 12

Gas molecules are rapidly moving and spread far apart. Gas has no definite volume or shape. Gases are highly compressible and subject to changes in volume.

Question 13

Phase of a substance

Answer 13

A phase of a substance depends on two conditions: temperature and pressure. Increasing temperature has a tendancy to move the particles of matter apart, and increasing pressure brings them closer together.

Question 14

Triple Point

Answer 14

Solid, liquid, and gas coexist.

Question 15

Critical Point

Answer 15

Liquid and gas coexist

Question 16

Changes Between States of Matter

Answer 16

Includes solid to a liquid (melting). Boiling a liquid to a gas (Evaporation). Gas to liquid by removing heat (condensation). Solids to gas by (sublimation) a.ka. dry ice. Gas directly converts to a solid by (Deposition).

Question 17

Melting

Answer 17

A change from a solid to a liquid requires an addition of heat, which causes molecules to be more energized. Increaing their vibrational and translational motion. Adding heat (energy) causes the forces holding particles together in a solid state to break.

Question 18

Evaporation

Answer 18

A change from a liquid to a gas. Adding heat is required for this change. Boiling and evaporation are examples of changing from liquid to gas.

Question 19

Condensation

Answer 19

Change from a gas to a liquid. This requires removing heat from matter.

Question 20

Freezing

Answer 20

Change from liquid to solid. This requires the removal of heat.

Question 21

Sublimination

Answer 21

Converts solids to gas. The transition of a substance from solid to gas without passing through the liquid state. Ex: solid carbon dioxide (also known as dry ice). Will change directly from a solid to gas at room temperature.

Question 22

Deposition

Answer 22

The opposite of sublimation where a gas converts to a solid. Ex: in cold temperatures water vapor can directly become solid ice crystals. Forming frost on windows.