Chemistry: Unit 2

Question 1

Chemistry

Answer 1

it is the branch of science that deals with the identification of the substances of which matter is composed. And deals with the different properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.

Question 2

Matter

Answer 2

Matter is defined as anything that has mass and takes up space.

Question 3

Extensive Properties

Answer 3

Extensive properties, such as mass and volume, depend on the amount of matter being measured.

Question 4

Intensive Properties

Answer 4

Intensive properties, such as density and color, do not depend on the amount of the substance present.

Question 5

Mass

Answer 5

Mass is a measure of the amount of matter in an object. Mass is usually measured in grams (g) or kilograms (kg)

Question 6

Volume

Answer 6

Volume is the quantity of three-dimensional space occupied by a liquid, solid, or gas. Common units used to express volume include liters, cubic meters, gallons, milliliters, teaspoons and ounces.

Question 7

Physical Property

Answer 7

Physical properties can be measured without changing a substance’s chemical identity.

Question 8

Physical Change

Answer 8

Any change that occurs without altering the chemical composition of a substance is a physical change. Physical changes can include changing the color, shape, state of matter, or volume of a substance.

Question 9

Chemical Property

Answer 9

A property or characteristic of a substance that is observed during a reaction in which the chemical composition or identity of the substance is changed

Question 10

Chemical Change

Answer 10

This is usually a irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance

Question 11

Phase (Phase of Matter)

Answer 11

It is a phase that is physically distinctive form of matter, such as a solid, liquid, gas or plasma. A phase of matter is characterized by having relatively uniform chemical and physical properties.

Question 12

Solid

Answer 12

A solid is a state of matter characterized by particles arranged such that their shape and volume are relatively stable.

Question 13

Liquid

Answer 13

A liquid is one of the states of matter. The particles in a liquid are free to flow, so while a liquid has a definite volume, it does not have a definite shape. Liquids consists of atoms or molecules that are connected by intermolecular bonds

Question 14

Gas

Answer 14

The atoms or molecules in gases are more widely spaced than in solids or liquids and suffer only occasional collisions with one another.

Question 15

Freezing

Answer 15

The process through which a substance changes from a liquid to a solid.

Question 16

Melting

Answer 16

Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid.

Question 17

Vaporization

Answer 17

it is the conversion of a solid or a liquid into a gas.

Question 18

Condensation

Answer 18

Condensation is the process of a substance in a gaseous state transforming into a liquid state.

Question 19

Sublimation

Answer 19

Sublimation is a type of phase transition, or a change in a state of matter, just like melting, freezing, and evaporation

Question 20

Deposition

Answer 20

Deposition is a process where a gas changes phase and turns directly into solid without passing through the liquid phase.

Question 21

Substance (Pure Substance)

Answer 21

Pure substances are defined as substances that are made of only one type of atom or molecule

Question 22

Element

Answer 22

An element is composed of atoms that have the same atomic number, that is, each atom has the same number of protons in its nucleus as all other atoms of that element.

Question 23

Chemical Symbol

Answer 23

it is the symbols in the periodic table. Natural elements all have chemical symbols of one or two letters;

Question 24

Compound

Answer 24

A compound is a substance formed when two or more chemical elements are chemically bonded together

Question 25

Mixture

Answer 25

Any substance that has a uniform and unchanging composition that is considered to be pure.

Question 26

Homogeneous Mixture

Answer 26

An example of a homogeneous mixture is air. In physical chemistry and materials science that refers to substances and mixtures which are in a single phase. This is in contrast to a substance that is heterogeneous.

Question 27

Solution

Answer 27

a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent.

Question 28

Heterogeneous Mixture

Answer 28

A mixture is a combination of two or more pure substances in which the original substances retain their chemical properties. In some mixtures, the initial substances cannot be detected after they have been mixed.

Question 29

Filtration

Answer 29

Filtration is any of various mechanical, physical or biological operations that separate solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass. The fluid that passes through is called the filtrate.

Question 30

Distillation

Answer 30

Distillation can be used to purify water or other substances, or to remove one component from a complex mixture, as when gasoline is distilled from crude oil or alcohol from a mash

Question 31

Chemical Reaction

Answer 31

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products

Question 32

Reactant

Answer 32

The raw materials that react with each other are known as reactants.

Question 33

Product

Answer 33

The substances that result from this recombination of atoms are called the products of the reaction.

Question 34

Precipitate

Answer 34

it causes a substance to be deposited in solid form from a solution.

Question 35

Law of Conservation of Mass

Answer 35

The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.