science unit test

Question 1

base

a chem that produces a basic substance, h a ph v o m t 7

Answer 1

a chemical that produces a basic substance, having a pH value of more than 7

Question 2

catalyst

Answer 2

a substance that speeds up chemical reactions but are not in them

Question 3

caustic

Answer 3

an agent that burns or destroys living tissue

Question 4

chemical change

Answer 4

a change where one or more new chemical substances are formed

Question 5

chemical family

Answer 5

groups of elements that have similar properties

Question 6

chemical property

Answer 6

a characteristic of matter that describes how it reacts when undergoing a chemical change (e.g., reaction of a substance with electricity)

Question 7

chemical reaction

Answer 7

two or more substances have a reorganization and form new substances

Question 8

chronic toxicity

Answer 8

the ability of a chemical to cause harm to an organism only after the chemical has been exposed to the organism repeatedly or for a long time

Question 9

colloids

Answer 9

heterogeneous mixtures made up of fine particles evenly distributed throughout

Question 10

combustion

Answer 10

the highly exothermic combination of a substance with oxygen; requires heat, oxygen, and fuel

Question 11

corrosion

c

Answer 11

a process where metals or stone are chemically broken down

Question 12

Dalton’s atomic theory

Answer 12

states that: The first part of his theory states that all matter is made of atoms, which are indivisible.
The second part of the theory says all atoms of a given element are identical in mass and properties.
The third part says compounds are combinations of two or more different types of atoms.
The fourth part of the theory states that a chemical reaction is a rearrangement of atoms.

Question 13

density

Answer 13

amount of matter that occupies a certain space; the mass per unit volume of a substance

Question 14

diatomic molecules

Answer 14

molecules made of two atoms of the same element\

Question 15

electrons

Answer 15

negatively charged particles

Question 16

element

Answer 16

a pure substance made up of one type of particle, cannot be broken down into simpler substances by means of a chemical change

Question 17

element symbols

Answer 17

one or more letters used to represent the name of a substance (e.g., O is the symbol for oxygen)

Question 18

emulsions

Answer 18

types of colloids in which liquids are dispersed in liquids

Question 19

endothermic reaction

Answer 19

a chemical reaction in which heat energy is taken in from the surroundings

Question 20

experiment

Answer 20

an activity or procedure designed to test a hypothesis

Question 21

exothermic

Answer 21

a chemical reaction in which heat energy is released to the surroundings

Question 22

gas

Answer 22

the state of matter in which a substance has neither a definite shape nor a definite volume (e.g., water vapour)

Question 23

hazardous

Answer 23

containing substances that are poisonous, corrosive, flammable, or explosive

Question 24

heterogeneous mixture

Answer 24

a mixture in which the particles are not uniformly scattered; does not have a uniform composition

Question 25

homogeneous mixture

Answer 25

a mixture in which particles are uniformly scattered; has a uniform composition

Question 26

hypothesis

Answer 26

a statement of a proposed relationship, based on background information or an observed pattern of events, and stated in a way that makes it testable.

Question 27

indicator

Answer 27

a chemical that changes colour to indicate whether a substance is an acid or a base

Question 28

ionic compound

Answer 28

formed when atoms transfer electrons to or from other atoms

Question 29

law of conservation of mass

Answer 29

in a chemical change, the total mass of the new substances is always the same as the total mass of the original substances

Question 30

law of definite composition

Answer 30

compounds are pure substances that contain two or more elements combined together in definite proportions

Question 31

liquid

Answer 31

the state of matter in which a substance has a definite volume, but no definite shape (e.g., water)

Question 32

manipulated variable

Answer 32

in an experiment, a factor that is selected or adjusted to see what effect the change will have on the responding variable

Question 33

mass

Answer 33

the amount of matter in a substance

Question 34

mass number

Answer 34

the total number of protons and neutrons in the nucleus

Question 35

melting

Answer 35

the process of changing from solid to liquid

Question 36

melting point

Answer 36

the temperature at which a solid changes to a liquid

Question 37

metalloids

Answer 37

elements with properties in between metals and nonmetals

Question 38

mixture

Answer 38

a combination of two or more pure substances such that each one's properties are not lost, but may be hidden

Question 39

molecular compound

Answer 39

formed when atoms share electrons

Question 40

molecule

Answer 40

smallest independent unit of a pure substance, generally a cluster of atoms joined together

Question 41

particle model of matter

Answer 41

a scientific model of the structure of matter; one part of this theory states that all matter is made up of extremely small particles

Question 42

pH paper

Answer 42

paper saturated with a chemical to show whether a substance is acidic or basic

Question 43

pH scale

Answer 43

a scale that measures the acidity or alkalinity of a substance

Question 44

physical change

Answer 44

change in form but not in chemical composition; no new substances are formed

Question 45

products

Answer 45

the substances produced by a chemical reaction

Question 46

properties

Answer 46

characteristics that describe matter

Question 47

atomic nucleus the centre of the atom; contains the protons and neutrons

Question 48

atomic number the number of protons in the nucleus of an atom

Question 49

its time for bed

Answer 49

i hate science