Science unit 1

Question 1

What is matter

Answer 1

matter is anything that takes up space

Question 2

What are the two types of pure substances

Answer 2

elements and compounds

Question 3

What is an element

Answer 3

only one type of atom

Question 4

What is a compound

Answer 4

two or more types of atoms; e.x. H2O

Question 5

What is a mixture

Answer 5

a substance that contains more than one type of particle

Question 6

What is a heterogeneous mixture

Answer 6

(mechanical mixture) A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. (you can see the different components)

Question 7

What is homogeneous mixture

Answer 7

(solutions): A homogeneous mixture is a mixture in which the composition is uniform and looks like one throughout the mixture.

Question 8

What is a alloy

Answer 8

an alloy is a type of solution composed of two or more metals

Question 9

examples of alloys

Answer 9

-Bronze=copper+tin
-Steel=Iron+carbon
-Brass=Copper+zink

Question 10

What are physical properties

Answer 10

a characteristic of a substance that can be determined using observations we make

Question 11

what is a qualitative observation

Answer 11

observations made using our five senses (sight, smell, taste, touch, and sound)

Question 12

What is a quantitative obstervation

Answer 12

observations made by measuring and has a numerical value

Question 13

What is lustre

Answer 13

shininess of an object

Question 14

What is optical clarity

Answer 14

the ability to allow light through (i.e. transparent, translucent, opaque)

Question 15

What is brittleness

Answer 15

tendency to break/crack

Question 16

What is viscosity

Answer 16

the ability of a substance flow or pour readily

Question 17

What is hardness

Answer 17

the ability to be scratched by another substance

Question 18

what is malleability

Answer 18

the ability to be hammered into a thinner sheet or molded

Question 19

What is ductility

Answer 19

the ability to be drawn (pulled) into a wire

Question 20

what is electrical condutivity

Answer 20

the ability to conduct electricity

Question 21

What are physical changes

Answer 21

a change in a substance that does not alter its composition (The particles in a physical change do not change); usually reversible

Question 22

What are characteristic physical properties

Answer 22

characteristic physical properties can be used to identify a substance.
These include: solubility, freezing point, melting point, boiling point, and density.

Question 23

what is freezing point

Answer 23

temperature a substance turns from liquid to solid

Question 24

what is melting point

Answer 24

temperature a substance turns from solid to liquid (same temperature as freezing point)

Question 25

what is boiling point

Answer 25

temperature a substance turns from liquid to gas

Question 26

what is density

Answer 26

the degree of compactness of a substance. (d=m/v)

Question 27

what are chemical properties

Answer 27

a property of a substance that describes its ability to undergo changes to its composition to produce one or more new substances

Question 28

Examples of chemical properties

Answer 28

-Flammability - ability to burn at room temperature -Combustibility - ability to burn at a raised temperature -Toxicity - ability to poison -Corrosivity - ability to corrode or eat away

Question 29

What is a chemical change

Answer 29

a change in the composition of a substance that results in one or more new substances

Question 30

What are the five clues of chemical chanage

Answer 30

-Colour change -Change in odour -Bubbles of gas form -Precipitate formed (solid that separates from solution) -Change in temperature/ light produced (at least one change must occur to consider it a chemical change)

Question 31

Who is Democritus

Answer 31

A Greek philosopher 400 BCE propose matter, was composed of small indivisible blocks of various shapes, and sizes. Named this particle the atom which means "cannot cut”

Question 32

Who was Aristotle

Answer 32

Greek philosopher 450 BCE. Rejected the concept of the atom supported an earlier theory of all matter is made up of four substances: earth, water, air, and fire.

Question 33

Who was John dalton

Answer 33

John Dalton, 1807. Proposed the “ billiard ball model”. His main ideas were 1 all matter is made up of atoms 2 Atoms of an element are identical 3 different elements have different atoms 4 Adams can be rearranged to form new substances, but can’t be created or destroyed.

Question 34

Who was JJ Thompson

Answer 34

JJ Thompson 1897. Discovered the electron using cathode ray tube experiment. Adams contain negatively charge particles called electrons, embedded in a positively charge sphere. Called it the plum pudding model.

Question 35

Who was Ernest Rutherford

Answer 35

Ernest Rutherford, 1909, 1920. Discovered the nucleus in 1909, using his gold foil experiment. Nucleus is very small, but dense centre of the atom surrounded by empty space. Nucleus is surrounded by electrons and is positively charged. Discovered protons in 1920.

Question 36

What was the gold foil experiment

Answer 36

Fire positively charged particles at a piece of gold foil. Some particles bounce right back. So Rutherford concluded that there were very small, but dense center of the atom that must be positively charge called the nucleus

Question 37

Who was James Chadwick

Answer 37

James Chadwick, 1932. Proposed that the nucleus must contain neutral particles called neutrons that make up portions of the atoms mass. Determined the mass of a proton equals the mass of a neutron.

Question 38

Who was Neil’s Bohr

Answer 38

Neil Bohr , 1913. Conducted experiments with the hydrogen atoms and the light it produce when electricity runs to it. Bohr propose the following: electrons orbit, the nucleus, orbits can hold surgeon numbers of electrons, the further and electron is from the nucleus the more energy, electrons return back to their original orbits and release energy as light.

Question 39

Why do elements form compounds

Answer 39

Adams are not stable if they’re highest i.e. last shells do not have the maximum number of electrons.