Matter & Chemical Change

Question 1

What are the two types of matter?

Answer 1

1. Pure substances
2. Mixtures

Question 2

What type of mixture is Homogeneous? Heterogeneous?

Answer 2

Homogeneous: solutions & colloids
Heterogeneous: mechanical mixtures & suspensions

Question 3

What are the two types of pure substances?

Answer 3

1. an element
2. a compound

Question 4

What is an element?

Answer 4

a pure substance made entirely of one type of atom

Question 5

What is the basic structure of an atom?

Answer 5

in the center, there is a nucleus that holds protons and neutrons. orbiting the outside, there are electrons

Question 6

What is a compound?

Answer 6

a pure substance that is made up of one or more atoms

Question 7

What is a mechanical mixture?

Answer 7

A heterogeneous combination of two or more substance that simply will not mix
Ex: mixed veggies

Question 8

What is a solution? Will the components separate overtime? Can they be separated by filtration?

Answer 8

homogeneous mixtures of a solute dissolved in a solvent
-they will NOT separate overtime
-can NOT be separated by filtration
Ex: iced tea

Question 9

What is a suspension? Will the components separate overtime? Can they be separated by filtration?

Answer 9

a heterogeneous mixture in which insoluble particles are suspended in a liquid or gel.
-they WILL separate over time
-the solids CAN be separated by filtration
Ex: orange juice with pulp

Question 10

what is a colloid? Will the components separate overtime? Can they be separated by filtration?

Answer 10

a homogeneous type of suspension, but solid particles are finer
-they WONT separate overtime
-they WONT separate through filtration
Ex: milk

Question 11

What is a chemical reaction?

Answer 11

When substances react with each other to form products with different chemical properties
Ex: hydrogen gas reacting with oxygen gas to form liquid water
2 H2(g) + O2(g) —> H2O(l)

Question 12

what is the definition of properties?

Answer 12

to describe the physical appearance and composition of a substance

Question 13

what are examples of physical properties?

Answer 13

-boiling point
-ductility (can be turned to wire)
-malleability (can be pounded into a sheet)
-state
-solubility
-conductivity
-color

Question 14

define chemical properties

Answer 14

to describe the reactivity of a substance

Question 15

what are examples of chemical properties?

Answer 15

-ability to burn
-odor
-behaviour with air
-behaviour with water
-reaction with acids
-reaction to heat
-reaction to red & blue litmus paper

Question 16

What are the difference between chemical and physical properties?

Answer 16

physical:
-no new substance produced
-change of location
-changes state only
-may be easily reversed
chemical:
-precipitate produced (solid formed)
-heat or light produced
-gas produced
-new color
-new odor
-not reversible by physical means

Question 17

what did Aristotle believe?

Answer 17

believed all matter was composed of combinations of fire, earth, air, and water

Question 18

what did John Dalton believe?

Answer 18

-Billard ball model
-all matter is made up of small particles called atoms
-atoms of different elements have different properties

Question 19

what did Neils Bohr believe?

Answer 19

electrons travel around the nucleus in discrete levels

Question 20

what did Democritus believe?

Answer 20

proposed that matter was made of tiny particles called “atomos,” meaning invisible

Question 21

What did J.J. Thompson believe?

Answer 21

-plum pudding model
-atom was a sphere with a positive charge embedded with negative particles

Question 22

what did Ernest Rutherford believe?

Answer 22

atom had a tiny positively charged nucleus

Question 23

what did Nagaoka believe?

Answer 23

electrons outside sphere, like the rings of saturn