ch 1

Question 1

matter

Answer 1

anything that has mass and occupies space

Question 2

pure substance

Answer 2

• only 1 substance present
• constant composition
• properties always same under same conditions

Question 3

element

Answer 3

cannot be broken down into simpler substances by chemical or physical means

ex: gold, silver, copper

Question 4

compound

Answer 4

can be broken down into elements by chemical, not physical means

ex: water (H2O)

Question 5

mixture

Answer 5

• physical combination of 2+ substances

ex: soda, air

Question 6

homogeneous mixture

Answer 6

one visible phase

ex: dissolving salt in water

Question 7

heterogeneous mixture

Answer 7

2+ visible phases, can use physical method to separate

ex: salt + pepper

Question 8

physical properties/changes

Answer 8

• observed without changing ID
• alters appearance, not chem. comp.

ex: color, shape, state, melting/boiling point, hardness
ex: dissolving salt in water

Question 9

chemical properties/changes

Answer 9

• chemical ID/comp. changes –> new substances formed
  ex: flammability, decomposition, reaction w/ another substance
  ex: iron rusting when exposed to moisture/air, burning paper

Question 10

atom

Answer 10

smallest possible unit of an element while retaining properties

Question 11

molecule

Answer 11

group of 2+ atoms bonded together

- diatomic = 2, triatomic = 3, etc.

Question 12

homoatomic

Answer 12

all atoms same kind (i.e. chlorine, phosphorus, sulfur)

Question 13

heteroatomic

Answer 13

2+ different kinds of atoms present