chem ch5

Question 1

elements

Answer 1

pure substance that cannot be broken down into 2 or more simpler substances by chemical methods.

Question 2

compound

Answer 2

pure substance contain 2 or more elements chemically combined in a fixed ratio

Question 3

chemical methods compounds can be broken down into

Answer 3

thermal decomposition: strong heat
electrolysis: passing an electric current through the compound

Question 4

Mixture

Answer 4

Two or more elements or compounds that are not chemically combined.
- formed from physical mixing
- no fixed ratio
- same properties to its constituent substances
- melt and boil over a range of temp

Question 5

Ionic compounds

Answer 5

neutral substance made of ions of opposite charges held tgt by ionic bonds

Question 6

alloy

Answer 6

• mixture of a metal with one or more other elements
  -regular arrangement of atoms disrupted by atoms of different sizes.

Question 7

Properties of metals and alloys

Answer 7

Pure metals are malleable: bent w a hammer into a thin sheet
And ductile : pulled into a wire without breaking

Question 8

Metal and alloy mp and bp

Answer 8

Metals have high mp/bp
Alloys do not have fixed melting points as they are mixtures, melt over a range of temperatures.
Both are good conductors of heat

Question 9

Electrical conductivity metals and alloys

Answer 9

Metal atoms have valence electrons that free to move around = can conduct electricity