Matter: Properties & Changes

Matter: Properties & Changes

Chapter 2 notesChapter 2 notes

(2.1) Physical Properties of Matter(2.1) Physical Properties of Matter

can be observed or measured without changing the composition of the sample

Examples: color, phase, melting or boiling point, density, hardness, odor, taste

can be observed or measured without changing the composition of the sample

Examples: color, phase, melting or boiling point, density, hardness, odor, taste

States of MatterStates of Matter• Solid (s) - definite volume and shape• Liquid (l) - definite volume, but not shape• Gas (g) - no definite volume or shape• Plasma - highly ionized gas

• Solid (s) - definite volume and shape• Liquid (l) - definite volume, but not shape• Gas (g) - no definite volume or shape• Plasma - highly ionized gas

(s) (l) (g)

sToP & tHinKsToP & tHinK

• Which state or states of matter take(s) the shape of its container?

• Which state or states of matter can change in volume (without adding or subtracting from the sample)?

• Which state or states of matter take(s) the shape of its container?

• Which state or states of matter can change in volume (without adding or subtracting from the sample)?

Physical ChangesPhysical Changes

• Physical changes alter a substance without changing its composition

• Physical changes alter a substance without changing its composition

sToP & tHinKsToP & tHinK1. Which of the following are physical

properties?• liquid at room temperature• reacts with metals to form H2 gas• acids and bases combine to form water and a

‘salt’• boils at 145 degrees Celsius

1. Which of the following are physical properties?• liquid at room temperature• reacts with metals to form H2 gas• acids and bases combine to form water and a

‘salt’• boils at 145 degrees Celsius

(2.2) Mixtures…(2.2) Mixtures…

• Mixture - a combination of two or more pure substances, in which each substance retains its individual chemical properties

• Heterogeneous mixture - does not blend smoothly, individual substances are distinct

• Homogeneous mixture - solution; has a constant composition throughout

• Mixture - a combination of two or more pure substances, in which each substance retains its individual chemical properties

• Heterogeneous mixture - does not blend smoothly, individual substances are distinct

• Homogeneous mixture - solution; has a constant composition throughout

sToP & tHinKsToP & tHinK• Heterogenous or Homogeneous?• Heterogenous or Homogeneous?

(1)

(2)

Separating MixturesSeparating Mixtures• Filtration - porous barrier separates

solid from liquid• Distillation - liquids separated by

differences in boiling point• Crystallization - forms pure solids

from dissolved substances• Chromatography - separation based

on ability to travel or be drawn across a material

• Filtration - porous barrier separates solid from liquid

• Distillation - liquids separated by differences in boiling point

• Crystallization - forms pure solids from dissolved substances

• Chromatography - separation based on ability to travel or be drawn across a material

filtrationfiltration

distillationdistillation

crystallizationcrystallization

chromatographychromatography

sToP & tHinKsToP & tHinKWhat separation technique is shown in the following pictures?

A B

(2.3) Elements & Compounds(2.3) Elements & Compounds

• Elements - pure substances that cannot be broken down into simpler substances– on the Periodic Table!

• Compounds - two or more elements bonded together that can be broken down

• Elements - pure substances that cannot be broken down into simpler substances– on the Periodic Table!

• Compounds - two or more elements bonded together that can be broken down

sToP & tHinKsToP & tHinK1. In your own words, what is the difference

between an element and a compound?2. Classify the following as being elements or

compoundsa) Sodiumb) Sodium chloridec) Oxygend) Carbon dioxidee) Copper

1. In your own words, what is the difference between an element and a compound?

2. Classify the following as being elements or compoundsa) Sodiumb) Sodium chloridec) Oxygend) Carbon dioxidee) Copper

(2.4) Chemical Properties(2.4) Chemical Properties

• the ability of a substance to undergo chemical change

• Examples: “reacts with oxygen to form rust”, “forms a deep blue solution when in contact with ammonia”

• the ability of a substance to undergo chemical change

• Examples: “reacts with oxygen to form rust”, “forms a deep blue solution when in contact with ammonia”

Chemical ChangesChemical Changes• Chemical changes alter the composition

so that a new substance forms• Evidence of chemical change: formation of

a gas or solid (precipitate), smoke, fire, an odor, temperature change, color change– Law of Conservation of Mass:

composition changes, but mass doesn’t

• Chemical changes alter the composition so that a new substance forms

• Evidence of chemical change: formation of a gas or solid (precipitate), smoke, fire, an odor, temperature change, color change– Law of Conservation of Mass:

composition changes, but mass doesn’t

sToP & tHinKsToP & tHinK

• Substance A is a yellow liquid and substance B is a blue liquid. The two are mixed and form a green liquid and a white solid.– What evidence suggests a chemical

change occurred? – What other things could you look for

to determine if there was a chemical change?

• Substance A is a yellow liquid and substance B is a blue liquid. The two are mixed and form a green liquid and a white solid.– What evidence suggests a chemical

change occurred? – What other things could you look for

to determine if there was a chemical change?

sToP & tHinK - which shows physical change and which shows chemical change?

sToP & tHinK - which shows physical change and which shows chemical change?

• link to change animation #1• link to change animation #2

• link to change animation #1• link to change animation #2