Chapter 2 Section 2 Describing matter Matter anything that has mass and takes up space Mass the amount of matter in something Volume the amount of space something occupies Which of the following is matter ID: 639300
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Slide1
Physical versus Chemical Properties
Chapter 2 Section 2
Describing matterSlide2
Matter: anything that has mass and takes up space
Mass – the amount of matter in something
Volume – the amount of space something occupiesWhich of the following is matter?A car?A box?You?
Reviewing MATTERSlide3
What is a property?
Property
: a characteristic of a substance that can be observedSlide4
Physical Property
Physical property: a property that can be observed without changing the identity of the substance.
Examples: luster
malleability: the ability to be hammered into a thin sheet
ductility: the ability to be stretched into a wire
melting point
boiling point
density
solubility
specific heatSlide5
Physical
Properties
ColorShape Size DensityMelting PointBoiling PointSlide6
Example of Physical Property
The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.
Hardness, color, melting point and density are all physical properties.Slide7
Special Physical Properties
Melting point
: the temperature at which a substance changes from a solid to a liquid at a given pressure water = 0oCBoiling point: the temperature at which a substance changes from a liquid to a gas at a given pressure
water = 100
o
CSlide8
Thermal
Density
Solubility
State
Ductility
MalleabilitySlide9
Chemical Properties
Chemical property
: a property that can only be observed by changing the identity of the substanceSlide10
Chemical Properties
Examples of Chemical Properties
Reactivity with oxygenNonreactivity with oxygenFlammabilityNonflammabilitySlide11
Chemical PropertiesSlide12
Comparison of Physical
and Chemical PropertiesSlide13
Density
Density
is the amount of mass per unit of volume.Density can be used to identify a substance.The density of water is 1.0g/mLSlide14
Density Calculations
Calculations:
D = m/VEx: A cube has a mass of 2.8 g and occupies a volume of 3.67 ml. Would this object float or sink in water?Mass = 2.8 g Volume = 3.67 mLD = 2.8g/3.67 mL
= 0.76 g/
mL
This object would float in water because its density is less than water (1.0 g/
mL
).Slide15
More Density Calculations
Ex: A liquid has a mass of 25.6 g and a volume of 31.6 mL. Use the table below to identify the substance.
M=25.6 g V=31.6 mL
D = 25.6 g/31.6 mL
D= 0.81 g/mL
The substance is ethanol.Slide16
Physical Change
Physical change is the change that affects one or more physical properties of a substance.
Imagine breaking a piece of chalk into two pieces. What are you changing? What is not being changed?Physical changes do not change the identity of the matter involvedSlide17
Physical Change
Freezing water for ice cubes
Sanding a piece of woodCutting your hairCrushing an aluminum canBending a paper clipMixing oil and vinegarSlide18
Chemical Change
Chemical change happens when two or more substance are changed into one or more new substances with different properties.
Properties of a substance describe which chemical changes will or will not happenChemical change and properties are not the same, a change is the process in which it changesSlide19
Chemical Change
Examples of Chemical Changes
Soured milkEffervescent tabletsStatue of LibertyBaking a cakeSlide20
Chemical Change
Clues that chemical change has occurred
Changes in colorHeatFizzing and foamingProduction of sound or light