1. Physical and Chemical Properties and Changes
January 2011
GPS Standards: SC1. Students will analyze the nature of matter and its classifications.
Identify substances based on chemical and physical properties.
SCSh5. Students will demonstrate the computation and estimation skills necessary for analyzing data and developing reasonable scientific explanations.
e. Solve scientific problems by substituting quantitative values, using dimensional analysis and/or simple algebraic formulas as appropriate.

2. physical property = characteristic of a substance that can be observed or measured WITHOUT changing the identity (chemical formula) of the substance. Most physical properties do NOT depend on the size or source of the sample.
chemical property: characteristic of a substance that can be observed or measured only by performing a chemical reaction with the substance (the reaction causes a CHANGE in the substance’s formula). Most chemical properties do NOT depend on the size or source of the sample.
physical change = a change in the physical form or properties of a substance that occurs WITHOUT changing the identity (formula) of the substance.
chemical change = a CHANGE in the chemical formula of a substance that occurs through a chemical reaction, forming one or more new substances.

3. Physical Properties Physical Changes Chemical Changes
Chemical Properties
Physical Changes
Chemical Changes
density
flammability
fruit ripening
batteries “dying”
boiling
color
boiling point
breathing
burning
precipitates forming
neutralization
shape
reactivity
shape/texture change
sublimating
volume
condensing
decomposition rate
density
flammability
color
reactivity
boiling point
decomposition rate
shape
volume
boiling
fruit ripening
shape/texture change
batteries “dying”
sublimating
breathing
condensing
burning
precipitates forming
neutralization

4. Physical Properties Physical Changes Chemical Changes
Chemical Properties
Physical Changes
Chemical Changes
deposition
changing mass/volume
melting point
phase
color change
acid/base character
colored paper fading
melting
photosynthesis
dissolving
electrical conductivity
evaporating
hardness
magnetic character
mass
density
flammability
magnetic
character
color
reactivity
boiling point
decomposition rate
mass
shape
acid/base character
volume
melting point
phase
electrical conductivity
hardness
boiling
fruit ripening
shape/texture change
batteries “dying”
sublimating
breathing
condensing
burning
deposition
precipitates forming
changing mass/volume
neutralization
melting
color change
dissolving
colored paper fading
evaporating
photosynthesis

5. Properties can also be classified another way:
extensive properties: depend on amount of matter that is present in the sample. Can be physical or chemical.
examples = mass, volume, some chemical reactivities, etc.
intensive properties: do NOT depend on amount of matter that is present in the sample. Can be physical or chemical.
examples = melting/boiling points, density, hardness, electrical conductivity, magnetism, color, shape, reactivity, combustibility, acid/base character, etc.

6. Density
density (D) = the relationship between the mass (m) and volume (V) of a substance.
acceptable units for mass include grams (g), kilograms (kg), etc.
acceptable units for volume include cubic centimeters (cm3), liters (L), milliliters (mL), etc.
acceptable units for density include g/cm3, g/L, g/mL, kg/L, etc.
the volume measurement of a density problem can calculated in two ways:
water displacement = method for measuring the volume of an irregular object.
an object is dropped into a measured amount of water in a graduated cylinder or beaker.
D = m V

7. water displacement = method for measuring the volume of an irregular object.
an object is dropped into a measured amount of water in a graduated cylinder or beaker.
the difference between the initial volume of the water and the new volume of the water is equivalent to the object’s volume.
measured size = method for measuring the volume of a regular object (such as a rectangular prism, sphere, or cylinder) by measuring the length of the sides/radius.
practice problems:
Ex1: If g of a liquid occupy a space of 44.5 mL, what is the density of the liquid in g/cm3?

8. 1 mL = 1 cm3 ...so 44.5 mL = 44.5 cm3 D = m V = 15.68 g = 44.5 cm3
Ex1: If g of a liquid occupy a space of 44.5 mL, what is the density of the liquid in g/cm3?
D = _____________
m = _____________
V = _____________
Ex2: The density of silver is g/cm3.  If small bar of pure silver measures 3.4 cm by 1.8 cm by 3.7 cm, what would the mass be for this sample? ?
15.68 g
44.5 mL
1 mL = 1 cm3
...so 44.5 mL = 44.5 cm3
D = m V
= g =
44.5 cm3
.35 g/cm3
10.49 g/cm3 ?
cm3
V = lwh
= (3.4 cm)(1.8 cm)(3.7 cm)
V = cm3
V  V
D = m V
m = VD =
( cm3)(10.49 g/cm3) = g

9. __ ___ D D m = VD V = m D 11.34 g/cm3 364.5 g ? V = 364.5 g =
Ex3: The density of a lead cylinder is g/cm3.  What would be the length of a g cylinder of this metal if its radius is 2.7 cm?
D = _____________
m = _____________
V = _____________
__ ___
D D
m = VD
V = m D
11.34 g/cm3
364.5 g ?
V = g =
11.34 g/cm3
32.14 cm3
V = r2h
__ _____
r r2
h = V =
r2
32.14 cm3 =
(2.7 cm)2
1.40 cm