Physical Properties of Matter
Physical property can be measured and observed without changing the identity and composition of the substance. Some examples of this are color, odor, melting point, boiling point, hardness and density. We can identify the color of a particular substance without changing the identity of the substance.
Physical property can be classified as intensive and extensive properties. Intensive properties are properties that do not depend on the amount of the sample being studied. Example; temperature, melting point and density. Density of water is the same even the amount is changed, let's say a glass of water has 1 g/mL density same with 1 gallon of water. Extensive properties of the substances depend on the quantity of the substance. Example are the mass, length and volume. A glass of water will have different volume with that of a gallon of water. The volume also will change if the amount of the substances will change.
Physical properties can also be classified as intrinsic and extrinsic properties. Intrinsic properties are inherent characteristics of the substance and depend on the kind of the material itself. Some examples are taste, odor, color, transparency, solubility, melting point, boiling point, viscosity, refractive index, hardness, crystalline structure and atomic or molecular diameter. Extrinsic properties are qualities that describe the outside appearance of matter. Examples are size, shape, length, and mass.
Chemical Properties
Chemical properties are properties that can be observed when substance undergo chemical change. For example, hydrogen gas burns in the presence of oxygen gas forming water. Meaning combustibility of the substance is an example of chemical properties and this can be observed when a chemical reaction occur. Another chemical properties include toxicity, flammability, chemical stability, enthalpy of formation, reactivity with other chemicals.
Physical Change and Chemical Change
Change can be classified as physical change and chemical change. During physical change the substance only undergoes change in the physical appearance, but not the composition. Example is the evaporation of liquid water to water vapor. The change only undergoes change in state from liquid to gas state but still the composition is still the same water. All changes in state are all physical change.
Chemical change is a change in which the substance undergoes change in its composition. Meaning a new substance is formed during the process. Example, combustion of carbon forms carbon dioxide. Combustion is the reaction of substance with oxygen, meaning carbon reacts with oxygen forming carbon dioxide. This is an example of chemical change because the reactants carbon and oxygen have their own unique properties and once they react with each other the new substance carbon dioxide has different properties different from its origin.
Let us answer the following:
1. Which of the following properties are extensive and intensive?
a. length
b. volume
c. boiling point
d. color
e. density
2. Identify the property if physical or chemical
a. oxygen gas supports combustion
b. fertilizer help to increase agricultural production
c. water boils below 100oC on top of the mountain
d. lead is denser than aluminum
e. uranium is a radioactive element
3. Classify if physical change or chemical change
a. The helium gas inside a balloon leaks out of the container after few hours.
b. A flashlight beam slowly gets dimmer and finally goes out
c. dissolving sugar in water
d. boiling of water
e. heating of sugar
Answer's Key
1. a. length - extensive
b. volume - extensive
c. boiling point - intensive
d. color - intensive
e. density - intensive
2. a. chemical properties
b. chemical properties
c. physical properties
d. physical properties
e. chemical properties
3. a. physical change
b. chemical change
c. physical change
d. physical change
e. chemical change
No comments:
Post a Comment