# Properties of Matter and their Measurement

Properties can be classified in to two types
1. Physical properties
2. Chemical properties

# Physical properties

Definition
The properties which can be measured or observed with out changing the identity or the composition of the substance is called physical properties

Examples
colour, odour, melting point, boiling point, density etc.

# Chemical properties

Definition
The properties which require chemical change is called chemical properties. Chemical properties are characteristic reactions of different substances.

Examples
Acidity or basicity, combustibility

There are two different systems of measurement
1. The English system
2. The Metric system

# Mass and weight

Definition
The amount of matter present in a substance is called mass of a substance.

Weight is the force exerted by the gravity on an object.

Mass of a substance is constant. Weight may vary from place to place due to gravity.

Mass of a substance can be determined very accurately.

SI unit for mass - kilogram

# Volume

The unit for volume - (length)3

In SI system unit is - m3

In laboratories only smaller volumes are used. Hence, volume is often denoted in cm3 or dm3 units.

# Density

Density of a substance is its amount of mass per unit volume

So, SI units of density can be obtained as follows

SI unit of density = SI unit of mass

SI unit of volume

= kg/m3 or kgm-3

This unit is quite large and a chemist often expresses density in gcm-3, where mass is expressed in gram and volume is expressed in cm3.

# Temperature

There are three common scales to measure temperature
1. 0C (degree Celcius)
2. 0F (degree Fahrenheit)
3. K (Kelvin)
Here, K is the SI unit.
1. Generally, the thermometer with Celsius scale are calibrated from 0oC to 1000 where these two temperatures are the freezing point and the boiling point of water respectively
2. The Fahrenheit scale is represented between 320 to 2120
The temperatures on two scales are related to each other by the following relationship
0F = 9/5 (0C) + 32
The Kelvin scale is related to Celsius scale as follows
K = 0C + 273.15

Important points
• Temperature below 00C are possible in Celsius scale
• In Kelvin scale, negative temperature is not possible.