
Properties of matter are mass, volume, and density, describe how substances occupy space and respond to external stimuli; they form the basis for classifying materials into solids, liquids, and gases. Measurement of these properties employs standardized units—kilograms for mass and cubic meters for volume—to ensure consistency and comparability across scientific investigations. Properties of matter are classified as physical (observable without changing composition) or chemical (related to reactivity). Accurate measurement using SI units ensures consistency in scientific calculations.
The study of matter's properties dates to ancient civilizations, with Indian alchemists in texts like the Charaka Samhita measuring densities for medicinal compounds. The SI system, formalized in 1960, standardized measurements, replacing earlier systems like cgs. Lavoisier's work on mass conservation (18th century) underscored precise measurement, critical for JEE-level calculations.
Students should practice the NCERT Solutions of Some Basic Concepts of Chemistry Chapter to ensure that they can write well in the CBSE board exam and pass with flying colours.
- Physical and Chemical Properties
- SI Units and Measurement
- Mass and Weight
- Volume
- Density
- Temperature
- JEE-Level Examples
- Common Mistakes
- Key Points
- Conclusion
Physical and Chemical Properties
Physical properties, such as mass, volume, density, and melting point, can be measured without altering a substance's chemical identity. Chemical properties, like reactivity with acids or flammability, describe a substance's ability to undergo chemical changes. For example:
1. Physical: Density of water .
2. Chemical: Iron reacts with oxygen to form rust .
JEE questions may require identifying properties or using physical properties in calculations.
SI Units and Measurement
The International System of Units (SI) standardizes measurements with seven base units: meter (m, length), kilogram (kg, mass), second (s, time), kelvin (K, temperature), mole (mol, amount of substance), ampere (A, electric current), and candela (cd, luminous intensity). Derived units, like density ( ), are combinations of base units. SI prefixes (e.g., kilo- , milli- ) simplify large/small quantities. JEE problems often involve unit conversions, such as converting to :
Mass and Weight
\Mass is the amount of matter in a substance (kg), invariant across locations. Weight is the force exerted by gravity on mass (N), varying with gravitational field strength ( ).
Mass is measured using balances (e.g., analytical balance, precision to 0.0001 g ). Example: A 2 kg object has weight:
JEE MAIN and NEET exam numericals test mass-weight distinctions and conversions.
Volume
Volume is the space occupied by matter ( or L , where ). It is measured using graduated cylinders, pipettes, or burettes, with precision to 0.1 mL for graduated cylinders. Conversion example:
JEE problems involve volume calculations in gas laws or solution chemistry.
Density
Density is mass per unit volume ( or ):
Example: A 10 g object with volume has density:
Density is temperature-dependent (liquids expand with heat).
JEE questions may require density-based calculations, such as determining mass from volume.
Temperature
Temperature measures the degree of hotness or coldness, expressed in kelvin (K). Celsius ( ) is also used, where:
Fahrenheit ( ) conversion:
Example: . Thermometers (mercury or digital) measure temperature.
JEE problems involve temperature conversions in gas laws or thermochemistry.
JEE-Level Examples
Example 1: A metal block has a mass of 250 g and volume of . Calculate its density in . (JEE Main)
Convert units:
Example 2: Convert a gas volume of 2.5 L at to at 300 K . (JEE Main) Volume in :
Since volume is temperature-dependent :
(Note: Same temperature implies no change, but JEE tests such conversions.)
Common Mistakes
Key Points
Conclusion
Chemistry Some Basic Concepts of Chemistry Exam
Student Forum
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