Kinetic Model Of Matter Flashcards
Why can’t solids be compressed?
The molecules are arranged close together in a regular pattern and there is little space between them
Why can’t liquids be easily compressed?
The molecules are close together and there is little space between them
What is the motion of molecules in a solid?
There are balanced forces holding them in fixed positions.
The molecules can only vibrate about their fixed positions, alternately repelling and attracting one another
What is the motion of molecules in the liquid?
Molecules also vibrate to and fro, alternate attracting and repelling one another
Though there are still forces the molecules are not held in fixed positions. Hence they are free to flow and take the shape of the container
Why do solids have fixed shapes and volumes?
Strong attractive forces prevent the molecules from leaving the positions while repulsive forces which act when they are too close prevent the solid from collapsing
Why are gases easily compressed?
The molecules are sparse and there is a lot of space between them
What is the motion of gas molecules?
The molecules move randomly at high speeds, colliding with one another and with the walls of of the container
Why do gases have no fixed shape?
Intermolecular forces act only at moments of collision. Otherwise, the molecules are so far apart that intermolecular forces become negligible. Hence a gas is free to fill a container completely
Define Brownian motion
Brownian motion is the haphazard movement of microscopic particles suspended in a fluid (liquid or gas) due to the uneven bombardment of the suspended particles by the molecules of the fluid
State what is meant by kinetic model of matter
The kinetic model of matter is made up of a large number of tiny atoms or molecules which are in constant random motion
Why does increase in temperature lead to increase in kinetic energy?
The surrounding air molecules are moving faster and hitting particles more frequently with more force
The thermal energy is then transferred to molecules of the fluid, which gain kinetic energy and move more vigorously
Motion of molecules and pressure
When randomly moving gas molecules hit the wall of a container, they exert a force on the wall giving rise to gas pressure
Pressure temperature relationship in gases
For a fixed mass of gas at constant volume, when the temperature increases, molecules move faster and hit the walls more frequently and more violently
For a fixed mass of gas at constant volume, gas pressure increases with gas temperature and vice versa
Volume temperature relationship in gases
Volume of a fixed mass of gas at constant pressure increases with temperature
Pressure volume relationship in gases
For a fixed mass of gas at constant temperature average speed of molecules remains the same
Volume is inversely proportional to pressure
