P6 MOLECULES AND MATTER Flashcards
The density of a substance of a substance is defined….
as its mass per unit volume
Density,p(kg/m^3) =
Mass,m/Volume(m^3).p=m/volume
How to measure density of a solid or a liquid?
Measure its mass and its volume the use p=m/v
Objects that have lower density than water…
float in water.
When a substance changes state, its mass stays the same because…
The number of particles stays the same.
The flat section of a temperature time graph presents what?
The melting or boiling point of the substance.
Increasing the temperature of a substance…
Increases its internal energy.
What does the strength of the forces of attraction between the particles of a substance explain?
Why it is a solid, liquid or gas.
What happens when a substance is heated and its temperature rises?
The kinetic energy of its particles increases.
What happens when a substance is heated and it melts or boils?
The potential energy of its particles increases
The pressure of a gas on a surface is caused by?
The particles of the gas repeatedly hitting the surface.
the pressure of a gas is caused by…
The random impacts of gas molecules on surfaces that are in contact with the gas.
Why does the temperature of a gas sealed in a container increase the pressure of the gas?
The molecules move faster so they hit the surface with more force and the number of impacts per second increases in the container.
