molecules and matter Flashcards
Density (kg/m3) =
Mass (kg) ÷ volume (m3)
How is the density of a regular object calculated?
Mathematically
How is the volume of an irregular object calculated?
Submerging it in water and measuring the amount of water displaced
Objects that have a lower density than water….
a. float
b. sink
a. float
Describe particles in solids
Strong attractive forces, held in a fixed position, do not compress or flow
Describe particles in a liquid
Moderate attractive forces, always in contact, can move about at random, do not compress but can flow
Describe particles in a gas
Weak attractive forces, move about randomly, can be compressed and flow, least dense.
What happens to the number ofparticles when an object changes state?
Stays the same
What type of substance has a specific melting and boiling point?
A pure substance
Where does boiling occur?
Throughout a substance (at its boiling point)
Where does evaporation occur?
The surface of the liquid (below the boiling point)
Describe changes of state on a temperature time graph
Flat lines
Describe how to allow a substance to
change state
Increasing the temperature increases the internal energy
What is the specific latent heat of vaporisation?
The amount of energy needed to turn 1kg of a substance from liquid to a gas
What is the specific latent heat of fusion?
The amount of energy need to turn 1kg of a substance from a solid to a liquid
Describe what internal energy of a substance is determined by
The kinetic energy of the particles and the potential energy of the particles
Describe gases internal energy
High as the particles have high kinetic energy and high potential energy
What increases the internal energy of the substance?
Increasing the temperature
Describe the cause of the pressure of a gas
Random particles hitting the container or surfaces
Describe how to increase the pressure of a contained gas.
Increasing the temperature as the particles move faster
Describe brownian motion
Random movement of particles can be seen in smoke
When does pressure increase
If volume decreases at a constant temperature
Fixed mass of gas held at a constant temperature calculation
pressure x volume = constant
ρv=constant
