Chapter 6: Molecules And Matter Flashcards
What is the equation for density?
Density = mass/ volume (kg/m3)
What is the density triangle?
Mass top
Density bottom left
Volume bottom right
What happens if an object has a lower density than water?
It floats on the water
Describe the particles of a solid
The particles of a solid are held next to each other in fixed positions. They are the least energetic of the states of matter. They have a fixed shape and a fixed volume. They have the lowest kinetic energy of the three states of matter. They don’t move around and only vibrate, they cannot be compressed .
Describe the particles of a liquid
The particles in a liquid move around at random and are in contact with each other, they are more energetic than the particles in a solid. They have the second highest kinetic energy, they move around freely but must remain within a defined space/volume. They flow and move past each other. They cannot be compressed.
Describe the particles in a gas
They move about randomly and are far apart so gases are much less dense than solids and liquids. They are the most energetic and have the highest kinetic energy of all the states of matter. They move around freely without a defied space/volume. They can be compressed
What happens to the mass when particles change state?
Its mass stays the same because the number of particles stays the same
What is a pure substances melting point defined as?
Its melting point is the temperature at which it melts.
It is the same temperature that it solidifies
What is a pure substances boiling point point defined as?
Its boiling point is the temperature at which it boils.
It is the same temperature at which it condenses.
What is boiling?
It occurs throughout the liquid at its boiling point.
What is evaporation?
Evaporation occurs from the surface of a liquid when its temperature is below boiling its boiling point
What happens to a substances temperature when it is changing state?
It stays the same
Wat does the flat section of a temperature time graph tell you?
It gives the melting point or the boiling point of a substance
What is the difference between boiling and evaporation?
Evaporation happens at any temperature, boiling only happens at the substances boiling point
What happens when you increase the temperature of a substance?
It increases the substances internal energy and the kinetic wnegy of its particles increases.
What happens to the energy of the substance when it melts or boils
If it melts or boils the potential energy of its particles increases
What causes the pressure of a gas?
The pressure of a gas on a surface is caused by the particles of the gas repeatedly hitting the surface of the container
What is latent heat?
It is the energy needed for a substance to change its state without changing its temperature
What is specific latent heat of fusion?
Is the energy needed to melt 1kg of substance without changing its temperature
What is the specific latent heat of vaporisation?
Is the energy needed to boil 1kg of a substance without changing its temperature
What is the internal energy of a substance?
It is the combination of the movement and position of the particles.
The kinetic energy they have due to movement + the potential energy they have due to their position = internal energy
What is the equation triangle for latent heat of fusion?
Energy top (J)
Latent heat bottom left (J/kg)
Mass bottom right (kg)
Remember Elf massacre
What is the triangle for latent heat of vaporisation?
Energy top (J)
Latent heat bottom right (J/kg)
Mass bottom left (kg)
Remember elven massacre
What happens if the temperature of a gas in a sealed container increases?
The pressure increases
