P6 Flashcards
The equation for density (rho) is
Mass (m) (kg) / volume (v) (m3)
What does the density of an object depend on?
What its made of and how its particles are arranged
If you compress an object, what will happen to the arrangment of the particles?
The particles woukd move closer together, and it would become more dense but you wouldn’t be decreasing its volume.
Describe the characteristics of a liquid
LIQUID: there is weaker forces of attraction between particles. The particles are flose together, but can move past each other in irregular arrangments. They have more energy than the particles in a solid - move in random directions at low speeds. Generally less dense than solids
Desribe the characteristics of solids
Strong forces of attraction hold the particles close together in a fixed, regular arrangement.
The particles don’t habe much energy so they can only vibrate about their fixed positions. The density is generally highest in this state as the particles are closest together.
Liquid to solid is
Freezing
Solid to liquid is
Melting
Liquid to gas is
Evaporation
Gas to liquid
Condensation
Gas to solid
Desublimation
Solid to gas
Sublimation
The boiling and melting point of a substance refers to
The temperature at which is will change state (melting point being solid to liquid and boiling point being liquid to gas
The energy transferred to a substance when it changes state is called
Latent heat
The temperature of the substance does or does not change at the point where it changes state?
Does not
What is the internal energy of a substance
Is the combined energy of the kinetic and potential energy of the particles in the substance (or system)
What is potential energy
The potential energy The particles have due to their position. Bigger the distance between particles the greater potential energy they have.
What happens if a gas is given more energy?
When a gas is heated (provided with more energy) its molecules gain more kinetic energy and move faster. The molecules therefore collide with surfsces more frequently and with more force.
What is temperature
Temperature is a measure of how hot or cold something is
Increasing the temperature of any sealed gas container
Increases the pressure
Increasing the temp of any sealed gas container increases the pressure. Give two reasons why?
The average kinetic energy of the molecules increases as heat energy is transferred to
them.
• The average speed of the molecules increases as the kinetic energy increases.
This causes the molecules to hit the sides of the container more frequently and with more force, therefore greater pressure.
Equation for energy and latent heat and mass
Energy = mass x specific latent heat
Pressure x volume =
Constant
P1xv2
P2xv2
The bottle is filled with water and inside is a small packet of sauce which also has some air sealed in the packet. As the bottle is squeezed the sauce packet sinks. Why?
When you squeeze the bottle inward, you are reducing the volume of the bottle. This reduction in volume increases the pressure of all of the gas, including air in the sauce packet. The increased pressure of the air and therefore decreased volume will make it slightly more dense reducing its ‘buoyancy’ causing it to sink lower.
Describe the characteristics of gases
There are almost no forces of attraction between particles. The particles have more energy than in liquids and solids so are free to move in random directions. Have low densities
If the temperature changes, it depends on
The mass of the substance, what it’s made of and the energy input
Energy (E), mass (M) and specific latent heat (L)
Energy (J) = mass (kg) x specific latent heay (J/KG)
When a substance is melting or boiling, you’re still putting in energy and so
Increasing the internal energy, but the energy is used for breaking bonds between particles rather than raising the temperature
When a substance is condensing or freezing, bonds are _________ beterrn particles, which releases energy. This means?
FORMING. The internal energy decreases, but the temperature doesn’t go down until all the substance has turned to liquid or solid.
What is specific latent heat of a substance
The amount of energy needed to change 1kg of it from one state to another without changing its temperature
