Section 7 - Matter Flashcards
What is density?
How much space a substance takes up compared to its mass.
What is the equation for density?
ρ=m/V
ρ = Density m = Mass V = Volume
What makes an object float?
If its average density is less than the fluid’s density it will float. This is because the object is pushed above the fluid because the object’s weight will have displaced in a smaller area, preventing it from sinking.
How can a liquid’s density be worked out?
By measuring a set volumes mass and using the density calculation.
How can a solid’s density be worked out?
By measuring its mass, and how much liquid is displaced in a displacement can as its volume, density can be worked out using the density formula.
What is kinetic theory? How does it describe particle?
A method of explaining particles, where the particles making up matter are tiny balls with lots of forces between them. The way matter behaves can be explained with how the balls move and the forces between them.
What are the three states of matter?
Solid, liquid and gas.
How are the particles in a solid described, according to kinetic theory?
Close together in fixed regular arrangements due to strong forces of attraction, the particles don’t have much kinetic energy so they can only vibrate around fixed positions.
How are the particles in a liquid described, according to kinetic theory?
Close together in irregular arrangements due to weaker forces of attraction, the particles have some kinetic energy so they can move over one another easily in random directions at low speeds.
How are the particles in a gas described, according to kinetic theory?
Randomly, there are almost no forces of attraction between particles so they move at high speeds in random directions.
What is it called when a solid becomes a liquid?
Melting.
What is it called when a liquid becomes a solid?
Freezing.
What is it called when a liquid becomes a gas?
Evaporating.
What is it called when a gas becomes a liquid?
Condensing.
What is it called when either a solid becomes a gas or a gas becomes a solid?
Subliming.
How does density normally change with state.
Solids are more dense than liquids and liquids are more dense than gasses.
What is specific heat capacity?
The energy required to raise the temperature of 1kg of a substance by 1°C
What is specific latent heat?
The energy required to change the state of 1kg of a substance without changing its temperature.
What is the formula for specific heat capacity?
ΔQ=m×c×Δθ ΔQ = Change in Thermal Energy m = Mass c = Specific Heat Capacity Δθ = Temperature Change
What is the formula for specific latent heat?
Q=m×L
Q = Thermal Energy
m = Mass
L = Specific Latent Heat
How is gas pressure explained by kinetic theory?
Particles in a gas take up very little space, most of a gas is empty space. And because gas particles move about randomly at very high speeds they often collide with one another and whatever else is in the way, upon colliding with something they exert a force. In a sealed container, the outwards gas pressure is the total net force exerted by all of the particles in a gas per unit area of the container walls.
How does temperature affect gas pressure and why?
The speed of the particles in a gas depends on the temperature of the gas, so in higher temperatures, the particles move quicker than in the same gas at a lower temperature. Because the particles are moving at higher speeds, they collide with things more, exerting force more often. Additionally, the force exerted in each collision also increases at higher temperatures. This means the net force on the container walls also increases, meaning that the pressure increases with higher temperatures.
How does volume affect gas pressure and why?
Increasing a gas’s volume means the particles are more spread out, so they must travel further before colliding with either another particle or the container walls, so they collide less often. With fewer collisions, the net force acting on the container walls decreases and so the pressure decreases in larger volumes.
How is the relationship between gas volume and pressure in a sealed container displayed? What does this mean?
P₁V₁=P₂V₂ P₁ = Pressure 1 V₁ = Volume 1 P₂ = Pressure 2 V₂ = Volume 2 This means that pressure and volume are inversely proportional, so when volume increases, pressure must decrease.
