Unit 4 - Lesson 4: Temperature & Pressure In Gases Flashcards
What is the coldest temperature in the universe?
Absolute zero.
Absolute zero is the temperature at which particles have no…what?
No kinetic energy.
Why do scientists believe nothing can actually reach absolute zero?
Because kinetic particle theory states all particles must always be moving. If particles at absolute zero have no kinetic energy, then this theory wouldn’t exist.
What is kinetic ‘particle’ theory?
Particles always move.
What is absolute zero in degrees Celsius?
-273.15 degrees Celsius, but we often round to -273 degrees Celsius.
What is absolute zero in kelvin?
0 K (kelvin)
What is the starting position for kelvin?
1 K starts at absolute zero.
How do you convert degrees Celsius into Kelvin?
Add 273 to the degrees Celsius.
How do you convert Kelvin into degrees Celsius?
Subtract 273 from Kelvin.
What does kinetic ‘particle’ theory show us about the connection between the temperature and energy of particles?
Kinetic ‘particle’ theory shows us that particles lose energy the colder they get. This means they move less and move closer together.
What is the coldest natural thing in the universe?
The Boomerang (also called bow tie) nebula is the coldest natural thing in the universe at -272.15 degrees Celsius.
What state is the kelvin scale amazing at describing?
Gases
What kinetic energy does 0 kelvin start at?
0 Kinetic energy
Why can we say the energy in kinetic energy stores and temperature are proportional?
The energy in kinetic energy stores decreases as temperature decreases and increases as temperature increases so we can say they’re proportional.
What is the temperature of a gas (in K) proportional to?
The average energy in the kinetic energy store of its particles.
What is pressure in gases the result of?
Colliding particles
At high pressures, do particles collide more or less?
At high pressures, particles collide more.
As particles collide with the side of the container, what do they exert on it?
A force. Pressure is force per unit area, for example: for per cm^3.
Explain why if more particles are colliding with the container, the pressure is higher.
If more particles are colliding with the container, they’ll be exerting more force per cm^3. So, the pressure is higher.
Complete the sentences:
As temperature increases, [?] energy increases.
As kinetic increases, [?] increases and therefore pressure increases.
For this reason, we can say [?] (in Kelvin), [?], and [?] are proportional.
We can even say the [?] of the container is [?] proportional.
As temperature increases, KINETIC energy increases.
As kinetic energy increases, COLLISIONS increases and therefore pressure increases (more particles are colliding with the container, so they’ll be exerting more force per cm^3, thus pressure is heightened).
For this reason, we can say TEMPERATURE (in Kelvin), KINETIC ENERGY, and PRESSURE are proportional.
We can even say the VOLUME of the container is INVERSELY proportional (meaning, as the others go up, the volume goes down).
The pressure x volume for ideal gases in a container at the start will equal the pressure x volume at the end, even if the pressure of gas or volume of container changes. How do we write this as a formula?
P1V1 = P2V2
(Note: the numbers are in subscript)
The pressure x volume for ideal gases in a container at the start will equal the pressure x volume at the end, even if the pressure of gas or volume of container changes. Because pressure, temperature, and kinetic energy are proportional, what must we keep the same (constant) for this to work?
The temperature.
Example Question:
A canister of volume 200cm^3 contains a gas at a pressure of 150 kPa. The canister is then compressed to a volume of 100cm^3. The temperature never changes. What is the pressure of the gas now?
150 x 200 = P2 x 100
30,000 = P2 x 100
30,000 / 100 = P2
P2 = 300 kPa
The pressure / temperature (Kelvin) at the start will equal pressure / temperature (K) at the end, even if one of the variables change. How can we write this as a formula?
P1/T1 = P2/T2
