Unit 2, Week 1 Recap

Unit 2, Week 1 Recap

Pressure Unit Conversions, The Mole Concept, & Mole Conversions

Variables to Measure Gas Particles

• Pressure (P): Collisions between particles and container walls; measured in atm, mmHg, torr, psi, etc.

• Volume (V): 3D space for particles to move; measured in L, mL, cm³, dm³, etc.

• Number of Particles (n): measured in moles

• Temperature (T): Average kinetic energy of particles; proportional to Kelvin temperature ONLY!

Multiple Choice

How does gas pressure arise?

• 3D space for particles to move

• Number of moles of a gas

• Average kinetic energy of gas particles

• Particle collisions with walls of container

Multiple Choice

What the physical meaning of temperature of gas particles?

• Average kinetic energy of particles

• Average velocities of particles

• Average number of particle collisions with walls of container

• Average celsius temperature of particles

Moles & Mole Conversions

• 1 mole = 6.02 x 10²³ particles = "Avogadro's Number"

• Used to count huge numbers of tiny particles

• Molar Mass found on P.T. means 1 mole of that element has that mass in grams

• Molar Mass Unit: g/mol (#g = 1 mol)

Multiple Choice

What are the units for molar mass?

• grams
• amu
• grams/mole
• liters

Multiple Choice

How many hairs are in one mole of dog hair?

• Same as the mass

• 6.02 x 10^3

• Avogadro's number

• Undetermined

Multiple Choice

If a person has 80g of calcium, how many moles are present?

• 1

• 2

• 3

• Undefined.

Multiple Choice

How many grams are in 1.2 moles of neon?

• 0.059 grams

• 7.2 x 10²³ grams

• 2.0 x 10^-24 grams

• 24 grams

Variable Relationships

• P & V = INVERSE: less 3D space means particles collide with walls more often

• P & T = DIRECT: faster particles means more particle collisions with walls

• P & n = DIRECT: more particles means more particle collisions with walls of container

• T & V = DIRECT: higher velocity means particles push out walls to maintain constant pressure

Multiple Choice

If a hairspray can is heated, what can be expected of the pressure of the gas inside the can?

• The pressure will increase

• The pressure will decrease

• The pressure will remain constant

• The pressure will equalize

Multiple Choice

Which container will have lower pressure?

• left
• right
• they both have the same pressure

Multiple Choice

If a balloon is cooled what will happen to the volume?

• Volume will increase
• Volume will decrease
• Volume will not change