Transcript STAAR Ladder to Success - Grandview Independent School

STAAR Ladder to Success
Rung 4
Boyle’s Law
• The pressure and volume of a gas
are inversely related
– at constant mass & temp
P1V1 = P2V2
Charles’ Law
• The volume and absolute
temperature (K) of a gas are
directly related
– at constant mass & pressure
V1T2 = V2T1
Dalton’s Law
• The total pressure of a mixture of
gases equals the sum of the
partial pressures of the individual
gases.
Ptotal = P1 + P2 + ...
Avogadro’s Principle
• Equal volumes of gases contain
equal numbers of moles
– at constant temp & pressure
– true for any gas
1 mol = 22.4 L
Ideal Gas Law
PV=nRT
You don’t need to memorize these values!
STP
STP
Standard Temperature & Pressure
0°C
273 K
-OR-
1 atm
101.325 kPa
Example #1
• The pressure on a balloon with a volume of
300 mL increases from 1.10 to 2.00 atm.
Calculate the new volume of the balloon.
Example #2
• The air in a balloon with a volume of 25 L is
heated from 20 C to 60 C. If the pressure
stays the same, what will be the new volume
of the balloon?
Example #3
• A sample of gas in a 1L flask at 1.5 atm
contains 75% CO2 and 25% H2O gas. Calculate
the partial pressures of each gas.
Example #4
• Calculate the temperaure of 5.85 mol N2 gas in
a 12 L steel bottle under 10 atm of pressure.
Gas Stoichiometry
• Moles  Liters of a Gas:
– STP - use 22.4 L/mol
– Non-STP - use ideal gas law
• Non-STP
– Given liters of gas?
• start with ideal gas law
– Looking for liters of gas?
• start with stoichiometry conv.
Example #1
• What is the mass of oxygen gas produced
when 29.2 g of water is decomposed by
electrolysis according to the balanced
equation?
2H2O  2H2 + O2
Example #2
• What volume in L of nitrogen dioxide gas is
produced when 34 L of oxygen gas react with
an excess of nitrogen monoxide? Assume
conditions of STP.
2NO + O2  2NO2
Kinetic Molecular Theory
• Gases are made of molecules in constant,
random motion
• The volume is small
• Collisions are elastic
• Forces (attractive and repulsive) are small
• Average kinetic energy is proportional to
temperature