# Shared Flashcard Set

## Details

Atmosphere Section A
Atmosphere structure, gas pressure and gas laws
30
Chemistry
05/25/2011

Term
 The 4 properties of a gas that can be measured are
Definition
 volume, pressure, temperature and number of particles (or moles)
Term
 How do you convert a Celsius temperature to a Kelvin temperature?
Definition
 Add 273 to the Celsius temperature.
Term
 What is room temperature in Celsius?
Definition
 Approximately 25 °C.
Term
 Convert -50 °C to Kelvin.
Definition
 -50 + 273 = 223 K
Term
 These two gases make up most of the troposphere (lowest level of the atmosphere)
Definition
 N2 and O2
Term
 The 3 levels of the atomsphere are called the ____________, ______________ and ______________.
Definition
 Troposphere, Stratosphere, and Mesosphere
Term
 The levels of the atmosphere are defined by looking at changes in which property of the atmosphere?
Definition
 The temperature.  It drops as you rise into the troposphere, then it rises again through the stratosphere, and finally it drops as you enter the mesosphere.
Term
 As altitude increases, air pressure   (rises / drops / stays the same / fluctuates)
Definition
 drops
Term
 What causes a temperature increase in the stratosphere?
Definition
 Ozone molecules.  O3
Term
 The device that measures air pressure is called a ____________ and it is filled with this liquid.
Definition
 barometer; filled with mercury (Hg).
Term
 As you increase altitude, the air gets "thinner".  If air is "thinner" there are (more / fewer) molecules.
Definition
 fewer.
Term
 Which creates a higher pressure on a desk surface - a book resting on its spine or a book lying flat, and why?
Definition
 The book on its spine.  Both situations have the same force acting on the desk (the weight of the book) but when the book is one its spine the force is acting over a smaller area, so the pressure is higher.   Pressure = force/area.
Term
 This scientist studied the relationship between gas volumes and temperatures.
Definition
 Charles.
Term
 This scientist studied the relationship between gas volumes and pressures.
Definition
 Boyle.
Term
 This scientist studied the relationship between gas pressures and temperatures.
Definition
 Gay-Lussac
Term
 The relationship between a gas' volume and its temperature is (direct / inverse).
Definition
 direct
Term
 An inverse relationship exists between a gas' pressure and its (temperature / volume).
Definition
 Volume.
Term
 STP stands for
Definition
 Standard temperature and pressure.   0 °C and 1 atm    This doesn't mean "normal" temperature and pressure.    It just is a temperature and pressure that scientists use to report gas volumes at.
Term
 The equation for Gay-Lussac's law is
Definition
 P1/T1  =  P2/T2   Remember that temperature must be in Kelvin!
Term
 The equation for Charles' Law is
Definition
 V1/T1  =  V2/T2   Remember that temperature must be in Kelvin!
Term
 The equation for Boyle's Law is
Definition
 P1V1=  P2V2
Term
 At STP, the volume occupied by one mole of any gas is
Definition
 22.4 Liters.
Term
 In the reaction __ N2 + ___ H2 → ___ NH3, how many liters of ammonia are produced from 6 liters of H2?
Definition
 4 liters NH3.
Term
 In the reaction __ N2 + ___ H2 → ___ NH3, how many moles of ammonia are produced from 84 grams of N2?
Definition
 6 moles NH3.
Term
 A gas occupies a volume of 15 mL at 300 K.  If the temperature rises to 500 K, what is the new volume of the gas?
Definition
 25 mL
Term
 A gas at a temperature of 250 K exerts a pressure of 1.5 atm in a rigid box.  If the temperature drops to 150 K, what is the new pressure of the gas?
Definition
 0.9 atm.
Term
 If the volume of a gas sample is 2 Liters when the pressure is normal atmospheric pressure, what will the new volume be if the pressure drops to 0.4 atm?
Definition
 5 Liters.
Term
 In the reaction __ H2 + ___ O2 → ___ H2O, how many liters of water vapor are produced from 4 liters of O2?
Definition
 8 Liters.
Term
 If all the reactants and products are gases in a chemical reaction, then the coefficients of a balanced equation can be interpreted as moles or ________.
Definition
 Liters (or any volume unit).
Term
 Imagine a gas sample in a rigid, fixed-volume container.  If that container is heated, the gas sample will rise in temperature and its density will (increase / decrease / not change).
Definition
 not change!  Density is mass/volume.  By heating the gas, its pressure will rise, but you are not affecting the mass of the sample nor the volume it occupies, since it is in a rigid (fixed-volume) container.
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