Test 4 – Chemistry Test Answers

Flashcard maker : Steven Colyer
What uniformly fill any container, are easily compressed, and mix completely with like substances?
Earth’s atmosphere is about what percent of nitrogen?
Earth’s atmosphere is about what percentage of oxygen gas?
The universes about what percent of hydrogen gas?
What results from the weight of the air (mass of air is being pulled toward the center of earth by gravity)?
atmospheric pressure
Who invented the barometer in 1643?
Evangelista Torricelli
device used to measure atmospheric pressure
What corresponds to bad weather?
low atmospheric pressure
What is atmospheric pressure at sea level?
What is the atmospheric pressure in higher elevations (such as Breckenridge, Colorado)?
520mmHg (thin air)
what is measured in Newtons?
What is is measured in square meters?
What is one N/m^2?
What is the Pascal the SI unit for?
unit for pressure
How many Pascals are in one atmosphere?
How many inches of Hg are in one atm?
How many pounds per square inch are in one atm?
What is Boyle’s Law?
What are gases that obey the gas laws termed?
ideal gases
What make gases deviate from ideal gas behavior?
high pressure and low temperature (makes them closer together)
Who was the first to fill a balloon with hydrogen gas and first to make a solo balloon flight?
Jacques Charles
What is Charles’ Law?
The volumes of all gases extrapolate to what?
0K or -273.15C
What is Avogadro’s Law?
What is the ideal gas law?
Pressure units
volume units
temp units
What is the molar volume of one mole of a gas at STP?
What is the molar mass formula?
for a mixture of gases in a container, the total pressure exerted is the sum of the pressures that each gas in a mixture of gases in a container depends on the number of moles of that gas
Dalton’s Law of Partial Pressure
What is made from sodium azide?
balance the decomposition of sodium azide
What do laws do?
summarize observed behavior
What do theories do?
explain why
When are models considered successful?
if i explains the observed behavior in question and predicts correctly the result of future experiments
Why is the volume of an individual particle assumed to be zero?
particles are so small compared with distances between them
What are the causes of pressure exerted by the gas?
particles are in constant motion so collisions of the particles with walls are the causes
particles are assumed to exert nor forces on each other
they are assumed neither to attract nor repel each other
What is assumed to be directly proportional to the Kelvin temp of the gas (ideal not real)
average kinetic energy of a collection of gas particles
What is the root mean square velocity formula?
square root of 3RT/M
What are the units for root mean square velocity?
What is the value for R in the root mean square velocity formula?
8.3145 J/molK
What is the si unit for energy
What is the average distance a particle travels between collisions in a particular gas sample
mean free path
What is the ration of the number of moles of a given component in a mixture both total number of moles in the mixture?
mole fraction
mixing of gases
passage of a gash through a tiny orifice into a vacuum
rate of the mixing of gases
rate of diffusion
measure the speed at which the gas is transferred into the chamber
rate of effusion
What is the formula for Graham’s law of effusion?
Rate of effusion for gas 1/rate of effusion for gas 2
square root of M2/ square root of M1
Who developed an equation for real gases?
Johannes van der Waals
layer of atmosphere closest to earth with all clouds and weather
What are the two main sources of pollution?
transportation and production of electricity
Would gases act more ideally with a few moles involved or a great number of moles involved?
few, gases don’t like to be close together
One mole of gas contains how many molecules?
One mole of any gas occupies how many liters at STP?
Diatomic molecules exhibit what kind of bonding? (share electrons equally)
non polar covalent
Which of the following gases diffuse faster? Oxygen gas or Butane gas? Why?
Oxygen, mass of oxygen is less than mass of butane
average kinetic energy
If all the gases have the same temperature, what happens?
they all have the same kinetic energy
If volume increases on a gas, what happens to pressure?
decreases (Boyle’s Law)
Gases act most ideally under what conditions?
high temperature and low pressure
What factor is used to determine if gases have the same partial pressures?
Would a gas exert greater pressure as an ideal gas or as a real gas?
ideal gas (postulates)

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