second semester chem PART TWO
split it up to make it easier to study
Terms in this set (100)
why does the pressure inside a container of gas increase if more gas is added to the container?
there is an increase in the number of collisions between particles and the walls of the container
how does the gas propellant move when an aerosol can is used?
from the region of high pressure to a region of lower pressure
if the volume of a container of gas is redcued what will happen to the presssure inside the container?
the pressure will increase
if a balloon is squeezed what happens to the pressure of the gas inside the balloon?
as the temperature of the gass in a balloon decreases what occurs?
the average kinetic energy of the gas decreases
what happens to the pressure of a gas inside a container if the temperature of the gas decreases?
the pressure decreases
what does air escape from a tire when the tire valve is opened?
the pressure outside the tire is lower then the pressure inside the tire
what does NOT cause an increase in the pressure of a contained gas?
the volume of the container is increased
when the kelvin temp of an enclosed gas doubles, the particles of the gas ___.
the volume of a gas is doubled while the temp is held constant. how does teh gas pressure change?
it is reduced by one half
the volume of a gas is reduced from 4L to 0.5 L while the temperature is held constant. how does the gas pressure change?
it increases by a factor of four
if a balloon is heated what happens to the volume of the air in the balloon if the pressure is constant?
when the pressure and number of particles of a gas are constant, which of the following is also constant?
the ratio of the volume and temp in kelvins
if a ballooon is heated, what happens to the pressure of the air inside the balloon if the volume remains constant?
when teh volume and number of partciles of a gas are constant, what is also constant?
the ratio of pressure and temp in kelvin
if a seal syringe is plunged into cold water, in which direction will the syringe piston slide?
what happens when a piston is used to decrease the voulme of a contained gas?
gas particles become compressed
if a seal syringe is heated, in which direction will the syringe plunger move?
the combined gas law relates what?
temperature, pressure and volume
what does the ideal gas law allow a scientist to calculate that the other gas laws do not?
number of moles
at a certain temp and pressure, 0.20 mol of carbon dioxide has a volume of 3.1 L. A 3.1 Liter sample of hydrogen at the same temp and pressure ___
contains the same number of molecules
how is the ideal gas law usually written?
which law can be used to calculate the number of moles of a contained gas?
ideal gas law
what is the constant for 1 mole of any ideal gas? (forumla)
PV / T
at high pressure, how does the volume fo a real gas compare with the volume of an ideal gas under the same conditions?
it is much greateer
at low temperature and presssure, who does the volume of a real gas compare with the colume of an ideal gas under the same conditions?
it is less
an ideal gas CANNOT be?
under what conditions of temp and pressure is the behavior of real gases most like that of ideal gases?
low temp and high pressure
if the atmospheric pressure on Mt. everest is one-third the atmospheric pressure at sea level, the partial pressure of oxygen on Everest is ___
on third its pressure at sea level
what happens to the partial pressure of oxygen in sample of air if the temp is increased?
what happens to the partial pressure of oxygen in a sample of air if the temp is increased?
if oxygen is removed from a sample of air as iron rusts, what happens to the total pressure of the air?
if the volume of a container of air is reduced by one-half, what happesn to the partial pressure of oxygen within the container?
it is doubled
which of the following atoms would have the greatest velocity if each atom had the same kinetic energy?
whih gas is the best choice for inflating a ballooon that must remain inflated for a long period of time?
what usually makes a substance dissolve faster in a solvent?
agitating the solution
what is the maximum amount of KCl that can dissolve in 200 g of water? ( solubility of KCl is 34g / 100g H₂O at 20°C)
what is the solubility of silver nitrate if only 11.1 g can dissolve in 5.0 g of water at 20°C?
222g/100g H₂O at 20°C
what factors affect the solubility of a particular substance?
temp and the nature of solute and solvent
what substance is less soluble in hot water than in cold water?
What occurs as the temp increases? ( in terms of solvents, solubility, etc)
the solubility of a gas in a liquid is___
directly proportional to the pressure of the gas above the liquid
if the solubility of a particular solute is 10g/100g H₂O at 20°C, what is the solution concentration that would represent a supersaturated aqeuous solution of that solute?
11g/100g H₂O at 20°C
what happens to the solubility of a gas, in a liquid, if the partial pressure of the gas above the liquid decreases?
the solubility decreases
in a concentrated solution there is ___
a large amount of solute
what is the molarity of a solution that contains 6 moles of solute in 2 liters of solution?
The solution for molarity:
10 mol of solute/1 L of solution
what is the molarit of 200 mL of solution in which 2.0 moles of sodium bromide is dissolved?
what is the number of moles of solute in 250 mL of a 0.4M solution?
what mass of sucrose, C₁₂H₂₂O₁₁, is need to make 500.0 mL of a 0.200M solution?
what mass of Na₂SO₄ is needed to make 2.5 L of 2.0M solution? (Na=23g ; S=32g ; O=16g)
what does NOT change when a solution is diluted by the addition of solvent?
number of moles of solute
if 2.0 mL of 6.0 M HCl is used to make a 500.0 mL aqueous solution, what is the molarity of the dilute solution?
To 225 mL of a 0.80M solution of KI, a student adds enough water to make 1.0 L of a more dilute KI solution. What is the molarity of the new solution?
if the percent by volume is 2.0% and the volume of solution is 250mL, what is the volume of solute in solution?
How is concentration expressed in percent by volume?
if the percent (mass/mass) for a solute is 4% and the mass of the solution is 200 g, what is teh mass of solute in solution?
how many millilters of alcohol are in 167 mL of an 85.0% (v/v) alcohol solution?
which concentration is expressed in percent by volume?
10mL of solute/100mL of solution X 100%
what is NOT a colligative property of a solution?
what is molality?
10 mol of solute/1kg of solvent
what is the mole fraction of ethanol in a solution of 3.00 moles of ethanol and 5.00 moles of water?
what is the molality of a solution containing 8.0 grams of solute in a 0.50 kg solvent? (molar mass of solute= 24 g)
what is the number of kilograms of solvent in a 0.70 molality solution containing 5.0 grams of solute? (molar mass of solute = 30g)
to which of the following variables is change in boiling point directly proportional?
molality of solution
what is the freezing point of a solution of 0.5 mol of LiBr in 500 mL of water (Kf = 1.86°C/m)
what is the boiling point of a solution of 0.1 mole of glucose in 200 mL of water? (Kb = 0.512°C/m)
what is the approximate molar mass of a molecular solute if 300 g of the solute in 1000 g of water causes the solution to have a boiling point of 101°C ( Kb= 0.512°C/m ; Kf=1.86°C/m ; molar mass of water = 18g)
what happens to the energy produced by burning gasoline in a car engine?
the energy is lost as heat in the exhaust, transformed into work to move the war heats the parts of the engine
a piece of metal is heated, then submerged in cool water. describe what happens.
the temp of the water will increase and the temp of the metal will decrease
how does a calorie compare to a joule?
a calorie is larger than a joule
what would likely happen if you were to tough the flask in which an endothermic reaction were occurring?
the flask would probably feel cooler then before the reaction started
when energy is changed from one form to another,___.
all of the energy can be accounted for
in an exothermic reaction, the energy stored in the chemical bonds of the reactants is___
greater than the energy stored in the bonds of the products
when your body breaks down sugar completely, how much heat is released compared to burning the same amount of sugar in a flame?
the body releases the same amount of heat
a pieced of candy has 5 Calories ( or 5000 calories). if it could be burned, leaving nothing but carbon dioxide and water, how much heat would it give off?
how many joules are in 148 calories? (1 cal=4.18 J)
the amount of heat transferred from an object depends on what?
the specific heat, the initial temperature, and the mass of the object
what does the symbol ΔH stand for?
the heat of reaction for a chemical reaction
how can the enthalpy change be determined for a reaction in an aqueous solution?
by mixing the reactants in a calorimeter and measuring the temp change
a chunk of ice whose temp is -20°C is added to an insulated cup filled with water at 0°C. What happens in the cup?
some of the water freezes, so the chunk of ice gets larger
calculate ΔH for the following reaction: C₂H₄ + H₂→C₂H₆ (ΔH for C₂H₄ = 52.5 kJ/mol ; ΔH for C₂H₆ = -84.7 kJ/mol)
calculate the energy released when 24.8 g Na₂O reacts in the reaction: Na₂O +2HI→ 2NaI + H₂O (ΔH = -120.00 kcal)
the ΔH(soln) is ___.
sometimes positive, sometimes negative
when 1.0 g of solid NaOH (ΔH(soln) = -445.1 kJ/mol_ dissolves in 10 L of water, how much heat is release?
when 10 g of diethyl ether is converted to vapor at its boiling point, how how much heat is absorbed? (C₄H₁₀O; ΔH= 15.7 kJ/mol ; boiling point: 34.6°C)
what is Hess's law?
makes it possible to calculate ΔH for complicated chemical reactions
what is the change in enthalpy equal to?
ΔH of products minus ΔH of reactants
ΔH for the formation of rust (Fe₂O₃) is -826 kJ/mol. How much energy is involved in the formation of 5 grams of rust?
Calculate ΔH for the reaction of sulfur dioxide with oxygen. 2SO₂ + O₂→2SO₃
(ΔH SO₂ = -296.8 kJ/mol ; ΔH SO₃ = -395.7 kJ/mol )
what is the amount of heat required to raise the temp of 200.0 g of aluminum by 10°C? ( specific heat of alumnium = 0.21 cal/g°C)
what is the specific heat of a substance if 1560 cal are required to raise the temp of a 312 g samp;e by 15°C?
how many kiolcalories of heat are required to raise the temp of 225 g of aluminum from 20°C to 100°C? (specific heat of alumnium = 0.21 cal/g°C)
the heat capacity of an object depends in part on its ___.
what is the valid unit for specific heat?
when 45 g of an alloy, at 25°C, are dropped into 100.0 g of water, the alloy absorbs 956 J of heat. If the final temp of the alloy is 37°C, what is its specific heat?
how can you describe the specific heat of olive oil if it takes approx 420 J of heat to raise the temp of 7 g of olive oil by 30°C?
less then the specific heat of water
the specific heat of silver is 0.24 J/g°C. how man joules of energy are needed to warm 4.37 g of silver from 25.0°C to 27.6°C?
which of the following has the greatest heat capacity? a) 1000 g of water b) 1000g of steel c) 1 g of water d) 1 g of steel
1000 g of water
what substance has the highest specific heat?