H.Chemistry final Flashcards
Explains the behavior of particles in terms of their motions
Kinetic theory
Energy of motion
Kinetic energy
4 properties of gases:
1-negligible volume
2-move in rapid, constant straight-line motion
3-Collide elastically
4-far apart with no attractive or repulsive force
Collision in which no kinetic energy is lost.
Elastic collision
Measure of average kinetic energy
Temperature
The _____________ the temperature, the _____ moving particles.
Higher
Faster
Temperature at which the motion of the particles theoretically ceases.
Absolute zero
Simultaneous collisions of billions of molecules within an object
Pressure
Force is created by _____.
Collisions
Pressure=?
Force
________
Area
Empty space, no collisions
Vacuum
Air molecule collisions
Atmospheric pressure
Typical sea level pressure
ATM
Barometric reading
mm Hg
Forces within a compound that hold it together
Intramolecular forces
Forces between compounds that hold these compounds together.
Intermolecular forces
Which two phases are fluid?
Liquids and gases
Why are liquids more dense than gases?
Because they have attractive forces
Temperature that a solid turns into a liquid
Melting point
The stronger the intermolecular force the _______ the melting point
Higher
Temperature at which a solid melts at 1.00 ATM atmosphere(101.3kPa) of pressure.
Normal melting point
Process of a liquid changing to a gas or vapor
Vaporization
Liquid to gas below boiling point
Happens only on the surface
Evaporation
How many particles escape during evaporation to become a gas
Only particles moving fast enough
As high speed particles escape this lowers the average kinetic energy and therefore the temperature.
Cooling process
Increasing temperature will _______ vapor pressure
Increase
The temperature at which the vapor pressure of a liquid is equal to the external pressure on a liquid.
Boiling point
Temperature when the vapor pressure equals the atmospheric pressure 1 atm=101.3kPa.
Normal boiling point.
Temperature of liquid _____ gets above the boiling point
Never
Three properties of solids:
1- tightly packed
2-do not flow(they vibrate)
3-incompressible
State the 3 states of a substance from least dense to the most dense
Gas liquid solid
The atoms, ions, or molecules are arranged in a very orderly, repeating 3D arrangement of particles known as the crystal lattice
Crystal
2 or more different substances of the same element in the same physical state.
Allotropes
A solid in which the particles are randomly arranged
Amorphous
The process in which a solid changes to a gas without passing through the liquid state
Sublimation
Gas or vapor becomes a liquid
Condensation
Vapor to a solid
Deposition
Liquid to a solid
Freezing
Diagram that shows relationship between solid,liquid, and gas states for a substance in a closed container at different temperatures and pressure.
Phase diagram
Temperature and pressure where all three common states of matter coexist in equilibrium
Triple point
Above this temperature, the substance can only exist as a gas.
Critical point
The amount of a substance that contains the same number of particles, 6.2x10^23 particles.
Moles
Consists of one element
Atom
Consists of two or more nonmetal elements
Molecule
Consists of a metal and a nonmetal/ NH4+
Formula unit
Unit for molar mass
g/mol
Simplest whole number ratio of moles of the atoms in a substance.
Empirical formula
Some multiple of the empirical formula.
Molecular formula
Equation to convert an empirical formula to a molecular formula.
X= molar mass
____________
Empirical formula
Steps to find the empirical formula
- get mass
- get moles
- get whole numbers(divide by small, multiply by 2,3,4 if needed)
Compound that has a specific number of water molecules bound to its atoms.
Hydrate
The study of quantative relationships between amounts of reactants used and products formed by a chemical reaction.
Stoichiometry
Amount of product that can be formed in a reaction and how much excess reactant is left over
Limiting reactant
The percentage of a certain product actually produced in a chemical reaction.
+ equation
Percent yield= actual yield
————– x 100
Theoretical yield
Pressure conversions
1.0atm=760.0mmHg=101.3kPa=14.7psi=760.0torr
What happens to the temperature of a boiling liquid when heat is added to it?
Remains constant
What are four variables that effect gas behavior?
Pressure, volume, moles, and temperature
Relationship between pressure and volume, law name and equation
•Inversely proportional, as volume increases, pressure decreases
•Boyle’s law
•P V = P V
1 1 2 2
Relationship between pressure and temperature, law name and equation
• directly proportional
• gay-lussac's law
• P1 P2
--- = ----
T1 T2Relationship between pressure and moles, law name and equation
- Directly proportional
- Ideal gas law
- PV=nRT
Relationship between temperature and volume, law name, and equation.
•directly proportional •Charles' law • V1 V2 ---- = ---- T1 T2
Equation of combined gas law
P1V1= P2V2
—— ——-
T1 T2
What are the conditions of STP?
273.15k & 101.3kPa
Standard molar volume
22.4 L
Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.
Avogadro’s principle
A gas that follows the assumptions of the kinetic molecular theory
Ideal gas
What does the R in PV=nRT and PM=DRT represent?
Universal gas constant
When would a real gas become less ideal
In low temperature and high pressure
At constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the individual( partial ) pressure. + equation
Dalton’s law
P(total)=P1+P2+P3…
Dalton’s law correction equation
P(total)=P(gas)+P(water)
Tendency of molecules to move from an area of high concentration to low concentration until uniformly mixed.
Diffusion
Rate at which gases escape from a small hole in a container
Effusion
The rate of effusion of a gas is inversely
proportional to the square root of the gases molar mass.+equation.
Graham’s law
Rate A Molar mass B
——–=(square root) ———
Rate B Molar mass A
Homogenous mixture; solute+solvent
Solution
Present in greater amount
Solvent
Substance being dissolved
Solute
The process of surrounding solute particles to form a solution
Solvation
Describes liquids that are insoluble in each other
Immiscible
Two liquids that are soluble in any proportion
Miscible
Polar solutes dissolve in polar solvents, and Nonpolar solutes dissolve in Nonpolar solvents.
Like dissolves like
Why are ionic compounds electrolytes?
They conduct electricity
Three factor that affect the rate of solvation
- Agitation or Stirring
- increasing the surface area
- Heating
Maximum amount of solute that can be dissolved in a given amount solvent at a given temperature.
Solubility
Type of solution in which more solute can be dissolved.
Unsaturated
Type of solution in which no more solute can be dissolved at that temperature.
Saturated
More is dissolved than should be at that given temperature.
Supersaturated
How is solid solubility different from gas solubility as it relates to temperature?
Solid solubility usually increases with an increase in temperature and gas solubility usually decreases with and increase in temperature.
How is gas solubility related to pressure?
It’s directly proportional to pressure.
What is the colligative property?
A property that depends on the number of solute particles, not the nature of the particle.
How is vapor pressure affected when you increase the number or solute particles?
Decreases
How is the boiling point affected when you increase the number or solute particles?
Increases
How is the freezing point affected when you increase the number or solute particles?
Decreases
% mass equation
= mass of solute
—————– X 100
Mass of solute+ Mass of solvent
% volume equation
Volume of solute
——————- X 100
Volume of solution
% mass/ volume equation
Mass solute(g)
—————- X 100
Volume of solution(ml)
The amount of solute in a solution
Concentration
Molarity equation
M = moles of solute / Liters of solution
When diluting you use this equation:
M1V1=M2V2
Molality equation
m= moles of solute / mass of solvent(kg)
Visible scattering of light caused by the reflection off particles
Tyndall effect
- Mixture with particles so large, they settle out.
- Positive or negative Tyndall affect?
- type of mixture?
- Suspension
- positive
- heterogeneous
- Mixture with intermediate sized particles small enough that the moving water molecules keep them stirred up.
- type of mixture?
- do they settle out?
- positive or negative Tyndall effect?
- Colloid
- heterogeneous
- no, don’t settle out
- positive
- particles are uniformly mixed throughout.
- do they settle out?
- particle size?
- Tyndall effect?
- type of mixture?
- solution
- no,don’t settle out
- small particles
- negative Tyndall effect
- homogeneous
Mole fraction equation
Xa= na Xb= nb
——— ———
na+nb na+nb
Boiling point elevation equation
Tb= kb x m x i
Freezing point depression equation
Tf= kf x m x i
What are the three main parts of collision theory?
- reacting substances must collide
- reacting substances must collide with correct orientation.
- reacting substances must collide with sufficient kinetic energy to form the activated complex.
An unstable arrangement of atoms that forms for a moment at the peak of the activation-energy barrier.
Activated complex
Minimum energy needed for a successful reaction.
Activation energy
Increases reaction rate, lowers the energy of activation.
Catalyst
Decreases reaction rate, lowers the energy of activation.
Intermediate
4 factors that affect the reaction rate and how do they affect them?
- Temperature-increasing it usually increases reaction rate.
- Catalyst- increases reaction rate
- Concentration- more collision increases the reaction rate
- Particle size- decreasing particle size, increases surface area, and makes the reaction rate faster.
Average reaction rate equation
R= -[ change in reactant concentration ]
—————————————–
change in time
In order for a reaction system to be in equilibrium,
- The reaction must be reversible
- the forward and reverse rates must be equal
- the concentrations of the reactants and products must be constant, but not necessarily equal
- if a reaction shifts to the right, the forward rate is larger than the reverse rate.
At a given temperature, a chemical system may reach a state in which a particular ratio of reactant and product concentration is constant
Equilibrium constant expression
What does K(eq)>1 mean?
More products than reactants at equilibrium.
What does K(eq)<1 mean?
More reactants than products at equilibrium
If a system at equilibrium is stressed, the equilibrium will shift until the stress is relieved.
Le Chatelier’s principle
How does temperature affect equilibrium ?
If the reaction is endothermic it will shift to the right and if it’s exothermic, it will shift to the left.
How does pressure and volume affect equilibrium ?
Increasing the pressure/ decreasing volume favors the side with the fewer gas particles
Acid, hydrogen ion or proton that ionizes to make H+ protons.
Base, hydrogen ion or proton that ionizes to make OH-.
Arrhenius model Acid
Acid, proton or hydrogen-ion donor
Base, proton or hydrogen-ion acceptor
Bronsted-Lowry model
Difference between a strong and a weak acid/base?
Strong acids/bases completely ionize and weak acids/bases only partially ionize.
