Studied by 1 person
Looks like no one added any tags here yet for you.
What is the formula/definition for the relative atomic mass?
Average mass of one atom of an element*12/mass of one atom of 12C
What is the formula/definition of the relative molecular mass?
Average mass of one molecule*12/mass of one atom of 12C
What is Avogadro's constant?
it is 6.02*10^23
What is the formula for mass?
Mass= Mr * Mol
What is the formula for solutions
Moles= Conc * Vol
What is the formula for particles?
No of particles = Avogadros number * Mole
What is the formula for original concentration?
new concentration * dilution factor
What is the volume for 1 mole of any gas?
22.4dm^3
What is the formula for the ideal gas equation?
pV=nRT
p= pressure
V= volume
n= number of moles
R= constant (8.31)
T= Temperature
How to convert from dm^3 to m^3
/1000
m^3 to cm^3
*1,000,000
dm^3 to cm^3
*1000
how to convert from kelvin to celsius and vice versa
-273
+273 for celsius to kelvin
how to convert from kPa to Pa
*1000
what is 1.00 atm pressure?
101000 Pa
How to get from molecular to empirical formula?
You divide by the smallest whole number.
What is the formula to get molecular formula?
Mr/Empirical mass
What does metal + acid make?
Salt + hydrogen
What does metal oxide + acid make?
Salt + water
What does metal hydroxide + acid make?
Salt + water
What does metal carbonate + acid make?
Salt + water + carbon dioxide
What do combustion reactions always produce?
Oxides
When fuels are burnt what do they make?
They make CO2 and H2O if it's complete combustion
If it's incomplete then it will make CO and CO2
What are the 7 diatomic elements?
Hydrogen
Nitrogen
Fluorine
Oxygen
Iodine
Chlorine
Bromine
What will a more reactive element displace?
A less reactive element
What elements are in the reactivity series?
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum
What are the solubility rules?
""
Formula for percentage purity
actual mass of the substance/ mass of impure substance X100
Formula for percentage yield
Actual yield/ Theoretical yield X100
Formula for atom economy
molar mass of desired product/ total molar mass (Mr) of all products/reactants X100
What is the definition of enthalpy change?
The heat change under a constant pressure
What happens in an exothermic reaction?
Heat is given out so temperature of surroundings increase
What happens in an endothermic reaction?
The heat is taken in so the temperature of the surroundings decreases
What are the standard condition?
100kpa - pressure
298K - temperature
1 mol dm-3 - concentration (only if solutions are present)
Defintion of the enthalpy change of reaction?
The enthalpy change for a reaction with the quantities shown in the chemical equation. This means the value should always be quoted along with the equation
Definition of the enthalpy change of formation?
When 1 mole of substance is formed from its constituent elements with all reactants and products in standard states under standard conditions
Definition of enthalpy change of combustion?
"Enthalpy change when 1 mole of a substance is completely burned in oxygen with all reactants and products in standard states under standard condition"
Definition of enthalpy change of neutralisation?
"Enthalpy change when 1 mole of water is formed in a reaction between the acid and alkali under standard conditions"
What does it mean when it says standard states?
The molecule at room temperature
Symbol for enthalpy change
""
Symbol used to show that the experiment was carried out in standard conditions
""
What is the standard enthalpy symbol for formation?
""
What is the standard enthalpy symbol for combustion?
""
What is the standard enthalpy symbol for reaction?
""
What is the standard enthalpy symbol for neutralisation?
""
What is the equation to find out heat gained/lost?
q = m c delta T
What is the density of water with 1g
1g = 1cm^3
How to calculate enthalpy change of combustion?
heat loss/gain / moles
What is Hess's law?
The total enthalpy change of a reaction is independent of the reaction route
Why is direct measurement not possible?
The reaction is incomplete
Side reactions occur
The reaction is too slow
When using combustion data, which ways do the arrows point?
They point downwards
What do you do when you go against the arrow?
You reverse the sign e.g if the normal sign is - and the arrow goes the other way, the sign is +
What direction do the arrows go in formation data?
They go up
What is the definition of enthalpy of solution?
The enthalpy change associated with the dissolution of a substance in a solvent at constant pressure resulting to infinite dilution
What is the definition of the lattice enthalpy of dissociation?
Enthalpy change needed to convert 1 mole of solid crystal into its scattered gaseous atoms
What is the definition of the enthalpy of hydration?
The enthalpy change when 1 mole of gaseous ions dissolve in sufficient water to give an infinitely dilute solution
What influences the value of enthalpy of hydration?
size and charge
How does size and charge influence the value of enthalpy of hydration?
Size: Smaller ion with the same charge e.g Li+ compared to Na+ will have a larger charge density
Charge: 2+ have a larger charge density than 1+ ions so there is a stronger attraction from the 2+ than from the 1+
What is are the conditions needed for particles to collide successfully?
Particles have to collide facing in the right orientation
Must have sufficient kinetic energy - Activation energy
What is the transition state?
Point of the highest energy
Definition of asymptote?
The theory that particles have no limit in energy so the line never touches the x - axis
What is the definition for the most probable energy?
The peak where the most number of particles are
How does reducing the volume affect the Maxwell - Boltzmann graph?
NO DIFFERENCE
How does adding an inert gas affect the Maxwell - Boltzmann graph?
NO DIFFERENCE
How does reducing the temperature affect the Maxwell - Boltzmann graph?
""
What is the definition for dynamic equilibrium?
"The forward and backward reactions happen at the same rate and the concentrations are the same"
What is Le Chatelier's Principle?
If a reaction at equilibrium is subjected to a change in concentration, pressure or temperature, the position of equilibrium will move to counteract the change
What does increasing the temperature do to the reaction?
It will shift the equilibrium to the endothermic direction to absorb the heat. This means if the forward reaction is exothermic, the equilibrium will move to the left side which will decrease the yield of product
What does decreasing the temperature do?
It will shift the equilibrium to the exothermic direction. This means if the reaction is exothermic and the temperature is decreased, the equilibrium will shift to the right side which will increase the product
What does increasing the conc of the reactant do?
Equilibrium will shift to the right so more product is made
What does increasing the product do?
It will shift the equilibrium to the left so more reactant is made
What does increasing the pressure do?
It will make equilibrium shift to the side with the least moles
What does decreasing the pressure do?
It will make equilibrium shift to the side with the most moles
How will you see if a reaction is exo or endo if it doesnt say in the question?
If delta H is - = exo
If delta H is + = endo
Conditions required to make methanol?
Requires a catalyst: mixture of copper, zinc and aluminium oxide
Decreased temperature
Higher pressure
This ensures a high yield and a fast ROR which will compromise each other
Conditions to make ethanol? (4)
Requires a catalyst: phosphoric acid catalyst absorbed on silica pellets
Decreased temperature, high yield but low ROR so compromise of 300 degrees
Higher pressure
All about compromise
What is the Kc ?
Ratio of the reactants:products in a mixture
What factors affect the Kc ?
Only applies at a particular temperature as if they increase/decrease, they would alter the value of Kc , this would decrease yield of product
What is the equation of Kc?
aA + bB = dD+eE
What is the actual formula?
""
What are the units for the Kc ?
mol dm-3
What is the oxidation state of an uncombined element?
0
What is the sum of the oxidation states of all the atoms or ions in a neutral compound?
0
Give an example of sum of the oxidation states of all the atoms or ions in a neutral compound
NaCl
What is the sum of the oxidation states of all the atoms in a simple monoatomic ion?
It would be equal to the charge on the ion
Give an example of what the sum of the oxidation states of all the atoms is in a simple monoatomic ion
K+ = +1
What is the overall oxidation state in compound ions equal to?
the overall ion charge
Give an example of what the overall oxidation state of compound ions is in NO3- .
N = +5 O = -2*3 = -6
Overall oxidation state of NO3- = -1
What is the overall oxidation state for elements existing as molecules with identical atoms?
0
Give an example of elements existing as molecules with identical atoms having an overall oxidation state of 0.
O2 Cl2
What is the electronegative rule?
The more electronegative element in a substance is given a negative oxidation state while the less electronegative element is given a positive oxidation state
What is the order of the electronegative elements?
Fluorine
Oxygen
Nitrogen
Carbon
Oxidation state in group 1?
+1
Oxidation state in Group 2?
+2
Oxidation state of Al?
+3
Note
Flashcard