Amount Of Substance Flashcards
What is the ideal Gas equation?
Pv = n R T
What do the letter stand for in the Ideal Gas equation and what units are these measured in ?
P= pressure (pascals) V= volume (m cubed)
N= number of miles R= gas constant - 8.31 joules per kelvin per mole T= temperature (kelvin)
What is a mole ?
A unit used for mass. Can be measured in grams of dm cubed for concentration.
How many miles in 1 litre of water ?
55.6
How do you calculate number of miles ? Use units
Number of moles = mass (grams)/ relative atomic or molecular mass.
What are relative atomic and molecular mass measured in ?
RAMS
What is relative isotopic mass ?
Is the ratio of the mass of one atom of that isotope to the mass of 1/12th the mass of Carbon-12.
Why is relative isotopic mass never a whole number ?
The masses of protons and neutrons vary in every isotope.
What is relative atomic mass ?
The ratio of the average mass of one atom of that element to 1/12th the mass of Carbon-12.
What is relative molecular mass?
The ratio of the average mass of that molecule to 1/12 the mass of Carbon-12.
How do you calculate relative atomic mass ?
(Average mass of one atom/ mass of one atom of carbon-12) x100
What is 1 unit of charge in coulombs ?
1.602x10^-19
What is one unit of mass in atomic mass units ?
1.661x10^-27 kg
What is an atomic mass unit ?
1/12th of the mass of Carbon-12
What is mass number?
The sum of the number of protons and neutrons in an atom.
What is a neutral atom ?
An atom with the same number of protons and electrons and therefore no overall charge.
What are isotopes?
Versions of The same atom because they have the same number of protons and electrons but a different number of neutrons.
What are protons and neutrons collectively called ?
Nucleons.
What is the standard nucleus in chemistry ?
Carbon- 12
What is one mole of any Gas in dm cubes ? And in what conditions (pressure/temperature)?
24 dm cubed
At 100 kilo pascals and 298 kelvin
How is percentage yield calculated ?
(Actual mass / theoretical mas) x100
What is the importance of obtaining a high yield ?
It makes the process more sustainable and less harmful to the environment because we reduce the waste of reactants and the cost of the process.
Why may percentage yield be below 100%.
Reversible reaction where some products have re-reacted to form the initial reactants.
Not all reactants have reacted.
Loss of product whilst filtering, transferring liquids or etc.
Why may a percentage yield be above 100% ?
When the actual mass given is incorrect.
What is a precipitation reaction ?
When a solid has been produced.
What is the purpose of ionic equations ?
They remove ions which could over complicate the chemistry of the reaction.
What are spectator ions ?
Ions that are removed in ionic equations.
What is an aqueous substance ?
When the solid is dissolved in water , the ions dissociate.
What state are acids ?
Acids are aqueous despite being non-metals
What is the charge of all solids ?
Zero. They have no charge
What is a limiting reagent ?
The substance which stops the reaction going any further because you no longer have enough of it.
What is the conservation of mass ?
Weight of reactants = weight of products.
What substances are in ionic and covalent bonds ?
Ionic = metal and non-metal. Covalent = non-metals.
What is made when organic compounds are burnt in oxygen and give an example of an organic compound.
Hydrocarbons
Carbon dioxide and water.
How do you find the number of molecules or particles using avagados constant ?
Avagados constant x number of atoms
How do you find the number of miles of a substance using avagados constant ?
Number of particles / avagados constant.
What is meant by relative abundance ?
The % of that isotope that occurs in nature.
Name 3 reasons why a reaction may be less than the theoretical yield ?
Unwanted products formed (by-products)
Some left in the reaction vessel
Impure reactants
How is % atom economy calculated ?
(Mass of desired products/total mass of reactants) x100
What does atom economy mean ?
The % of the total mass of reactants that can be converted into the desired products.
What does atom economy mean ?
The % of the total mass of reactants that can be converted into the desired products.
What is 1 atmosphere in pascals.
101325
What must you add to degrees celcius to get degrees Kelvin ?
273
What is 1 Kpa in Pa ?
1000 Pa
What is an ideal gas ?
A gas in which the particles show no attraction for each other and also have no volume.
When is ideal gas behaviour most likely?
High temperatures and low pressures.
What is 1m3 in dm3 and cm3
1m3=1000dm3=1000000cm3
How do you convert cm cubes to m cubed ?
Divide by 1000000
How do you convert decimetres cubes into meters cubes ?
Divide by 1000
What must you do to covert degrees Celsius into degrees kelvin ?
+273
What is an ideal gas ?
A gas with particles that show no attraction for each other and also have no volume.
When is ideal gas behaviour most likely ?
At high temperatures but low pressure.
What is the equation to work out density ?
Mass divided by volume
What is the equation to work out number of moles ?
Mass divided by Mr
How do you calculate density using the ideal gas equation ?
(P x Mr) / (R x T)
What is the value of the gas constant ?
8.31
How is density calculated and what are it’s units ?
Mass / volume
Grams per decimetre cubed
How is number of moles calculates ?
Mass / Mr
How is mass calculates ?
Moles x Mr
What is the definition for concentration ?
And what units is this in. ?
The amount of solute present in a fixed quantity of solvent or solution.
In grams per decimetre cubed.
What is molarity and what are it’s units ?
Concentration in mol per decimetre cubed.
What is the definition of standard ?
Solution whose concentration is known accurately.
How do you calculate number of molecules ?
Moles x avagados constant
How’s is cm cubes converted to dm cubed ?
Divide by 1000
How is m3 converted into dm3 ?
X 1000
Draw the triangle for calculating concentration.
Moles on the top.
Volume and concentration on the bottom.
What is concentration measured in ?
Grams per decimetre cubed.
What are the units of Mr
Grams per mol
How do you convert cm cubes to m cubed ?
Divide by 1000000
How do you convert decimetres cubes into meters cubes ?
Divide by 1000
What must you do to covert degrees Celsius into degrees kelvin ?
+273
What is an ideal gas ?
A gas with particles that show no attraction for each other and also have no volume.
When is ideal gas behaviour most likely ?
At high temperatures but low pressure.
What is the equation to work out density ?
Mass divided by volume
What is the equation to work out number of moles ?
Mass divided by Mr
What is the definition for concentration ?
The amount of solute present in a fixed quantity of solvent or solution (g/dm3).
What is molarity ?
Concentration measured in mol/dm3
What is a standard ?
A solution whose concentration is known accurately.
How do you convert cm to dm ??
X1000
How’s do you calculate number of moles in dm3 ?
Mass / Mr
How do you convert concentration from mol / dm3 to grams/dm3 ?
Concentration in molarity x Mr
How do you convert concentration in grams per dm2into concentration in mol per dm3 ?
Concentration in g/dm3 divides by Mr
What is a neutralisation reaction and which ions are involved ?
The reaction of an acid and an alkali where the H+ ions from the acid react with the OH- ions from the alkali to create a salt and a water.
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