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.