Amounts of Substances Flashcards
(27 cards)
What is a mole
The amount of a substance that contains the same number of particles as there are carbon atoms in 12 grams of carbon-12
What does 1 moles of a substance correspond to
The relative atomic/molecular/formula mass
What is Avogadro’s number
The number of particles in one mole of a substance is 6.02 x 10^23
How can you calculate the number of particles in a substance
Number of moles x Avogadro’s number
What is molar mass
The mass of one mole of a substance
How are mass, molar mass and moles related
Mass = molar mass x number of moles
What is the law of conservation of mass
The total combined mass of the reactants must be the same as the total combined mass of the products
Why must masses be converted into moles to be compared
Because the ratio in which species react corresponds to the number of moles, not their mass
What is a quantative reaction
One that does not go to completion
What is the definition of percentage yield
The amount of product formed in a reaction that does not go to completion compared to the amount of product that could be formed if it did complete
How do you calculate the percentage yield
Amount of product formed divided by maximum amount of product possible x100
What is the definition of atom economy
The percentage of the total mass of reactants that can, in theory, be converted into the desired product
How do you calculate atom economy
Mass of desired product divided by total mass of products x100
What is a solution
A mixture of two or more substances in which the proportions of the substances are identical throughout
What are the solvent and solutes in a solution
The solvent is the major component and the solute in the minor component
What is concentration
The amount of solute present in a solvent
How can you calculate moles from volume and concentration
Moles = Volume (dm3) x concentration
What is volumetric analysis
The investigation of chemical reactions by comparing reacting volumes- done through titration
What happens in titration
A solution with a know concentration is titrated against a solution who’s concentration is not known,
The known solution is always in the burette and the unknow solution is always in the conical flask
What does the volume occupied by a gas depend on
Temperature,
pressure and the amount of gas
What is the ideal gas equation
PV=nRT
P= pressure in Pa
V= volume in m3
T= temperature in K
R= molar gas constant
How to calculate percentage purity
Mass substance would have if pure over mass of impure substance x 100
What is empirical formula
The formula of a compound which shows the simplest whole number ratio in which the atoms in the compound exist
What is the molecular formula
The formula which shows the number of each type of atom in one molecule of that substance
