Module 2: Chapter 3- Amount of substance Flashcards
What is the amount of substance?
The amount of substance refers to the measurement of the number of entities (atoms, molecules, ions, etc.) in a chemical substance. It’s usually expressed in units of moles
What is the mole?
The mole is the unit of measurement for the amount of substance. It’s defined as the number of entities (atoms, molecules, ions, etc.) in a substance that is equal to Avogadro’s number.
What is Avogadros constant
6.022 × 10²³
How do you calculate the number of moles in a substance?
Number of moles = Mass of substance (in grams) / Molar mass (mr) (in grams/mol)
How do you calculate the molar gas volume in a substance?
Amount of gas (moles) = Volume (dm³)/ 24 (dm³)
What is the empirical formula
simplest whole-number ratio of atoms in a compound
What is the molecular formula
the actual number of atoms of each element in a molecule of the compound.
Define anhydrous
free from water and especially water of crystallization
Define hydrated
A substance is hydrated if water, or the elements of water (hydrogen and oxygen in the ratio of 2:1), is added to it.
How to work out the mass of water in terms of hydrated and anhyrous
mass of water = mass of hydrate - mass of adhydrous
What is water of crystalisation
Water of crystallisation is when some compounds can form crystals which have water as part of their structure
What is the equation that links concentration and volume
moles of substance = volume of liquid (in litres) × concentration (in mol/L)
What is the ideal gas equation
pV = nRT
p = pressure
v = volume
n = moles
R = gas constant
T = temp
What is the equation for percentage yield
Percentage yield = (actual yield / theoretical yield) x 100
What is the eqation for atom economy
Percentage atom economy = (Total number of atoms in desired product / Total number of atoms in starting material) x 100
