Chapter 3 Amount of substance Flashcards
What is relative molecular mass?
relative molecular mass compares the mass of a molecule with the mass of an atom of carbon-12
What is relative formula mass?
relative formula mass compares the mass of a formula with the mass of an atom of carbon-12
What is ‘Amount of substance’
The number of particles in a substance measuring in a unit called mole
What is one mole?
The amount of a substance that contains (6.02x10^23) particles
What is Avogardro’s constant?
6.02x10^23 –> the number of particles in each mole of carbon-12
What is Molar mass?
The mass per mole of a substance and gives a convient way of linking moles with mass for any chemical substance
What is the equation for Amount of substance using Molar mass?
Amount of substance = mass / Molar mass
What is the molecular formula?
The number of atoms of each element in a molecule
What is the empirical formula?
The simplest whole-number ratio of atoms of each element in a compound
What is molar gas volume?
The volume per mole of gas molecules at a stated temperature and pressure
What are the two assumptions when calculating the formula of a hydrated salt?
Assumption 1 - All of the water has been lost
Assumption 2 - No further decomposition
What is water of crystallisation?
The water in a lattice
What is the equation for Amount of stubstance using Concentration?
Amount of substance = Concentration X Volume(dm3)
What is standard solution?
A solution of known concentration
What is molar gas volume?
The volume per mole of gas molecules at a stated temperature and pressure
What is the equation for Amount of substance using Molar gas volume?
Amount of substance = Volume / Molar gas volume
What is the Ideal gas equation
pV = nRT
What does (p) represent in the ideal gas equation?
Pressure measured in Pa
What does (V) represent in the ideal gas equation?
Volume measured in m3
What does (n) represent in the ideal gas equation?
amount of gas molecules measured in mol
What does (R) represent in the ideal gas equation?
Constant of 8.314
What does (T) represent in the ideal gas equation?
Temperature measured in K
What is theoretical yield?
The maximum possible amount of product
What are the 3 main factors affecting theoretical yield?
- The reaction may not have gone to completion
- Other reactions may have taken place alongside the main reaction
- Purification of the product may lresult in loss of some product
What is the equation for percentage yield?
Percentage yield = (Actual yield / Theoretical yield) x 100
In a reaction, what is a limiting reagent?
The reactant that is not in excess and will be completely used up first and stop the reaction
What is atom economy?
A measure of how well atoms have been utilised
What is the equation for calcualting atom economy?
Atom economy = (Sum of molar masses of desired products / Sum of molar masses of all products) x 100
