Chapter 3 - Amount of substance Flashcards
What is the Avogadro’s Constant?
6.02x10*23
AND it is the number of particles in each mole of carbon-12
Define Molar Mass.
Molar Mass gives the mass in grams in each mole of the substance.
State the equation which links moles, mass and molar mass.
Moles(n) = mass(m) / molar mass(M)
What is the Empirical formula?
Simplest whole-number ratio of atoms of each element within a compound.
Define Relative Formula Mass.
The compared mass of a formula unit with the mass of an atom of carbon-12
What is the name given to a crystal that contains water molecules?
They are known as hydrated crystals.
What is this water called?
Water of Crystallisation
State the equation that links moles, volume and concentration.
moles(n) = concentration(mol dm3) x volume(dm3)
OR
moles(n) = concentration(mol dm3) x volume(cm3)/1000
What is a Standard Solution?
A solution of known concentration
Define Molar Gas Volume.
The volume per mole of gas molecules at a stated temperature and pressure.
What volume does 1 mole of gas occupy at room temperature and pressure?
24.0 dm3 OR 24,000 cm3
What are the values of room temperature and pressure?
Around 20 Degrees Celsius and 101 kPa (1 atm) pressure
State the Ideal Gas Equation AND what each part stands for.
pV = nRT p = pressure (Pa) V = volume (m*3) n = amount of gas molecule (mol) R = ideal gas constant (8.31 J/mol/K) T = Temperature (K)
Why is it difficult to achieve a maximum theoretical yield?
- the reaction may not have gone to completion
- purification of product may result in loss of some
product - other reactions (side reaction) may have taken place
alongside the main reaction
What is the equation used to calculate percentage yield?
Percentage yield = actual yield / theoretical yield x 100
