Chapter 2: Amount of substance
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What is the Avogadro constant?
6.022 × 10^23 mol-1
What is a mole? And what is the equation of it?
The amount of substance that contains 6.022x10^23 particles. Mole(n) = Mass (g) / Mr
what is the Concentration formula?
Concentration (mold dm^-3) = Moles (n) / Volume (dm^3)
What is the Ideal Gas Equation?
pV = nRT Where p = Pressure in Pa, standard pressure = 100,000 Pa V = Volume in meters cubed n = Number of moles of gas R = The Ideal Gas Constant at 8.31 J/K/mol T = Temperature in K, standard temprature = 298K(25°C)
What does PV equal?
PV = nRT
What is the Empirical formula?
Number of moles = mass of element / mass of 1 mole of element
Find the empirical formula of clacium carbonate 10.1 g of a white solid contains: • 4.01 g of calcium, • 1.20g of carbon, • 4.80 g of oxygen Ar = Ca(40.1) C(12.0) O(16.0)
moles of calcium = 4.01 / 40.1 = 0.1 moles of carbon = 1.2 / 12 = 0.1 moles of oxygen = 4.8 / 16.0 = 0.3 therefore the ratio is calcium : carbon: oxygen: 1 : 1 : 3 = CaCO3
What is the molecular Formula?
The molecular formula is the number of atoms of each element in 1 molecule of a compound.
The Emprical formula of compound x is x also has an Mr of 58 C : H : O 3 : 6 : 1 Find the molecular formula.
The Mr of C : H : O = 58 Therefore the molecular formula is also C3H6O
What is the equation for moles
Mole = Mass/Mr
What is the equation for atom economy?
% atom economy = Mass of desired product total mass of reactants x100
Find the atom econmy of sodium chlorate in: 2NaOH + CL2 → NaCl + H2O + NaOCl Mr of Na = 23 Mr of Cl = 35.5 Mr of O = 16 Mr of H = 1
Moles = 2 : 1 → 1 : 1 : 1 Therefore the masses must = 80g : 71g → 58.5g : 18g : 74.5g % atom economy = 74.5/151 x 100 = 49.3%
What is the formula for percentage yield?
percentage yield = Number of moles of product max nubmber of moles of the product x100