Chem chapter 5 (Chemical Calculations) Flashcards
What is mole?
The term is used to talk about the mass. The mass of a mole of a substance is the mass of its relative atomic mass in grams.
What is the number for Avogadro’s constant
6.022 x 10^23
Symbol for Avogadros constant
NA
Formula for number of particles
Moles x Avogadro’s number
Formulas for mole
Mass/ Molar mass
Number of particles/ Avogadro’s number
Volume/Volume at RTP
Concentration * Volume
How many moles are there in 60g of sodium hydroxide
60/40= 1.5
What is the mass of 0.5 mol of hydrated copper sulfate crystals?
249.685x0.5= 124.75
What is the formula for percentage of atom in molecule
Relative atomic mass/ Relative formula mass X 100
Define Avogadro’s law
Equal volumes of gas are found to contain the same number of particles
How much space does one mole of any gas occupy
24dm³
How much is 24dm³
24 litres
What does S.T.P stand for
Standard temperature pressure
How much is the standard temperature pressure
0⁰C
What does R.T.P stand for
Room temperature pressure
Define the Law of conservation of mass?
The mass of products is equal to the total mass of the reactants.
Why are balanced equations useful?
The balanced equation for a chemical reaction shows the ratio of reactants and products involved
Define percentage yield?
It shows how much product was actually made compared with the amount of product that was expected
Define theoretical yield?
It is the maximum mass of product expected from the reaction, using reacting masses
Define actual yield?
It is the mass of the product that is actually obtained from the real chemical reaction/experiment.
What is the equation for the percentage yield?
Actual yield / Theoretical yield * 100
Equation for percentage purity?
Mass of pure product / Mass of impure product * 100
What does R.F.M stand for?
Relative formula mass
What is R.A.M?
Relative Atomic mass
What is the formula for percentage composition/percentage by mass of an element?
R.A.M * Number of atoms / R.F.M of compound * 100
