Chapter 4 and 5 Reacting masses and Moles Flashcards
What does AR stand for
Relative atomic mass
AR definition
average mass of its isotopes, compared to 1/12th the mass of the carbon-12 atom.
2 laws of chemistry
Elements will always react in the same ratio to form a given compound
Total mass does not change
Therefore, mass of reactants = mass of products
What is a pure substance
A substance that only contains the particles shown in its formula
Purity formula (%)
(Mass of pure products)/(Total mass) * 100
What is one mole of particles (explanation)
Number of particles obtained by weighing out the Ar or Mr of the substance in grams.
What is the Avogadro constant
6.02*10^23
Symbol for 1 mole
mol
How many particles does 1 mol of a substance have??
1 mol of a substance has 6.02*10^23 particles in it
Formula of to find number of moles
number of mols = mass/MR
number of mols = Volume at atp/24 dm^3 (only gasses)
number of mols = concentration * volume
What is RTP
Room temperature (20 C) and pressure
Avogadro’s law
1 mole of every gas has the same volume. at RTP that volume is 24 dm^3
What is the concentration of a solution
2 units
Amount of solute that is dissolved in 1 dm^3 of solution.
mol/dm^3 or g/dm^3
What is the empirical formula
Simplest WHOLE NUMBER ratio in which atoms combine
What is the molecular formula
the ACTUAL whole number ratio in which atoms combine
Empirical mass
Mass calculated using the empirical formula
cm^3 to dm^3
divide by 1000
how to find no. of moles with volume and conc
mol = conc x vol
what is the molar volume constant
24
how to find vol of a substance
no of moles = vol given/24
