Amount of Substance Flashcards
What is the definition of relative atomic mass?
The relative atomic mass (Ar) is the weighted average of an element, taking into account its naturally occurring isotopes, relative to 1/12 the relative atomic mass of an atom of carbon 12.
What is the relative molecular mass of a molecule?
The Mr of a molecule is the mass of that molecule compared to 1/12 the relative atomic mass of an atom of carbon 12.
What is relative formula mass?
It is used for ionic compounds because they don’t exist as molecules.
What is the Avogadro constant?
The number of particles in one mole of any element which is 6.022x10(23). Is described as the number of atoms in 12g of carbon-12.
What is a mole?
The amount of a substance that contains 6.022x10(23) particles.
What is the formula for mass moles and Mr?
Mass=mr x moles
What does a solution contain?
A solvent with a solute dissolved in it.
What is the formula for finding the concentration of a solution?
concentration=moles/volume(dm3)
What is the ideal gas equation?
PV=nRT (R stands for the gas constant which is 8.31)
What must the units be for the ideal gas equation?
P= pascals
V=m3
T= kelvin
What is Boyles law?
The product of pressure times volume is constant as long as the temp. remains the same.
To find out how to do empirical formula….
Look in amount of substance booklet for instructions
How to find the molecular formula
You look at the relative molecular mass and see the amount empirical formula is off by e.g empirical formula adds to 12 but the Mr is 48 so you’d times each component of empirical formula by two to get the molecular formula.
