Atom, Elements And Molecules Flashcards
Define atom
A smallest unit of an element that still has the properties of an element
Define element
A substance that is made up of only one type of atom
Define ion
An atom or a group of atoms that have positive or negative charge
Define molecule
A group of atoms that are chemically bonded together
Define compound
A group of atoms that consists of two or more types of atoms bonded together
Define empirical formula
The simplest whole number ratio of atoms of each element in a compound
Define molecular formula
The actual number of atoms of each element present in a compound
Define mole
The amount of any substance containing the same number of particles asa there are atoms in exactly 12g of carbon-12
Define the avogadro constant
The number of particles in one mole of a substance . This is 6.02x10^23 particles
Equation of avogadros constant to moles
Number of particles = moles x avogadro constant
Define relative atomic mass
The weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon -12
Define relative formula mass
The sum of the relative atomic masses of atom in a formula unit
Define relative molecular mass
The sum of the relative atomic masses of atom on a molecule
Define ppm
Parts per million
The ratio of one gas to another
Define concentration
Is the amount of solute dissolved per dm^3 of solution
How can concentration be calculated in g dm^3
Concentration (g dm^3) = mass(g) / volume (dm^3)
Concentration be calculated mol dm^3
Concentration = moles / volume (dm^3)
Calculate number of moles of a goven substance using the mass and molecular mass
Number of moles = mass/ relative molecular mass
What the equation links molar volume at RTP and moles
Volume of gas at RTP (dm^3) = moles x 24
Ideal gas law
PV = nRT
P-pressure (pascal) V - volume (m^3) n ( moles) R- gas constant (8.31 J K mol^-1) T temperature ( kelvin)
How can percentage yield be calculated
Percentage yield = (actual yield) divide theoretical yield) x 100
Why might the actual yield of product be less than expected
- incomplete reaction
- unwanted side reactions
- practical losses
What is atom economy of a reaction
Atom economy is a measure of the efficiencyof the reaction. It looks at the amount of reactant that get turned into useful products
How can atom economy be calculated
Atom economy = (molar mass of desired product) divide (total molar mass of products) x 100
The ____ the atom economy, the more sustainable and efficient the process
Higher
What are displacement receaction
