Chemistry Final Study
Periodic Table Trends:
Atomic Radius - half of the distance between the centers of two atoms that are touching each other decreases moving left to right increases moving top to bottom
Ionization Energy - energy required to remove an electron increases moving left to right decreases moving top to bottom
Electron Affinity - ability to accept an electron alkaline earth elements have low electron affinities halogens have high electron affinities noble gases have electron affinities near zero other element groups tend to have low electron affinities
Electronegativity - measure of the attraction to form a chemical bond increases moving left to right decreases moving top to bottom
Stoichiometry:
Balance the equation.
Convert units of a given substance to moles.
Using the mole ratio, calculate the moles of substance yielded by the reaction.
Convert moles of wanted substance to desired units.
Converting from Grams to Moles
NOTE: One mole of anything contains 6.022 x 1023 atoms
Atomic weights on the periodic table are given in terms of amu (atomic mass units), but, by design, amu correspond to the gram formula mass. In other words, a mole of a 12 amu carbon atom will weigh 12 grams.
The gram formula mass can be used as a conversion factor in stoichiometric calculations through the following equation:
Moles =
Converting between Volume of a Gas and Moles
The Ideal Gas Law is PV = nRT , with nrepresenting the number of moles. n =
Mass to Moles
Moles to Mass (same!)
Atoms to Mass
Divide by 6.022x10^23, then multiply by atomic mas
To convert mass to atoms:
Find the atomic mass of the element in the substance. You can find atomic masses on the periodic table. Ex. Lithium's atomic mass is 6.9 grams (round if you need to)
Then find the mass of the substance in grams. Ex. you have 18.2 grams of a sample of Lithium.
The mass of the sample is multiplied by 6.02 * 1023 and divided by the atomic mass.
Ex.
mass of
Atomic Radius - half of the distance between the centers of two atoms that are touching each other decreases moving left to right increases moving top to bottom
Ionization Energy - energy required to remove an electron increases moving left to right decreases moving top to bottom
Electron Affinity - ability to accept an electron alkaline earth elements have low electron affinities halogens have high electron affinities noble gases have electron affinities near zero other element groups tend to have low electron affinities
Electronegativity - measure of the attraction to form a chemical bond increases moving left to right decreases moving top to bottom
Stoichiometry:
Balance the equation.
Convert units of a given substance to moles.
Using the mole ratio, calculate the moles of substance yielded by the reaction.
Convert moles of wanted substance to desired units.
Converting from Grams to Moles
NOTE: One mole of anything contains 6.022 x 1023 atoms
Atomic weights on the periodic table are given in terms of amu (atomic mass units), but, by design, amu correspond to the gram formula mass. In other words, a mole of a 12 amu carbon atom will weigh 12 grams.
The gram formula mass can be used as a conversion factor in stoichiometric calculations through the following equation:
Moles =
Converting between Volume of a Gas and Moles
The Ideal Gas Law is PV = nRT , with nrepresenting the number of moles. n =
Mass to Moles
Moles to Mass (same!)
Atoms to Mass
Divide by 6.022x10^23, then multiply by atomic mas
To convert mass to atoms:
Find the atomic mass of the element in the substance. You can find atomic masses on the periodic table. Ex. Lithium's atomic mass is 6.9 grams (round if you need to)
Then find the mass of the substance in grams. Ex. you have 18.2 grams of a sample of Lithium.
The mass of the sample is multiplied by 6.02 * 1023 and divided by the atomic mass.
Ex.
mass of