ALEKS COMPLETE TEST REVIEW WITH
FULL SOLUTIONS
●● mass to moles conversion
Answer: weight/molar mass (found on periodic table) = moles
●● sig fig rules
Answer: 1) non-zero digits and zeros in-between them are sig figs
2) leading zeros (0.04) are not sig figs (start counting SF at first non-
zero number)
3) trailing zeros with a decimal are sig figs (without a decimal are not
4) when multiplying/dividing by measurements, answer must have same
number of sig fig as measurement with least number of sig fig
●● scientific notation
Answer: A method of writing or displaying numbers in terms of a
decimal number between 1 and 10 multiplied by a power of 10.
●● isotopes
Answer: Atoms of the same element that have different numbers of
neutrons (proton number stays the same always!!!)
●● ionic compounds
, Answer: compounds composed of cations and anions (typically metals
and non-metals together)
●● how to find binary ionic compounds when given 2 cations and 2
anions
Answer: create a table with cations on top, anions on the side, and pair
the elements up while balancing charges to have a net charge of 0,
similar to punnett squares) *subscripts on elements always end up being
absolute value of the opposite element's charge*
●● calculating mass density
Answer: use D = M/V (1 cm^3 = 1mL)
●● prefixes for naming molecular (covalent) compounds
Answer: mono 1, di 2, tri 3, tetra 4, penta 5, hexa 6, repta 7, octa 8, nona
9, deca 10 (ex. carbon dioxide)
●● finding molar mass from chemical formula
Answer: find the molar mass of each element, multiply those masses by
as many atoms of each element you have in the formula, add up all
masses
●● balancing chemical equations made easy
Answer: ATOMS CANNOT BE CREATED OR DESTROYED - steps:
FULL SOLUTIONS
●● mass to moles conversion
Answer: weight/molar mass (found on periodic table) = moles
●● sig fig rules
Answer: 1) non-zero digits and zeros in-between them are sig figs
2) leading zeros (0.04) are not sig figs (start counting SF at first non-
zero number)
3) trailing zeros with a decimal are sig figs (without a decimal are not
4) when multiplying/dividing by measurements, answer must have same
number of sig fig as measurement with least number of sig fig
●● scientific notation
Answer: A method of writing or displaying numbers in terms of a
decimal number between 1 and 10 multiplied by a power of 10.
●● isotopes
Answer: Atoms of the same element that have different numbers of
neutrons (proton number stays the same always!!!)
●● ionic compounds
, Answer: compounds composed of cations and anions (typically metals
and non-metals together)
●● how to find binary ionic compounds when given 2 cations and 2
anions
Answer: create a table with cations on top, anions on the side, and pair
the elements up while balancing charges to have a net charge of 0,
similar to punnett squares) *subscripts on elements always end up being
absolute value of the opposite element's charge*
●● calculating mass density
Answer: use D = M/V (1 cm^3 = 1mL)
●● prefixes for naming molecular (covalent) compounds
Answer: mono 1, di 2, tri 3, tetra 4, penta 5, hexa 6, repta 7, octa 8, nona
9, deca 10 (ex. carbon dioxide)
●● finding molar mass from chemical formula
Answer: find the molar mass of each element, multiply those masses by
as many atoms of each element you have in the formula, add up all
masses
●● balancing chemical equations made easy
Answer: ATOMS CANNOT BE CREATED OR DESTROYED - steps:
