compositions of substances and solutions

Question 1

determination of empirical formulas from % composition data

Answer 1

1. convert percent compostion to masses of elements by assuming 100g sample of compound
2. convert element masses to moles using molar masses
3. divide each number of moles by the smallest number of moles
4. if necessary, multiply by an integer, to give the smallest whole number ratio of subscripts

Question 2

determination of empirical formulas from masses of its elements

Answer 2

1. convert element masses to moles using molar masses
2. divide each number of moles by the smallest number of moles
3. if necessary, multiply by an integer, to give the smallest whole number ratio subscripts

Question 3

dervation of molecular formulas

Answer 3

(molecular or molar mass)/(empirical formula mass) = n formula (units)/(molecule)

Question 4

`

Question 5

dilution

Answer 5

the process where by the concentration of a solution is lessened by the addition of solvent

Question 6

Molarity (M)

Answer 6

the number of moles of solute in exactly 1 liter (1L) of the solution

M= (molsolute)/(L solution)

Question 7

solutions

concentrating

Answer 7

• a homogeneous mixture- uniform composition and properties troughout its entire volume
• amount of a given solution component

Question 8

solvent

solute

aqueous solution

Answer 8

• component with a concentration that is significantly greater than that of all other components
• component that is typically preent at a much lower concentration than the solvent
• a solution in which water is the solvent