Moles

Question 1

what are the polyatomic ions?

Answer 1

• nitrate, NO3-
• carbonate, CO32-
• sulfate, SO42-
• ammonium, NH4+
• hydroxide, OH-

Question 2

what are the steps in solving ionic equations?

Answer 2

1) ensure that the equation is balanced with state symbols
2) write the aqueous species as ions
3) solid, liquid and gas species should be left as they are
4) cancel the ions that appear on both side of the equation

Question 3

define relative atomic mass (Ar)

Answer 3

the average mass of on eaton of the element when compared with 1/12 of the mass of an atom of carbon-12

Question 4

define relative molecular mass (Mr)

Answer 4

the average mass of one molecule of a substance when compared with 1/12 of the mass of an atom of carbon-12

Question 5

what are the steps in solving mole questions?

Answer 5

1) find the number of moles
2) compare mole ratio
3) answer the question

Question 6

what is the mass formula?

Answer 6

mass = mol x Ar or Mr

Question 7

what is the mol formula?

Answer 7

mol = vol in dm3 x conc (mol/dm3)

Question 8

what is the volume of gas at r.t.p formula?

Answer 8

vol of gas at r.t.p = mol x 24dm3

Question 9

what is the conc (g/dm3) formula?

Answer 9

conc (g/dm3) = conc (mol/dm3) x Mr

Question 10

what is the mass formula?

Answer 10

mass = conc (g/dm3) x vol in dm3