The mole concept

Question 1

What are spectator ions?

Answer 1

are ions that play no part in the reaction

Question 2

List the state symbols for elements

Answer 2

(s)-solid
(l)-liquid
(g)-gas
(aq)-aqueous solution

Question 3

What is the definition of a mole?

Answer 3

is the amount of substance which has the same number of specified particles as there are atoms in exactly 12g of the 12C isotope

Question 4

What’s the molar mass(M) and the unit of M?

Answer 4

is the mass of 1 mole of a substance in grams

M= gmol-1

Question 5

How can we find the number of moles?

Answer 5

mol= mass of substance/molar mass

Question 6

What can the mole concept be used to do?

Answer 6

to calculate the masses of reactants required to form a specific mass of products or the mass of specified products formed from a given mass of reactants

Question 7

What is the empirical formula and how can it be deduced?

Answer 7

shows the simplest whole number ratio of atoms in a compound.

using masses or relative masses of the elements present in a compound

Question 8

What is the molecular formula and how can it be deduced?

Answer 8

shows the total number of atoms present in a formula unit of a compound

can be deduced if the relative molecular mass of the compound is known

Question 9

What does avogadros law state? and what does it deduce?

Answer 9

that equal volumes of all gases at the same temperature and pressure contain the same number of molecules

stoichiometry of a reaction and the molecular formula of a simple molecular compound

Question 10

What’s the formula for the molar concentration?

Answer 10

mol dm-3= number of moles of solute/volume of solution

Question 11

What is a titration? and how are acid bases titration done?

Answer 11

is used to determine the amount of substance present in a solution of unknown concentration

using an indicator which changes colour rapidly at the end point