Sign in for Chemistry Exercise with explanation and answers
Let say we have 100 ml of H2SO4 solution and it contains 0.49 g of H2SO4
What is Molarity?
What is Normality?
1 Molar solution contains number of gram equals to molecular mass per one liter.
MW of H2SO4 = 2 + 32 + 4* 16 = 98
I mole = 98g/L
We have to find how many gram of H2SO4 given solution contains
100 ml = 0.1 L and contains 0.49 g
1 L contains X g X = 0.49 * 1 / 0.1 = 4.9 g.
98g/L - 1 Mole
4.9 g/L - X Mole X = 4.9 * 1 / 98 = 0.05 Mole
Molarity of 100 ml solution of H2SO4, which contains 0.49 g of H2SO4 equals 0.05 Mole.
What is normality? An equivalent is the molecular mass or mass of acid or base that produce one mole of protons (H+) or one mole of hydroxyl (OH-) ions.
One mole of H2SO4 produces 2 moles of H+ then equivalent of H2SO4 = MW/2 = 49g/L
49g/L is 1 N solution
4.9g/L solution is - X N X= 4.9 * 1/ 49 = 0.10 N.
Normality of 100 ml solution of H2SO4, which contains 0.49 g of H2SO4 equals 0.10 N.
2. We have 10 ml of NaOH unknown concentration. The solution was titrated with 0.10 N solution of H2SO4 and 15 ml were required for neutralization. What is concentration of NaOH?
Nb * Vb = Na * Va where V is volum, N is Normality, b - base and a - acid
Nb = Na * Va / Vb = 0.10 * 15 / 10 = 0.15 N
Concentration of NaOH = 0.15 N.
2H20 = 2H2 + 02
1 L ?L
Question: How many liters of Hydrogen are produced from one liter of water?
First, we have to find how many grams of water spent and how many grams of H2 produced?
MW of H20 = 2 + 16 = 18 We spent 2 molecules of H20 then we spent 18 * 2 =36 g.
MW H2 = 2 and we got 2 molecules of H2. 2*2 = 4g
36 g of water produces 4 g of Hydrogen
1000 g of water produces X g of Hydrogen. X = 4 * 100 / 36 = 111.1 g
I mole of Gas under normal conditions occupies 22.4 liters. So we have to know how many mole of H2 is produced.
1 mole of H2 equals 2 g
X mole of H2 equals 111.1g
X = 111.1g / 2g = 50.6 Mole of H2
1 mole of H2 occupies 22.4 liters
50.6 mole of H2 occupies X liters
X = 50.6 Mole * 22.4L = 1232 L
My chemistry tutorial is focused on key chemistry topics: Oxides, Bases, Acids, Salts, Equivalent proportions, Acid Base reactions, Weigh and Volume problems, Equilibrium, Le Chatelier's Principle, Liquid Properties: Freezing and Boiling points, Balance Redox Reactions (30 examples with explanations), Stoichiometry (30 problems with answers and solutions). Study my tutorial and you will understand chemistry.