Any chemical reaction go both way
According to Le Chatelier, the position of equilibrium will move to counteract the change.
If reaction produces heat then heating the system will move equilibrium to the left
And cooling the system will move equilibrium to the right. If volume of the products is
greater than volume of the reactants then increasing the pressure will move equilibrium to the left.
Decreasing pressure will move equilibrium to the right. Increasing concentration of reactants will
move equilibrium to the right, increasing concentration of the products will move equilibrium to
the left.
Equilibrium constant Keq = [C] * [D] / [A] * [B] where [ ] is concentration in Moles
2H2S <=> 2H2 + S2 concentration of products and reactants is raised to the power of their respective coefficients.
Keq = [H2]2 * [S2] / [H2S]2
pH Acidity or Basicity of a solution.
PH = -Log [H+] where [H+] is concentration of H+ ions.
What is log? log is logarithm with base 10. Log 10 = 1 because 101 = 10
Log100 = 2 because 102 = 100. Log 1000 = 3 because 103 = 1000
log1/1000 = -3 because 10-3 = 1/1000
- log 1/1000 = 3.
pH of water is 7 (neutral)
What is pH of 0.0001 N HCl?
HCl = H+ + Cl-
Concentration of H+ equals concentration of HCl = 0.0001 N
pH = - log [1 * 10-4] = 4
Freezing point constant = degree C per 1M of solute per 1000g of solvent.
For water Fpk = 1.86
Given: 1 M of NaCl solution. What is freezing point?
Pt = Molarity * Fpk = 1 * 1.86 = 1.86 C
Freezing point of water is 0 C then freezing point of solution = 0 C - 1.86 C = -1.86 C
Given: 196 g of H2SO4 added to 500 g of water. What is freezing point of the solution?
How many mole of H2SO4 is in 196g? MW = 2+32+64=98g
196g/98g = 2 M. is in 500g
X M is in 1000g X = 2 * 1000 / 500 = 4 M
Fr p. depression =4 M * 1.86 C = 7.44 C
Frp = 0 C - 7.44C = -7.44 C Where 0C Freezing point of water.
Boiling point depends on number of solute particles per number of solvent particles.
For water Kb = 0.52
Given: 106 g Na2CO3 in 500 g of water. What is boiling point of the solution?
MW of Na2CO3= 23+23+12+48 = 106
106 g in 500 g water
Xg in 1000g water X = 106 * 1000 / 500 = 212 g
106 g/L - 1 M
212 g/L - X M X = 212 / 106 = 2 M.
Bp. raise = 2 M * 0.52 = 1.4 C Bp = 100 C + 1.4 C = 101.4 C
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.