Chemistry:solution 1

SOLUTION AND ITS CHARACTERISTIC:: ACID, BASE AND SALT

Solution SBI 2008 1

Definition of Solution Solution is a mixture of homogenous of the solute and solvent. Solute: the substance dissolved Solvent: the liquid to dissolve to solute The number of solute is relatively less than the solvent. Example: Solution of HCl(aq): the solute is HCl and the solvent is water The solution of sugar: The solute is sugar (C12H22O11) and the solvent is water. Solution SBI 2008 2

Definition of solution (Cont’d)

Colligative Properties of solution are the properties of solution which only depends on the concentration of solution. The solution concentration can be express as: 1. Molarity (M) 2. Molality (m) 3. Mole fraction (X) 4. Normality (N) 5. Percentage (%) Solution SBI 2008 3

Definition of solution (Cont’d)

Let’s check the definition one by one: W 1000 1. Molarity (M) is the amount x M= of mole of solute in 1 liter Mr V of solvent. M = molarity (mole/L) M = mole/L W = the mass of the substance The unit of M is mole/L or Mr = the molecule relative mass mmole/mL V = volume of solution in mL) As 1 mol = 1000 mmol; 1 L = 1000 mL Or we can also write as: Solution SBI 2008 4

Definition of solution (Cont’d)

Example: What is the molarity of 4 gram of NaOH in 100 mL solution? (Mr NaOH= 40) Answer: M = 4/40 x 1000/100 = 1 M (1 mole/L) Question 1: How many grams of KNO3 which has been dissolved in 5.4 L solution to get concentration of 2.5 M Solution SBI 2008 5 (Mr KNO = 101)

Definition of solution (Cont’d)

1. Molality (m) is the amount of mole of W 1000 x solute in 1000 g or M = Mr g 1 kg of solvent. m = mole/kg m = molality (mole/L) W = the mass of the substance The unit of m is mole/L Mr = the molecule relative mass g = mass of solution in gram) or mmol/mL Solution SBI 2008 6

Definition of solution (Cont’d)

Example: What is the molality of 34 gram of AgNO3 in 2.5 Kg water? (Mr AgNO3 = 170) Answer: 2.5 kg = 2500 g m = 34/170 x 1000/2500 = 0.08 m Question 2: How many grams of NaCl which has been dissolved in 2 kg solution to get concentration of 5 m (Mr NaCl = 58.5) Solution SBI 2008 7

Definition of solution (Cont’d)

4. Percentage (%) There are two types of this concentration a. Mass Percent: the percent by mass of the solute in the solution Mass percent = (mass of solute) x 100% (mass of solution) b. Volume percent: the percent by volume (mL) in every 100 mL of solution Mass volume = (mL of solute) x 100% mL of solution