Is from strong electrolytes

A- Benzene B- H2O C- HCl (g) D- HCl (aq)

4- The measuring unit of molality (m) is ……

A- mol/kg B- mol/L C- g/L D- g/eq.L

2- What's meant by

1- Solubility

2- Saturated solution

3- Boiling point (in terms of vapour pressure)

3- Solve the following problems

1- Calculate the percent concentration of sucrose in a solution containing 10g of sucrose and 240g of water

2- If we add 50 ml of water to 25 ml of ethanol (ethyl alcohol) calculate the percent concentration of ethanol in the solution.

3- Find the molar concentration of a sodium hydroxide solution of volume 200 ml containing 20g of sodium hydroxide (NaOH) (Na=23, O=16, H=1)

4- if 53g of sodium carbonate (Na2CO3) dissolved in 400g of water, calculate the molality of the solution (Na=23, O=16, C=12, H=1)

Determine the type of colloidal systems of the following

1- Mayonnaise

2- Dust in air

Choose the correct answer

1- liquid in gas

2- 104.5

3- HCl (aq)

4- mol/kg

2- What's meant by: page (15)

Solve the following problems

1- percent concentration = 100 x (mass of solute / mass of solution) =

100 x (10/240) = 100x 0.24 = 24%

2- The volume of the solution = the volume of solute + the volume of solvent =

25 + 50 = 75 ml

The percent concentration of ethanol = 100 x (25/75) = 100 x 0.333 = 33.3%

3- The molar mass of sodium hydroxide = 23+16+1 = 40g

The no. of moles in 20g of sodium hydroxide = 20/40 = 0.5 mole

200 ml = 0.2 L

The molar concentration = (the no. of moles of solute / volume of solvent)

= 0.5/ 0.2 = 5/2 = 2.5 mol/L

4- The molar mass of sodium carbonate = 23+23+12+16+16+16= 106g

The no. of moles in 53g of sodium carbonate = 53/106 = 0.5 mole

400g = 0.4kg

The molality of the solution = the no. of moles of solute / the mass of solvent =

0.5/0.4 = 1.25 mol/kg

Determine the type of colloidal systems

1- Mayonnaise:-

Medium of dispersion: Liquid

Dispersed substance: Liquid

2- Dust in air

Medium of dispersion: Gas

Dispersed substance: Solid

Lesson (2)

Acids and Bases

Acids and bases play an important role in life. Acids are used in the industry of fertilizers, explosives, medicines, plastic, car motors, computers…etc. Bases are used in the industry of soap, detergents, medicines, dyes…etc

The following table shows some chemical and natural products and the acids or bases forming them

Acids or bases forming it	Product
Ascorbic acid – Citric acid	Sour fruits (lemon, orange, tomato)
Lactic acid	Dairy products (yoghurt, milk, cheese)
Carbonic acid – Phosphoric acid	Fizzy drinks
Sodium hydroxide	Soap
Hydrated sodium carbonate	Washing soda
Sodium bicarbonate	Baking soda

Acid: ACompound with sour taste which turn the colour of blue litmus paper into red

- It reacts with metals forming hydrogen

- It reacts with carbonate or bicarbonate salts forming carbon dioxide gas

- It reacts with alkalis (bases) forming salt and water

Base (Alkali): A compound with bitter taste and soap texture which turns the colour of red litmus paper into blue, it reacts with acids forming salt and water

Дата добавления: 2015-10-23