King Saud University
  Help (new window)

تحميل الدليل التدريبي

أسئلة شائعة

  Tutorial 1;

1- calculate the following : 

a)The weight in grams of 1 x10 11  molecules of Nacl.

b)The number of molecules in 2.25 grams of glycine.

c)The weight in grams of  0.45 moles of glucose .

2-Calculate the Normality 0f the following solutions

a)250ml of HCL containing 18.25g of HCL.

b) 49.0g of H2SO4  in 250 ml .

3-  12.25g of H3PO4 was dissolved in water and the volume made up to 100ml calculate ;

a)The Normality of the solution.

b)The Molarity of the solution.

4- 2.0g of Nacl was dissolved in 200ml of water what is its w/v % ?

5-Calculate the v/v % of ethanol in a solution prepared by diluting 30ml of ethanol to 250ml.

6-Calculate the number of grams of Bacl2.2H2o that are needed to prepare 100ml of a 0.2 Molar solution.

7- How many ml of 0.8 M acetic acid are needed to prepare 200ml of  0.4 N acetic acid .?

8- Calculate the molarity of a 10%  w/v %   MgCL2  solution.

9- How  would you prepare 0.2L of  0.3 % MgCL2  w/v %    solution ?.

10- Concentrated HCL is 37.5% HCL by weight and has a density of 1.19 .a)calculate the molarity of the concentrated acid  b)Describe the preparation of 350ml of 0.5N HCL.



Tutorial  2: 

1- 60 ml of sucrose solution contains 0.006g of sucrose ,calculate the ppm of sucrose in the solution .

2- 200ml of air collected in Jeddah contains the following gases ;

a) 0.003 ml hydrogen sulphide.

b) 0.04 ml hydrogen cyanide .

express the concentration of each gas in ppm.

3- A solution of sulphuric acid is 4% ( w/w) ,density 1.84 g/ml . calculate ;

a) Molarity .

b) Normality.

c) Molality .

4- A solution was prepared by dissolving 8.0g of solid ammonium sulphate (mw = 132.14) in 35 ml of water , express the concentration of ammonium sulphate in terms of molality .

5- Calculate the ionic strength of the following solution ;

a) 0.5 M Na3PO4  .

b) 200 ml containing 8.0g Fe2(SO4)3   .

c) A mixture of 0.1 M Fructose ,0.5M MgCL2 and a 1.0 M NaH2PO4.

6- What is the Molarity of pure ethanol (that is how many moles are present in 1L ) The density of ethanol is  0.789g/ml ,mw=46.07 .?

 7- A solution of H2SO4 which is 64%  w/w , density 1.84 g/ml calculate ;

a) Molarity .

b) Normality .

c) Molality .

8- Describe the preparation of 2L of a 0.23M H2SO4  solution starting from a stock solution of H2SO4  ( 92%  w/w ,SG 1.84 g/ml )

9- Calculate the Molarity  of H2SO4 solution which has a molality of  6.8 molal  and  density =1.84 g/ml .  

Tutorial 3:

- How many ml are in 2500µl  ?

-The molecular weight of the amino acid alanine is 89 .How many grams are in 30mmol of alanine?

-How many µmol are dissolved in 1L of a 30µM solution?

-If the molecular weight of substance x is 212 what is the molarity of the previous solution, given that it had a concentration of 10.68 g/l ?

-The molecular weight of the amino acid alanine is 89.How many µg are in 200ml of a 0.02% (w/v) solution of alanine ?

 The molecular of glucose is 180. Express a blood glucose      concentration of 80 mg per 100 ml as a molarity? .

-The molecular weight of urea is 60.5g were dissolved in 50ml water . 10ml of this solution was added to 50ml water. What was the molarity of this final diluted solution ?

-A 0.1ml sample of a solution of compound x was added to 4.9ml water. The concentration of the resulting solution was 20M . What was the concentration of the initial solution of x and how many mol/ml were there in the final solution?

-A man drinks a cup of tea containing 2 teaspoonfuls of sugar (sucrose). What  change might you expect in the molarity of his blood glucose ?

(you may need the following information : 1 teaspoonful = 5g ; 1 mol sucrose = 1mol glucose + 1mol fructose , each with molecular weight =

180; fructose can be converted into glucose in the body ; average weight of a man = 70 kg , with 20% of this weight as extracellular fluid).

-A woman has 3g of iron in her body , of which 75% is in the form of haemoglobin .i) how much haemoglobin is that: ii) how much oxygen can it bind (in moles) and (iii) what volume of air would it deplete of oxygen? (you may need the following information –the molecular weight of haemoglobin is 68000 ; the molecule is a tetramer with four subunitseach containing one iron atom and each binding 1 molecule of oxygen . 1 mol O2  occupies  22.4 liters . Air contains  20%   O2 (v/v) . Atomic weight  Fe = 55.8)

Tutorial 4:

 1- Caculate the pH, pOH, and number of Hydrogen and Hydroxyl ions per liter in a 0.01M HCL solution.

2- Calculate the Hydrogen ion concentration (M), the Hydroxyl ion concentration,of a solution that has a pH = 2.73.

3- Calculate the Hydrogen ion concentration,Hydroxyl ion concentration,pH and pOH of the final solution obtained after 100ml of 0.2M NaOH are added to 150ml of 0.4M H2SO4.

4-The pH of a 0.1M HCL solution was found to be 1.15. Calculate the (a) activity of Hydrogen ion,and (b) activity coefficient of Hydrogen ion in this solution.

5- The activity coefficient of the Hydroxyl ion is 0.72 in a 0.1M solution of KOH . Calculate the pH and pOH of this solution.

6-Concentrated H2SO4 is 96% H2SO4 by weight and has a density of 1.84gm/ml . Calculate the volume of concentrated acid required to make a dilute H2SO4 solution of pH 3.8.

7- How many milliliters of 0.12M H2SO4 are required to neutralize exactly half of the Hydroxyl ions present in 540ml of 0.18N NaOH?

8-The weak acid ,HA ,is 2.4% dissociated in a 0.22M solution.Calculate (a)the Ka,(b)the pH of the solution,(c)the amount of 0.1N KOH required to neutralize 550ml of the  weak acid solution ? (d)the number of Hydrogen ions in 550ml of the weak acid solution.

9-The  pH of a 0.27M solution of a weak acid ,HA is 4.3. (a) What is the Hydrogen ion concentration in the solution ? (b)What is the degree of  ionization of the acid ? (c) What is the Ka?

10-The Ka of a weak acid HA, is 3x 10-4 .Calculate (a)the  Hydroxyl ion concentration in the solution and (b)the degree of dissociation of the acid in a 0.15 M solution.

11-Calculate (a)the pH of a0.05 M solution of ethanolamine ,Kb = 2.8x10-5. (b) What is the degree of ionization of the of the amine?

12- How many milliliters of 0.1M KOH are required to titrate completely 270ml of 0.4 M propionic acid?

13-What are the final Hydrogen ion concentration and pH of a solution obtained by mixing 100ml of 0.2 M KOH with 150ml of 0.1M HOAc? pKa of HOAc = 4.77.

14- What are the final Hydrogen ion concentration and pH of a solution obtained by mixing 400ml 0.2M NaOH with 150ml of 0.1M H3PO4? pKa's are 2.12, 7.21, and 12.32.


 15- How many ml  of 0.05M H2SO4 are required to neutralize 100ml of 0.1M  KOH ?  

 16- Calculate the pka ,pkb and Kb for the following weak acids

a) Acetic acid ,Ka=1.8×10 

b) Ammonium  ion Ka=5.7×10

Tutorial 5 ;

1) A weak acid HA and KOH were mixed in the following proportions

HA = 0.125 mole .

KOH = 0.025 mole .

The resulting solution was diluted to 500 ml .calculate the pH of the solution (Ka of HA = 1.77 x 10 -4)     .

2) 4.9 grams of CH3COOK is dissolved in 125 ml of 1M CH3COOH and the solution was made up to 250ml .calculate ; (pKa= 4.76)

a) The pH of the final solution .

b) The Molarity of the buffer .

3) 200ml of 0.2M NaOH was mixed with 800 ml of 0.1M  HCOOH .

Calculate the pH of the resulting solution . pKa = 3.75.

4) Starting from   1.0 M formic acid and solid sodium formate . Describe how to prepare 5L of a 0.5 M Formate buffer, pH = 4 ,                       Ka =1.78 x 10-4 .  

Tutorial 6 ;

1) Describe how you would prepare one litre 0.1M phosphate buffer ,pH = 2.0 ,given 0.1M phosphoric acid and solid  NaH2PO4.2H2O .

2) Describe how you would prepare 250ml of 0.2M phosphate buffer , pH =12 ,given solid Na2HPO4. 2H2O . and Na3PO4.H2O.

(pKa1 = 2.12 , pKa2 = 7.21 , pKa3 = 12.32 ).

3) Calculate the volume of 0.1 KOH required to titrate completely (a)450ml of alanine hydrochloride, (b) 400ml of 0.15M monosodium glutamate, and (c) 400ml of 0.15M isoelectric glutamic acid. 

  4) The pH of 250 ml of 0.2M aspartic acid is 0.2 . Sketch the titration curve obtained by titrating the aspartic acid solution with 0.5M KOH show clearly how you obtain the values used to plot the curve.

(pKa1  = 2.0 , pKa 2 = 3.8 , pKa3 =9.8 )








King   Saud University. All rights reserved, 2007 | Disclaimer | CiteSeerx