THE MOLE

THE MOLE CONCEPT
1. 25CM3 of 0.1M sodium carbonate solution neutralized a solution containing 2.5g of sulphuric acid in 250cm3 of solution
a) Calculate the molarity of sulphuric acid and the volume of the acid used.

b) Write the equation for the reaction from this information.

2. 25.0cm3 of sodium hydroxide solution containing 1.0g of the alkali in 250cm3 of solution required 30.0cm3 of nitric acid for complete neutralization. Calculate the;
a) The molarity of the sodium hydroxide solution.

b) The molarity of the acid

3. A pupil analysed a commercial vinegar solution by titration and found that 24.5cm3 of 0.0981M sodium hydroxide solution was required for the titration of 1cm3 of vinegar. Calculate the molarity of ethanoic acid in vinegar. [Na = 23, H = 1, O = 16, N =14 ]

4. In a compound of magnesium and nitrogen, 54g of magnesium combines with 21g of nitrogen. Determine the empirical formula of the compound.







5. What mass of sodium oxide, Na2O could be formed from 3.45g of sodium. [ O = 16,Na = 23 ]

6. An evacuated flask has a mass of 90.050g. When filled with gas X at S.T.P. the flask weighs 90.121g. If the volume of the flask was 22.2cm3. Calculate the RMM of gas X and suggest its identity.

7. A concentrated solution of ammonia contains 30% of ammonia and has a density of 0.88gcm3. Calculate the molarity of ammonia solution.



8. 20 cm3 of 0.27M sodium hydroxide solution is added to 18.2 cm3 of 0.75M hydrochloric acid. To the solution is then added excess magnesium, what volume of hydrogen gas measured at S.T.P. evolved?


9. A metal hydroxide has the formula M (OH) 2. An aqueous solution of this hydroxide has a concentration of 6.16gl-1. 30cm3 of this solution requires 24cm3 of acid solution containing 5.67gl-1 of nitric acid for complete neutralization. Calculate;
a) The molarity of the metal hydroxide.

b) The relative atomic mass of the metal M


10. An aqueous solution of an acid contains 3.14g of XCOOH in 200cm3. 25cm3 of this acid solution are neutralized with 21.5cm3 of 0.207M solution of sodium hydroxide. Calculate the;
i) Formula mass of the acid.


ii) Relative mass of X in the acid.




11. 84cm3 of hydrogen chloride gas, measured at standard temperature and pressure is dissolved in water and titrated with 0.15M sodium hydroxide. What volume of sodium hydroxide solution is required for complete neutralization? What is the number of moles of hydrogen chloride.aka





12. 15cm3 of a solution containing 2.88gd-3 of an alkali solution XOH completely reacts with 20cm3 of 0.045M sulpuric acid. Calculate the molarity and R.A.M. of X present in the alkali.


13. 25.0 cm3 of an alkali MOH completely reacted with 20.0cm3 of nitric acid. The acid concentration was 6.3gdm-3 and that of the alkali was 3.2gdm-3. Calculate the molar mass of the alkali and hence the RAM of M.