CHM191

1. The technique of separation employed to purify an organic solid that may be contaminated by impurities is called __________

2. An acid HA has a pka of 4.5. What is the concentration of $$H_{3}^{+} $$ in 0.110M solution of the acid ? ________

3. When two or more elements combine chemically in fixed proportion by mass, is formed _________

4. 3.47g sodium carbonate was dissolved in a 250millilitre standard flask. What is the concentration of the resulting solution

5. From the equation $$2HCl + Na_{2}CO_{3} → 2NaCl + CO_{2} + H_{2}O$$, given that 2 moles of HCl reacted with 1 mole of $$Na_{2}CO_{3}$$. What was the concentration of the acid?

6. $$The label on a stock bottle of an acid reads: 56% by mass and 1.25 specific gravity. If the molar mass of the acid is 56, find the moles per dm^{3}$$

7. The number of protons or electrons in the atom of an element is equal to the _________ of the element

8. The smallest unit of a compound that manifest all the chemical properties of the compound is called ________

9. The concentration of the pure HCl used is 11.7 molar. If $$20.0cm^{3}$$ V1 of 1 1.7 molar of $$C_{1}$$ of HCl is diluted to 250cm^{3} of V_{2}, then the new concentration C_{2} will be ______

10. A standard solution of a substance can be prepared if the substance can be obtained in ______ state.

11. The base unit of a measured liquid called volume is __________

12. An acid HA has a pka of 4.5, what is the Ka value? _________

13. A standard solution is a _________

14. The reagent that will not make any significant contribution to the theoretical yield is _________

15. A mixture in which the components are evenly distributed and the composition is uniform throughout the mixture is called _________ mixture.

16. Calculate the [OH^{-}] of an aqueous solution of Ph=11 ____________

17. When two or more elements combine chemically in fixed proportion by mass, _________ is formed

18. The formular obtained by multiplying the number of each atom in the empirical formular by n is called ____________

19. The molar mass of $$Na_{2}CO_{3}$$ ________

20. The actual yield of product (in g or moles) expressed as a percentage of the theoretical yield (in g or moles ) is called ____________

21. In a standardization titration involving hydrochloric acid and sodium carbonate, a student recorded the following results for the volume of hydrochloric acid used against 10.00mL of the sodium carbonate solution : 15.60; 14.50; 14.70 aqnd 14.20. If the concentration of the $$Na_{2}CO_{3}$$ standard solution is 0.75moldm^-3, calculate the concentration of the HCl solution.

22. The reagent with a ________ stoichiometric amount (in moles) that limits the amount of desired product (in moles ) formed is called

23. There are _____ different techniques for  determination of an unknown sample in titrimetric analysis.

24. The separation technique employed to separate mixtures of two or more liquids with slightly different boiling points is called __________

25. A high percentage yield implies that ___________

26. The technique employed for the separation of colours is called _________

A substance with a pH value of >7< 10 is a ______________

28. A separation technique that is used to isolate a desired solid from a solid -liquid mixture or for freeing a desired liquid of solid impurities is called _________

29. Convert 2 moles of NaOH to grams of NaOH. Answer is ________

30. The solution whose concentration is known is called ___________

31. A compound in grams is converted to moles by diving by ________

32. The types of mixtures are _________, _________ mixture.

33. There are _______ types of titrimetric analysis.

34. When propane reacts with oxygen, the products are ______  and ________

35. An undergraduate weighed out 20grams of sodium hydroxide pellets. If Na =23, O = 16 andH = 1, What is the mole of this sodium hydroxide. ___________

36. Convert 500g of $$ Na_{2}CO_{3}$$ to moles _______

37. Calculate the $$[H^{+}] $$of an aqueous solution wity $$[OH^{-}] of 1× 10^{-10}M$$. What is the pH of the solution? Is the solution acidic or basic? ________

38. In this equation $$2NaHCO_{3} → Na_{2}CO_{3} + ? + CO_{3}$$, the compound represented by ? is __________

39. The base unit of a measured or weighed solid material in chemistry is ________

40. Dissolution 0f sodium chloride in water results in __________ type of mixture

41. In titration, the experimentally determined stoichiometric point of the titration is referred to as _______

42. The number of gramequivalent weight of solute in one cubic decimeter of solution is ______

43. The separation technique employed to purify an organic liquid or to separate mixtures of liquids of different volatilities or boiling points is called __________

44. $$The label on a stock bottle of an acid reads: 56% by mass and 1.25 specific gravity. If the molar mass of the acid is 56, find the volume of this acid that is required to prepare 250cm^{3} of 1.0 molar concentration of the acid$$.

45. The process by which traces of water is removed by treating the liquid with suitable drying agents is called _________

46. The procedure by which a solution of known concentration is Added to another solution until the chemical reaction between the two ssolutes is complete is ______.

47. The condensate collected during the vaporization of liquid is called _________

48. If actual yield of an ester is 32.7g and theoretical yield is 35.1g .What is the percentage yield of the ester?

49. An apparatus that can be used to remove traces of water from a substance is ________

50. The residue of a chemical reaction is allowed to cool in a ________