CHM191

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

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

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

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

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

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

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

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

9. When a substance is not available in a pure form, its solution can be standardized by ___________

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

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

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

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

14. 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.

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

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

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

18. 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 ______

19. 3.47g sodium carbonate was dissolved in a 250millilitre standard flask. What is the concentration of the resulting solution

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

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

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

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

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

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

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

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

28. 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 ______.

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

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

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

32. A standard solution is a _________

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

34. The solution whose concentration is known is called ___________

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

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

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

38. 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 _________

39. 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?

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

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

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

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

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

45. 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? ________

46. A high percentage yield implies that ___________

47. There are _______ types of titrimetric analysis.

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

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

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