Some Basic Concepts of Chemistry Mock Test – Class 11 Chemistry

1. A silver spoon slowly turns black when exposed to air containing traces of sulphur compounds. The change is best classified as:

2. In the the mixture , of and of are used. What amount of can form?

3. A student tries to prove the law of multiple proportions using two samples of pure with different masses. The attempt is weak because:

4. To prepare of solution from a stock solution, the volume of stock solution required is:

5. Use the arrangement described below: four cards describe properties of a substance.
Card P: melts at
Card Q: dissolves in water
Card R: reacts with silver nitrate solution to form a white precipitate
Card S: has white crystalline appearance
The card that most clearly gives a chemical property is:

6. Match each term in Column I with the best description in Column II.

7. A substance has molecular formula . Using atomic masses , , and , its molar mass is:

8. Diluting a solution from to without adding more solute changes the solution mainly because:

9. The formula represents a compound rather than a mixture because:

10. Convert to , using .

11. A student records with a decimal point after the zeros. The decimal point indicates that:

12. For , of zinc reacts with excess hydrochloric acid. The amount of formed is:

13. A compound has empirical formula and molar mass . The molecular formula is:

14. A solution of is mixed with of . For , the concentration of ions in the final solution after precipitation is:

15. A solution contains total chloride ions after complete dissociation of . The concentration of is:

16. The concentration unit is commonly interpreted for very dilute aqueous solutions as:

17. A chemistry calculation uses the unit for molar mass. This unit is not an base unit because:

18. A reaction is carried out in an open beaker, and bubbles escape into the air. The mass measured in the beaker after the reaction is lower than before. The best explanation is:

19. A reaction is represented by . If of A reacts with excess B, the amount of C formed is:

20. Two balances are used for the same standard mass.

The best comparison is:

21. A value must be rounded to significant figures. The correct rounded value is:

22. A mass value written as for oxygen refers to:

23. The percentage of oxygen in , using and , is closest to:

24. In , of reacts with of . What amount of can form?

25. A shiny grey solid conducts electricity, has density , and slowly rusts in moist air. Which entry is a chemical property?

26. A volume is reported as . Using , the same volume in is:

27. For the gaseous reaction , all gases are measured at the same and . If of reacts completely, the volume of required is:

28. The most useful difference between a compound and a mixture is that a compound:

29. A student writes the unit of molar mass as . The best correction is:

30. A note says, "Density and melting point are physical properties, but acidity and combustibility are chemical properties." The best reason for accepting this note is:

31. A sample of is mixed with of . Assuming complete precipitation of and additive volumes, the final concentration of unprecipitated ions is:

32. A student says, "The reactant with the smaller mass is always the limiting reagent." The best correction is:

33. A formula contains parentheses: . The number of oxygen and hydrogen atoms in one formula unit is:

34. A cold metal plate is held above steam, and droplets of water appear on the plate. The change occurring at the surface of the plate is:

35. The formula mass of , using , , and , is:

36. Use the table below for complete dissociation in water.

The row that needs correction is:

37. A portion of is diluted to . After complete dissociation, the amount of ions in the diluted solution is:

38. A student treats as if it supplies only total ions. The best correction is:

39. A measured value of a mass is , while the accepted value is . The percentage error is:

40. Consider the following statements:
I. An element contains only one type of atom.
II. A compound has elements chemically combined in fixed proportion.
III. A mixture always has a fixed chemical formula.

41. The sum is to be reported using the correct significant-figure rule for addition. The best reported value is:

42. Which statement best represents a limitation of Dalton's atomic theory from a modern viewpoint?

43. The graph described below is drawn for an ideal gas at .

The slope of the graph represents:

44. A solid block of iron keeps its own shape on a table, while the same volume of water takes the shape of a beaker. This difference mainly occurs because:

45. Consider the statements below:
I. Coefficients in a balanced equation give mole ratios.
II. For gases at the same and , coefficients can also give reacting volume ratios.
III. Coefficients should be used as direct gram ratios without molar masses.

46. The most useful role of laws of chemical combination is that they:

47. A classification record for four samples is shown below.

The best combined classification is:

48. A sample of a compound gives of X atoms and of Y atoms. The empirical formula is:

49. A bottle label says . The most suitable interpretation is:

50. Gay-Lussac's law of gaseous volumes should not be used directly for liquid water in the reaction because: