Some Basic Concepts of Chemistry Mock Test – Class 11 Chemistry

1. A statement says, "The unit of mass is , because chemists commonly use grams." The best correction is:

2. Two samples are compared at : Sample P contains of , and Sample Q contains of . The best comparison is:

3. A law statement says: "When two elements form more than one compound, the different masses of one element that combine with a fixed mass of the other are in small whole-number ratios." This statement is:

4. A data table for a compound made of elements X and Y is shown below.

The sample that is not consistent with the same compound is:

5. The unit is best connected with:

6. A gas in a syringe can be compressed noticeably when the nozzle is closed, but water in the same syringe resists compression strongly. The best particle-level explanation is:

7. For a compound with formula , using atomic masses , , and , the molecular mass is:

8. Molarity of a solution is defined as:

9. A solution is by mass in sodium chloride. The mass of sodium chloride present is:

10. A beaker contains of solution. The unit is most directly related to:

11. 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:

12. What volume of is required to neutralise of in ?

13. A sample of is diluted to . After dilution, the concentration of ions is:

14. Consider the statements below:
I. Equal volumes of gases at the same and contain equal numbers of molecules.
II. Equal volumes of gases at the same and always have equal masses.
III. Avogadro's law helps relate gas-volume ratios to molecular ratios.

15. Elements A and B form two compounds. In compound P, of A combines with of B. In compound Q, of A combines with of B. The ratio of B masses for of A is:

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

17. Assertion: Dissolving common salt in water is usually treated as a physical change.
Reason: The salt can be recovered by evaporating water, and no new substance is formed in the ordinary process.

18. A solution is prepared by mixing of and of . Assuming volumes are additive and both salts dissociate completely, the final concentration of is:

19. A sample of is titrated with . For , what volume of is required for complete reaction?

20. A measuring cylinder has markings at every . A liquid level is recorded as . The most reasonable uncertainty idea is that:

21. In a measurement, accuracy mainly means:

22. A graph is described below.

The slope of this graph represents:

23. In , of reacts with of . If , , and , the theoretical mass of water formed is:

24. A number is written as . Its standard scientific notation is:

25. An element has two isotopes with masses and , present in equal abundance. Its average atomic mass is:

26. Study the classification table below.

The correct classification is:

27. The phrase "chemistry as knowledge" is different from "chemicals as substances" because:

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

29. A row in a notebook says, "A solution is always a mixture, but every mixture is not a solution." The best interpretation is:

30. In a laboratory notebook, the entry most likely records:

31. A learner writes that chemistry is mainly useful because it connects substances with measurable quantities. The strongest reason supporting this idea is:

32. A mixture differs from a pure substance mainly because a mixture:

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

34. Consider the statements below:
I. All non-zero digits are significant.
II. Zeros between non-zero digits are significant.
III. Leading zeros before the first non-zero digit are significant.

35. A table shows complete dissociation of four salts.

The row that needs correction is:

36. The base unit for amount of substance is:

37. A sample contains of water mixed with of salt. Another sample contains of water mixed with of salt. These two samples mainly show:

38. A compound contains carbon, hydrogen, and oxygen by mass. The empirical formula is:

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

40. A sample of is diluted to . The final concentration is:

41. A notebook table is shown below.

The row that needs correction is:

42. A graph is described below.

The slope of the graph is:

43. A balance always shows even when nothing is placed on the pan. Masses measured without correcting this zero error are likely to have:

44. A solution is by mass in and has mass . If molar mass of , the amount of present is closest to:

45. A solution is made by dissolving of salt in of water. The mass percentage of salt is:

46. Iron filings and sulphur powder are mixed in a dish without heating. A magnet can still attract the iron filings from the mixture. This shows that the sample is:

47. A solution contains of . Its molarity is:

48. In a closed vessel, of magnesium reacts completely with oxygen to form of magnesium oxide. What mass of oxygen has combined with magnesium?

49. A student mixes of with of . For , the amount of formed is:

50. The statement "all chemicals are dangerous" is scientifically weak because: