Some Basic Concepts of Chemistry Mock Test – Class 11 Chemistry

1. A mixture of sand and water is shaken and then allowed to stand. The sand gradually settles at the bottom. This observation supports the idea that the sample is:

2. A naturally occurring sample of chlorine contains and . The average atomic mass is:

3. A jar contains iron filings and sulphur powder mixed together without heating. The sample is best described as:

4. Consider these statements about solution stoichiometry:
I. Molarity can convert solution volume into moles of solute.
II. A balanced equation converts moles of one reacting substance into moles of another.
III. Mass of product can be found from product moles using molar mass.

5. Study the following limiting-reagent records for .

The case with the wrong conclusion is:

6. A mixture of salt and sand can contain salt in one sample and salt in another sample. This does not obey the fixed-ratio behaviour of compounds because:

7. A notebook gives four measured values and claimed significant figures.

The row that needs correction is:

8. Assertion: A set of readings can be highly precise but poorly accurate.
Reason: Repeated readings may be close together even when an instrument has a constant calibration error.

9. A compound has empirical formula . Its vapour-density-based molar mass is found to be . Using and , the molecular formula is:

10. A solution contains of in of solution. If molar mass of , what is its molarity?

11. A sample contains of . The total number of atoms present in the sample is:

12. After heating iron and sulphur strongly, a new black substance is formed and the iron cannot be separated by a magnet in the same way. The strongest conclusion is:

13. A sample is represented as . The best classification is:

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

15. A solution is prepared by dissolving of in water and making the volume . If of this solution is taken, how many moles of does the aliquot contain? Use .

16. A lab record states:

The pair with equal masses is:

17. Use the arrangement described below: a solution pathway has three boxes.
Box P: mass of known substance
Box Q: moles of known substance
Box R: moles of required substance
Box S: mass of required substance
For a mass-to-mass stoichiometric calculation, the correct pathway is:

18. In a precipitation reaction, of is mixed with excess . For , the mass of formed is closest to: .

19. A pure substance is broken down by a chemical method into two simpler substances. The original substance is best described as:

20. Match the chemistry focus in Column I with the most suitable description in Column II.

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

22. A candle is burning on a table. Wax near the flame melts first, and then wax vapour burns in air. The best interpretation is:

23. The prefix is used in and . It represents:

24. Read the short record below.

The property that gives chemical information is:

25. A aqueous solution of a non-electrolyte contains solute in water. The mole fraction of solute is closest to: use .

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

27. A sealed bottle contains sugar crystals, and a spoon contains table salt. Both are examples used in chemistry because:

28. A value is changed from to . What happens to the number of significant figures?

29. A solution contains of lead ions in of a dilute aqueous solution. Taking , the concentration of lead ions is:

30. A chemistry record gives a liquid volume as , a sample mass as , and an amount as . The best interpretation is:

31. Density is obtained by dividing mass by volume. If mass is measured in and volume in , the unit of density becomes:

32. A food label mentions added minerals, a clinic uses an antiseptic, and a factory produces plastic containers. The shared reason these are chemistry-related is:

33. A proposed molecular formula calculation gives empirical formula , empirical formula mass , and experimental molar mass . The best interpretation is:

34. For , of and of are mixed. The limiting reagent is:

35. Avogadro's number is commonly written as . The exponent mainly shows that the number is:

36. A solution contains of in of solution. Its molarity is:

37. A chemical quantity is written as . The unit most likely belongs to:

38. A mass is reported as . The final zero is significant mainly because:

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

40. The volume relation is useful because:

41. Use the table below and identify the row with the mismatched prefix factor.

42. Consider these statements about physical and chemical changes:
I. A physical change does not produce a new substance.
II. A chemical change produces one or more new substances.
III. Every reversible change must be chemical.

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 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:

45. In the measured value , the zeros are significant because they are:

46. A data sheet lists , , , , , , and . The common feature of these symbols is that they are:

47. In agriculture, fertilizers are useful chemical products because they mainly:

48. A sample of at contains how many hydrogen atoms?

49. Carbon and oxygen form and . For the same mass of carbon, the masses of oxygen that combine are in the ratio:

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