21. Empirical formula of chloroform is____________________?

A. CH2 C12
B. CH3C1
C. CC14
D. CHCL3

22. Molecular mass of water (18g) means__________________?

A. 1-mole molecules of water
B. 1-gram molecule of water
C. 3-gram atoms
D. all

23. Which of the following is not a macromolecule ?

a. sand
B. hemoglobin
C. diamond
D. maltose

24. Isotopes of the same elements has__________________?

A. different number of protons
B. same number of neutrons
C. different number of neutrons
D. same mass number (nucleon number)

25. When cat ionic molecular ions are allowed to pass through strong magnetic field in mass spectrometer which of the following ions is fallen__________________?

A. lighter
B. intermediate
C. heavier
D. are collected at same time

26. For which of the following compounds the term empirical formula cannot be applied ?

A.Na Cl
B. H2O
C. CCI4
D. It can be applied to all mentioned above

27. The properties of an element mostly corresponds to that isotope which has greater_________________?

A. Mass number
B. Atomic mass
C. Relative abundance
D. all of the above

28. How many isotopes have odd atomic number ?

A. 154
B. 280
C. 86
D. 300

29. Percentage of calcium in calcium carbonate is___________________?

A. 80%
B. 30%
C. 40%
D. 20%

30. Mostly elements have fractional atomic masses because of______________________?

A. mass of an atom itself is in fraction
B. atomic masses are average masses of isobars
C. atomic masses are average masses of isotopes proportional to their relative abundance
D. atomic masses are average masses of isotopes

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