Unit 1: Basic Concepts Chemistry covers fundamental ideas such as atomic structure, chemical laws, mole concept, and stoichiometry, providing a strong foundation for students to understand advanced chemistry topics and excel in exams.
1. Isotopes differ in
a. properties which depend on mass
b. arrangement of electrons in orbitals
c. chemical properties
d. the extent to which they may be effected in electromagnetic field
2. Select the most suitable answer from the given ones in each question
a. Isotopes with even atomic masses are comparatively abundant
b. Isotopes with odd atomic masses are comparatively abundant
c. Isotopes with even atomic masses and even atomic numbers are comparatively abundant
d. Isotopes with odd atomic masses and odd atomic numbers are comparatively abundant
3. Many elements have fractional atomic masses. This is because
a. the mass of the atom is itself fractional
b. atomic masses are average masses of isobars
c. atomic masses are average masses of isotopes
d. atomic masses are average masses of isotopes proportional to their relative abundance.
4. The mass of one mole of electron is
a. 1.008mg
b. 0.55mg
c. 0.184mg
d. 1.673mg
5. 27g of Al will react completely with how much mass of O2 to produce Al2O3
a. 8g of oxygen
b. 16g of oxygen
c. 32g of oxygen
d. 24g of oxygen
6. The number of moles of CO2 which contain 8g of oxygen
a. 0.25
b. 0.50
c. 1.0
d. 1.50
7. The largest number of molecules are present in
a. 3.6g of H2O
b. 4.8g of C2H5OH
c. 2.8g of CO
d. 5.4g of N2O5
8. One mole of SO2 contains
a. 6.02*1023 atoms of oxygen
b. 18.1*1023 molecules of SO2
c.6.02*1023 atoms of sulphur
d. 4g atoms of SO2
9. Volume occupied by 1.4g of N2 at S.T.P is
a. 2.24dm3
b. 22.4dm3
c. 1.12dm3
d. 112cm3
10. A limiting reactant is the one which
a. is taken in lesser quantity in grams as compared to other reactants
b. is taken in lesser quantity in volume as compared to other reactants
c. gives the maximum amount of product which is required
d. gives the minimum amount of product under consderation