(i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons. * -------------------------------------------------
Answer
(i) Mass of one electron = 9.10939 × 10–31 kg
Number of electrons that weigh 9.10939 × 10–31 kg = 1
Number of electrons that will weigh 1 g = (1 × 10–3 kg)
= 0.1098 × 10–3 + 31
= 0.1098 × 1028
= 1.098 × 1027
(ii) Mass of one electron = 9.10939 × 10–31 kg
Mass of one mole of electron = (6.022 × 1023) × (9.10939 ×10–31 kg)
= 5.48 × 10–7 kg
Charge on one electron = 1.6022 × 10–19 coulomb
Charge on one mole of electron = (1.6022 × 10–19 C) (6.022 × 1023)
= 9.65 × 104 C
Question 2.2:
(i) Calculate the total number of …show more content…
have been used to be bombarded by the α-particles. If the thin foil of light atoms like aluminium etc. is used, what difference would be observed from the above results? * -------------------------------------------------
Answer
A thin foil of lighter atoms will not give the same results as given with the foil of heavier atoms.
Lighter atoms would be able to carry very little positive charge. Hence, they will not cause enough deflection of α-particles (positively charged).
Question 2.41:
Symbols can be written, whereas symbols are not acceptable. Answer briefly. * -------------------------------------------------
Answer
The general convention of representing an element along with its atomic mass (A) and atomic number (Z) is
Hence,is acceptable butis not acceptable. can be written but cannot be written because the atomic number of an element is constant, but the atomic mass of an element depends upon the relative abundance of its isotopes. Hence, it is necessary to mention the atomic mass of an element
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