Q.3 Explain : A) The need of the term average atomic mass
D) Formula mass with an example
E) Molar volume of gas.
C) Mole concept
B) Molar mass
Q.3 Explain :
Answers
Answer:
a) There are millions of atom in a single page of a book. It's almost impossible to measure each and every one by one and count it. So to make the calculations easier , we take Average Atomic mass.
d) (do you mean mass percentage ?)
Mass Percentage = Mass of the required Solution / Total Mass of Solution X 100
Example : if 40g of NaCl mixed with 120g of Water. Then, Required solution = 40g
Total Mass = 40+120= 160g
Mass Percentage of NaCl = 40/160 X 100 = 25%
e) Molar Volume is volume occupied by one mole of a gas at Standard temperature (0 degree or 273 kelvin) and pressure (1 ATM). The Molar Volume of a gas at STM (Standard time and pressure ) is 22.4 dm^3.
c) Similar to first question. It's very difficult to county atom individually and that's why we take one mole or 6.022 x 10^23 atoms for simpler calculations. Difference of few atoms have negledgible effect on macroscopic or large level and can be ignored .
b) Molar mass = Mass of 6.022 x 10^23 atoms of the given element. Oxygen's Molar mass is 16g which means that there are 6.022 x 10^23 oxygen particles .