Question 2 :
The sum of mass of all the atoms in a molecule is known as :

Question 4 :
The molecular mass of $(NH_4)_2CO_3$ is :Given atomic mass of H = 1, O = 16, C = 12, N = 14.<br/>

Question 8 :
One mole is equal to number of atoms as contained in:

Question 10 :
A compound contains atoms of three elements A, B and C. If the oxidation number of A is +2, B is +5 and that of C is -2, the possible formula of the compound is&#160;

Question 11 :
Assertion: 23 g of sodium has $6.022 \times 10^{23}$ atoms sodium. Reason: Number of atoms in the given mass of sodium cannot be determined

Question 12 :
Assertion: 1 g atom of $O_2$ and 1 g atom of $O_3$ have equal number of molecules. Reason: Mass of 1 mol atom is equal to its gram atomic mass.

Question 14 :
The relative formula mass, $M_{r}$, of calcium carbonate, $CaCO_{3}$, is $100$. What is the mass of carbon present in $100\ g$ of calcium carbonate?

Question 15 :
The atomicity of a species is $x$ and its atomic weight&#160;is $y$. The molecular weight of the species is:<br/>

Question 16 :
The number of molecules present in $4.4$ g of $CO_{2}$&#160;gas is:<br/>

Question 18 :
How many moles of calcium carbonate $(CaCO_3)$ are present in 20 g of the substance?&#160;($Ca = 40,\ C = 12,\ O = 16$)

Question 19 :
Two elements $A$ and $B$ contain $13$ and $8$ protons respectively. If the number of neutrons in them happen to be $14$ and $8$ respectively; the formula unit mass for the compound between $A$ and $B$ unit would be:

Question 20 :
2 moles of chlorine atoms are present in_____g of chlorine gas.

Question 21 :
What is the mass in grams of 3 moles of $N_2$?

Question 22 :
The number of atoms in 0.1 mol of a triatomic&#160;gas is:

Question 23 :
An atom of one element A has three electrons in its outermost shell, and that of B has six electrons in the outermost orbit. The formula of the compound formed by these two will be :

Question 24 :
The valency of a metallic element is $2$ and its equivalent weight $32$. If the atomic weight of chlorine $35.5$. The molecular weight of the chloride of that metal is :

Question 25 :
Arrange the following in increasing order of number of molecules<br>I. 0.5 mol of ${H}_{2}$ II. 4.0 g of ${H}_{2}$<br>III. 18 g of ${H}_{2}O$ IV. 2.2 g of $C{O}_{2}$

Question 26 :
3 volumes of hydrogen are required to combine with one volume of nitrogen to form 2 volumes of ammonia. When 1 mole of hydrogen is allowed to react with the mole of nitrogen, the two gases?

Question 29 :
Assertion: Pure water obtained from different sources such as river, well, spring, sea etc. always contain hydrogen and oxygen combined in the ratio $1 : 8$ by mass. Reason: A chemical compound always contains elements combined together in same proportion by mass, it was discovered by French chemist, Joseph Proust (1799).