Question
Question: In \[6.72\,g\] of\[{N_2}{H_4}\], how many? A.How many \[{N_2}{H_4}\] molecules are present? B.Ho...
In 6.72g ofN2H4, how many?
A.How many N2H4 molecules are present?
B.How many N atoms are present?
C.How many protons are present?
Solution
Hydrazine is an inorganic compound having the chemical formula of N2H4. A mole is defined as 6.02214076×1023 of a chemical unit in the terms of ions, atoms, molecules, etc.
1mole=6.022×1023atoms
Therefore, for 1 atom will be;
1atom=6.022×10231moles
So, the answer will be;
1atom=1.66×10−24moles
Complete step-by-step answer: First, we need to find how many N2H4 molecules are present?
Let’s observe the given values;
Here, we have {N_2}{H_4}$$$$ = \,6.72\,g
To calculate the number of moles;
Let’s use the equation;
Number of moles, n=molecularmassmass
The given mass of hydrazine (N2H4)=6.72g
The molecular mass of hydrazine (N2H4);
=14×2+1×4
=32 g/mol
Substitute the values in above equation,
n=32g/mol6.72g
So, the number of moles will be;
n=0.21moles
We have to multiply with the Avogadro’s number to get the (N2H4) molecules.
Now, let’s calculate the number of molecules present in 6.72g of (N2H4)
=0.21×6.023×1023
=1.2648×1023 molecules
So, the answer obtained will be, 1.2648×1023 molecules are present in 6.72g of (N2H4) .
Secondly, we need to find that how many N atoms are present;
So, for that we must know that there are two atoms of nitrogen participating for every molecule of hydrazine;
=1.2648×1023×2
=2.52×1023 atoms of nitrogen.
Thirdly, we need to find how many protons are present;
We know that the atomic number will be equal to the number of electrons and the electrons are equal to the number of protons. So, we have 7 protons of nitrogen because the nitrogen’s atomic number is 7 and 1 protons of hydrogen because the atomic number is 1 .
But we need to calculate the atoms of hydrogen so that the calculation can be easy;
So, for that we must know that there are four atoms of hydrogen participating for every molecule of hydrazine;
=1.2648×1023×4
=5.05×1023 atoms of hydrogen.
Now, let’s calculate the number of protons;
So, the total number of protons will be;
=7×2.52×1023+1×5.05×1023
=22.69×1023 protons are present.
Note: A mole is a unit measurement for the amount of substance in the international system of units i.e., SI unit. A mole of a particle or a mole of a substance is defined as 6.02214076×1023 of a chemical unit, that can be ions, atoms, molecules, etc. Originally it was defined as the number of atoms in 12 g of carbon-12.