Question
Question: How many grams of Ne are in \( 1.44 \times {10^{24}} \) atoms of Ne?...
How many grams of Ne are in 1.44×1024 atoms of Ne?
Solution
Hint : The molar mass in g/mol of an element is numerically equal to the element’s atomic mass in amu . The atomic mass of Ne is 20.18 amu . The number of particles in one mole of a substance is 6.022×1023 (Avogadro’s number).
No of moles = 6.022×1023 atoms/molNo of atoms
Mass of substance = No of moles of substance × Molar mass
Complete Step By Step Answer:
Here the number of atoms of Ne in a particular sample are given. And we are asked to find the mass of that sample in grams. We know that the mass of 1 mole of any substance is its molar mass. And the molar mass of an element is equal to its atomic mass. So, the molar mass of Ne is 20.18 g/mol .
Also, we know that there are 6.022×1023 atoms/mol in 1 mole of any substance. So, we will first use this to find the number of moles of Ne in the given sample then multiply it with the molar mass of Ne to get the mass of the sample in grams.
We know that, No of moles = 6.022×1023 atoms/molNo of atoms
⇒No of moles of Ne = 6.022×1023 atoms/mol1.44×1024 atoms
⇒No of moles of Ne = 2.391 moles
So, there are 2.391 moles of Ne in the given sample.
Now, we will use the relation between the number of moles and mass of a substance.
We know that, Mass of substance = No of moles of substance × Molar mass
⇒Mass of Ne = 2.391 mol ×20.18 g/mol
⇒Mass of Ne = 48.25 g
So, the mass of Ne in the sample is 48.25 g .
Hence, the mass of 1.44×1024 atoms of Ne is 48.25 g .
Note :
It is important to know the atomic mass of elements to solve questions of these types. Sometimes the atomic mass is given in the question. But it is better to remember it. A simple rule is to double the atomic number to get the atomic mass of the first twenty elements. But it does not always work.