Question

How many grams of silicon is present in $\;35$ gram atom of silicon?

Answer 1

To calculate the amount of silicon present in $\;35$ gram atoms we have to use the mole concept and calculate the number of atoms with the help of the average atomic weight of silicon atom.The atomic number of silicon is $14$. The average atomic weight of silicon is $28.085\,amu$.

Complete step by step answer:
Now we will apply the mole concept. The mole concept is a suitable method of expressing the amount of a particular substance. Any measurement is expressed into two parts – the numerical magnitude and the units that the magnitude is expressed in.
In chemistry One mole is defined as the amount of a substance that has exactly$6.02214076\,\, \times {10^{23}}$ ‘elementary entities’ of that substance. The number $6.02214076\,\, \times {10^{23}}$ is called the Avogadro constant and is often represented by the symbol. The elementary entities that are represented in moles could be atoms, molecules, monatomic or polyatomic ions.
One mole of silicon weighs $28.085\,amu$. Gram atoms are also known as moles
Now grams of silicon present in $35gm$ atoms of silicon are $28.085 \times 35 = 980$

Hence, $35gm$ atoms of silicon contains $980gm$ of silicon.

Note:
The atomic mass of an element is the mass of one atom of that element which is expressed in atomic mass units while the molecular mass of any element or compound is the sum of the atomic masses of all elements in that compound.
One mole is defined as the molar mass of the substance. The number of moles of the given sample of an element or compound is calculated by dividing the total mass of the sample by the molar mass of that element.