Question

The no of atoms present in 4 gram of calcium is

Answer 1

Molar mass of calcium = 40 g/mol
Therefore, 40 g of calcium = 1 mole of calcium
No of moles in 4 g = 440 = 0.1 mol

Now, no of atoms in one mole of any substance remains constant, i.e 6.022 × 1023

So 0.1 mol of calcium will contain same no of atoms as in 0.1 mol of neon.

Molar mass of neon = 20 g/mol
Therefore, 20 g of neon = 1 mole of neon​
0.1 mol will contain 2 g of neon
Hence 2 gm of neon will have the same no of atom as in 4 gm of calcium.

Answer 2

Answer:

The count of atoms present in $4$ gram of calcium is $0.6023 \times {10^{23}}$.

Explanation:

Concept: By knowing the quantity of moles or the mass of the substance in the sample, the number of atoms present may be estimated. The number of moles in the sample can be used to define the atoms or molecules that are present in it. This can be applied to the conversion effectively. The molar mass is stated in g/mole whereas the mass of an atom is often expressed in grammes.

Given: It is given that calcium has a mass of $4$ gram and a molar mass of $40 g/mol$, we can infer its composition.

To find:

We have to find the count of atoms in four gram of calcium.

Solution:

One mole of any substance contain the count of atoms equal to $6.022*10^{23}$.

Thus, Count of moles of calcium$(n)$$=$ mass of the calcium$(m)$ / Molecular mass of calcium $(M)$

$n =$$\frac{4}{40}$ mole

$n =$$\frac{1}{10}$ mole

$n= 0.1$ mole

We know that One mole of any substances contain the $=6.022*10^{23}$. atoms.

$0.1$ mole contains,

$=6.022*10^{23}*0.1$

$=$$0.6023 \times {10^{23}}$ atoms

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