Question

How many moles are in 10 g of calcium?
(at mass of ca=40u)

Answer 1

Explanation:

How many moles and how many atoms are there in 10 grams of calcium?

0.25 mole is correct answer

Answer 2

Solution :-

Atomic Mass of Calcium (Ca) = 40 u

Molar Mass of Calcium, M = 40 g/mol

Given Mass, m = 10 g of Calcium

$\begin {gathered} \end {gathered}$

∴ The Number of Moles in 10 g of Calcium (Ca)

$\boxed {\mathtt {Number\: of\: Moles, n} = \dfrac{\mathtt {Given\: Mass, m}}{\mathtt {Molar\: Mass, M}}}$

$\Rightarrow \bold n = \dfrac{1 \cancel 0}{4 \cancel 0} = \dfrac{1}{4} = \bold {0.25\: moles}$

$\begin {gathered} \end {gathered}$

Hence, There are 0.25 Moles in 10 g of Calcium . . .

$\begin {gathered} \end {gathered}$

Additional Information :-

Molar Mass :- Mass of 1 Mole of a Substance is called its Molar Mass.

Molar Mass of Atoms is also known as Gram Atomic Mass . . .

$\begin {gathered} \end {gathered}$

For Example,

Atomic Mass of Hydrogen = 1 u

So, Molar Mass (Gram Atomic Mass) of Hydrogen = 1 g

1 u Hydrogen has only 1 Atom of Hydrogen, 1 g of Hydrogen has 1 Mole Atoms, i.e., $\mathtt{6.022 \times 10^{23}}$ atoms of Hydrogen . . .

$\begin {gathered} \end {gathered}$

Mole Concept :-

The Mole is the Amount of Substance of a System that contains $\mathtt{6.022 \times 10^{23}}$ specified Elementary Entities. It is Equal to its Relative Atomic/ Molecular Mass (in grams) . . .

1 Mole = $\mathtt{6.022 \times 10^{23}}$ in Number

$\begin {gathered} \end {gathered}$

Avogadro Number :- The Avogadro Constant $\mathtt{6.022 \times 10^{23}}$ is defined as the Number of Atoms in exactly 12 g of Carbon - 12 Isotope.