Question

What is the mass of 4.91 x10^21 platinum atoms?

Answer 1

To calculate the mass, go from atoms to moles and moles to grams:

Atoms ........ Moles.......... Grams

From atoms to moles, use the Avogadro’s no. which is 6.022 x 10^23 and from moles to grams use atomic mass of Pt that is 195.08g.

So, 4.91 x 10^21 Pt atoms x (1 mole Pt / 6.022x10^23 Pt atoms) x (195.08g Pt / 1 mole Pt) = 1.59g Pt

Mass of 4.91 x 10^21 Pt atoms = 1.59g Pt

Answer 2

The mass of $4.91 \times {10^{21}}{\text{ platinum atoms}}$ is $\boxed{1.59{\text{ g}}}$.

Further Explanation:

We are provided with atoms of platinum and its mass is to be calculated. For this, first of all atoms of Pt are to be converted into moles. This is done with the help of Avogadro’s law. According to Avogadro’s law, one mole of any substance contains $6.022 \times {10^{23}}{\text{ units}}$. Such units can be atoms and molecules.

Since $6.022 \times {10^{23}}$ of platinum consist of one mole, number of moles that are present in $4.91 \times {10^{21}}{\text{ atoms}}$ can be calculated as follows:

 $\begin{aligned}{\text{Moles of Pt}} &= \left( {4.91 \times {{10}^{21}}{\text{ atoms}}} \right)\left( {\frac{{1{\text{ mol}}}}{{6.022 \times {{10}^{23}}{\text{ atoms}}}}} \right) \\&= 0.008153{\text{ mol}} \\\end{aligned}$

Now moles calculated in above step are used to proceed for further calculations of mass. Moles and mass of Pt are related to each other with the help of expression written below.

The formula to calculate moles of Pt is as follows:

${\text{Moles of Pt}} = \dfrac{{{\text{Mass of Pt}}}}{{{\text{Molar mass of Pt}}}}$                                                                    ……(1)

Rearrange equation (1) to calculate mass of Pt.

${\text{Mass of Pt}} = \left( {{\text{Moles of Pt}}} \right)\left( {{\text{Molar mass of Pt}}} \right)$                                            …… (2)

The moles of Pt are0.008153 mol.

The molar mass of Pt is 195.084 g/mol.

Substitute these values in equation (2).

$\begin{aligned}{\text{Mass of Pt}} &= \left( {{\text{0}}{\text{.008153 mol}}} \right)\left( {{\text{195}}{\text{.084 g/mol}}} \right)\\&= 1.59{\text{ g}} \\\end{aligned}$  

Hence,mass of platinum comes out to be 1.59 g.

Learn more:

1. Law of conservation of matter states: brainly.com/question/2190120
2. Calculation of volume of gas: brainly.com/question/3636135

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Mole concept

Keywords: mole, atoms, Pt, platinum, moles of Pt, molar mass of Pt, 1.59 g, Avogadro’s law, 6.022*10^23 atoms, 4.91*10^21 atoms, mass of Pt, 195.084 g/mol, 0.008153 mol, mass of platinum.