Question

What is the mass (in kg) of 6.89 × 1025 molecules of co2? the molar mass of co2 is 44.01 g/mol.

Answer 1

Answer : The mass of $CO_2$ is, 5.034 Kg

Explanation :

First we have to calculate the moles of $CO_2$.

As, $6.022\times 10^{23}$ molecules of $CO_2$ present in 1 mole of $CO_2$

So, $6.89\times 10^{25}$ molecules of $CO_2$ present in $\frac{6.89\times 10^{25}}{6.022\times 10^{23}}=114.4$ mole of $CO_2$

Now we have to calculate the mass of $CO_2$.

$\text{Mass of }CO_2=\text{Moles of }CO_2\times \text{Molar mass of }CO_2$

$\text{Mass of }CO_2=114.4moles\times 44.01g/mole=5034.744g=5.034Kg$

Therefore, the mass of $CO_2$ is, 5.034 Kg

Answer 2

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles.

 6.89 × 10^25 molecules CO2 ( 1 mole /  6.022 x 10^23 molecules ) ( 44.01 g / mole ) = 5035.35 g CO2 = 5.035 kg CO2