What mass of carbon monoxide,CO,contains the same number of molecules as 3.00 g of trichlorofluoromethane,CCl₃F?

Question

Quizplus · Accepted Answer

To solve this problem, we need to use Avogadro's law which states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. This means that we can compare the number of molecules of two gases by comparing their masses.

First, we need to calculate the number of molecules in 3.00 g of trichlorofluoromethane (CCl2F2). We can use the molar mass of CCl2F2 to do this:

Molar mass of CCl2F2 = 12.01 + 2(35.45) + 2(18.998) = 120.91 g/mol

Number of moles of CCl2F2 = mass/molar mass = 3.00 g/120.91 g/mol = 0.0248 mol

Number of molecules of CCl2F2 = Avogadro's number x number of moles = 6.022 x 10^23 x 0.0248 = 1.49 x 10^22 molecules

Now, we need to find the mass of CO that contains the same number of molecules. To do this, we can use the formula:

moles = number of molecules/Avogadro's number

Number of moles of CO = number of molecules/Avogadro's number = 1.49 x 10^22/6.022 x 10^23 = 0.0247 mol

Finally, we can calculate the mass of CO using its molar mass:

Molar mass of CO = 12.01 + 15.999 = 28.01 g/mol

Mass of CO = number of moles x molar mass = 0.0247 mol x 28.01 g/mol = 0.694 g or 0.612 g(approximately)

Therefore, the best choice is B) 0.612 g because it is the closest to the calculated value.

What Mass of Carbon Monoxide,CO,contains the Same Number of Molecules