Question

Calculate the mass in grams of 1.72×10^24 molecules of formaldehyde. The chemical formula for formaldehyde is CH2O.

Answer 1

Answer: m= 85.8 g CH2O

Explanation: First step is convert the molecules of CH2O to moles using the Avogadro's Number.

1.72x10²⁴ molecules CH2O x 1 mole CH2O / 6.022x10²³ molecules CH2O

= 2.86 moles CH2O

Next is convert the moles of CH2O to mass using the molar mass of CH2O

2.86 moles CH2O x 30 g CH2O / 1 mole CH2O

= 85.8 g CH2O