MHT CET202527 Apr 2025Evening ShiftChemistrySome Basic Concepts of ChemistryActual
Calculate mass of 0.25 mole of iron (molar mass =56 ~g ~mol ⁻¹ )
Options
- A5.6 10⁻² ~kg
- B1.4 10⁻² ~kg
- C2.8 10⁻² ~kg
- D4.2 10⁻² ~kg
Correct answer
A. 5.6 10⁻² ~kg
Step-by-step solution
The mass m of a substance is given by m = n M , where n is the number of moles and M is the molar mass. For iron, with n = 0.25 , mol and M = 56 , g , mol ⁻¹ , the mass is m = 0.25 56 = 14 , g . Converting to kilograms: 14 , g = 14 10⁻³ , kg = 0.014 , kg . In scientific notation, the mass is 1.4 10⁻² , kg , which corresponds to option B .