Question

a) Calculate the molar mass of CH14. 1.2 b) Calculate the number of moles of hexane in 0.774 g of C&H14. c) Calculate the mass in grams of 0.0406 moles of hexane.

Answer 1

las GHIA - (6x12.0107 + 19 x 1-0079A) 9/mol = 86.1*7536 8/mol I so, molar mass of Ghia is 86.17 536 81 mor. Ics Scanned with CamScanner

b) 0.77A & CHA more = given mass 1. Moler mass = 0.7748 . 86:17 536 9/mol = 8.98 x 10-3 mole so, the no. of moles=8.98 x 10-3 10-3 mole. mol C 0.0406 moll= mass 86.175368/mol mass=3.4 g so, the answers are above cs Scanned with CamScanner

Answer 2

Ans: a) molar mass of hexane = 86.172 g / mol

        b) moles of hexane = 8.9 x 10^-3 moles

        c) mass of hexane = 3.498 g

Solution:

a) Molar mass of hexane (C₆H₁₄) = ?

Molar mass of C₆H₁₄ = (6 x atomic mass of C) + (14 x atomic mass of H)

                                    = (6 x 12.0107) + (14 x 1.008)

                                    = 72.06 + 14.112 =  86.172 g/ mol

b) Given: mass of hexane = 0.774 g

     no. of moles of hexane = ?

Molar mass of hexane = 86 g / mol  (above calculated in part a)

Formula used to calculate no. of moles of hexane:

No. of moles of hexane  = mass of hexane / Molar mass of hexane 

Now, putting the given values in above formula:

no. of moles = 0.774 g / 86.172 gxmol-1

                    = 0.0089 moles = 8.9 x 10-3 moles             

c) Given: 

Moles of hexane = 0.0406

mass of hexane = ?

Fomula using to calculate mass of hexane:

mass of hexane = no. of moles of hexane x molar mass of hexane

Now, putting given values in above formula:

mass of hexane = 0.0406 moles x 86.172 g / mol

                          = 3.498 g