What is the mass of H2O obtained when 30g of C2H6 completely reacts with 500 g of O2 (C=12, H=1, O=16)?

options
a) 36.6g b)6g c)54g d) 18g

1 Answer
Feb 4, 2018

The balanced equation is #2C_2H_6 + 7O_2 -> 4CO_2 + 6H_2O#

Molar mass of
#C_2H_6 -> 30g#
#O_2->32g#
#CO_2->44g#
#H_2O->18g#

2 moles of #C_2H_6# is #30*2=60g#
7 moles of #O_2# is #32*7=224g #
produces,
4 moles of #CO_2# is #44*4=176g#
6 moles of #H_2O# is #18*6=108g#.

So according to the question, #30g# of #C_2H_6# should be reacting with #112g# of #O_2# to produce, #88g# of #CO_2# and #54g# of #H_2O#.

p.s . #500-112=388g# of #O_2# remains unreacted as #C_2H_6# is a limiting reagent and gets over before #O_2#.