Question #c839f

1 Answer
Jan 26, 2017

Answer:

and 0.9397g of water. Determine the molecular formula for beta carotene. The molar mass is 536.96

Explanation:

Let the molecular formula of Beta carotene be #C_xH_y# and the balanced equation of its combustion in excess oxygen is as follows.

#C_xH_y+(x+y/4)O_2->xCO_2+y/2H_2O#

It is given that #1g# beta carotene produces #3.278g" "CO_2# and #0.9397g" "H_2O#

Molar mass of BC is #536.96g"/mol"#

So # 1" "mol or 536.96g# BC will produce #3.278xx536.96~~1760.15g" "CO_2# and #0.9397xx536.96~~504.58g" "H_2O#

Molar mass of #CO_2=44g"/mol"#

So number of moles of #CO_2# produced #=(1760.15g)/(44g"/mol")~~40mol#

Hence number of C-atoms in one molecule of BC is #=40# as one molecule of #CO_2# contains one atom of Carbon.

Again Molar mass of #H_2I=18g"/mol"#

So number of moles of #H_2O# produced #=(504.58g)/(18g"/mol")~~28mol#

So one mole BC produces #28mol# water which contain #56# mol atom Hydrogen as one molecule of water contains two atoms of Hydrogen.Hence number of Hydrogen atom present in one molecule of BC is #56#.

Now we can say that molecular formula of BC is #C_40H_56#