what mass of water forms when 123.3 g of methane burns?

Answer 1

hello!
the best ways ot answer this question is to firt write the equation of the reaction! then i will be easy to balance with the stoeckiometric number!
so the equation looks like this
CH4 + O2 ==> H2O + CO2 (you have to equilibrate it)
it is now!

CH4 + 2O2 ==> 2 H2O + CO2

now we can find it !
n(CH4) = n(H2O)/2<==>2*m(CH4)/M(CH4)= m(H2O)/M(H2O)

<==> m(H2O)=(2*m(CH4)* M(H2O) / ( M(CH4) ) )
so we have m(H2O)= 2*123.3*18 / 18 = 246.6g

CH4 and H2O have the same Molecular masse so it would be easier to be easier to compare directly each stoeckiometric number! 1 for CH4 and 2 for H2O that mean when one mole of Methane is used we have as product 2 moles of whater! since they have the molecular mass! that means the mass of water is the double of that of methane!
so 246.6g

I hope i was useful!

Ngani Patrick K.
http://blog.360.yahoo.com/blog-QF3bNVIherIwEswcliX.wg--?cq=1

Answer 2

123.3/16 x 2 x 18