Question

What is the theoretical mass of water produced from ten moles of `NaHCO_3`?

Answer 1

The theoretical mass of water that can be produced by the decomposition of ten moles of sodium bicarbonate is `"90 g"`.

Explanation:

Balanced equation

`"2NaHCO"_3("s")` `rarr` `"Na"_2"CO"_3("s") + "CO"_2("g") + "H"_2"O(g)"`

You first need to determine the number of moles of water produced, then multiply the moles of water produced by its molar mass, `"18.105 g/mol"`.

To calculate the moles of water produced, multiply the moles of `"NaHCO"_3"` by the mole ratio between `"NaHCO"_3"` and `"H"_2"O"` in the balanced equation, with moles `"H"_2"O"` in the numerator.

`10color(red)cancel(color(black)("mol NaCO"_3))xx(1"mol H"_2"O")/(2color(red)cancel(color(black)("mol NaHCO"_3)))="5 mol H"_2"O"`

Calculate the mass of `"H"_2"O"` by multiplying the moles by its molar mass.

`5color(red)cancel(color(black)("mol H"_2"O"))xx(18.015"g H"_2"O")/(1color(red)cancel(color(black)("mol H"_2"O")))="90 g H"_2"O"`