NH4NO2(s) = N2(g) + H2O(g)

Question

When a sample is decomposed in a test tube, 646 mL of wet N₂(g) is collected over water at 26°C and 448 torr total pressure.

How many grams of dry NH₄NO₂(s) were initially decomposed? The vapor pressure of water at 26°C is 25.2 torr.

NH4NO2(s) = N2(g) + H2O(g)

Mass is what in grams?

Answer 1

Hi Dayer T.,

First, subtract the vapor pressure of water. That gives you the equivalent pressure of only the dry N2. That + the volume + the temperature + the ideal gas law gives you the #moles N2. Write the balanced equation for the decomposition. (In this case, # moles NH4NO2 = #moles N2, but include this step so you don't forget to always do it!). Convert to #moles NH4NO2 using balanced reaction stoichiometry. Convert to mass using molar mass NH4NO2 (look p, or figure it yourself using a Periodic Table).

-- Cheers, -- Mr. d.