Answer to Question #99889 in General Chemistry for Beverlie

Question

In some aquatic ecosystems, nitrate (NO3–) is converted to nitrite (NO2–), which then decomposes to nitrogen and water. As an example of this second reaction, consider the decomposition of ammonium nitrite: NH4NO2(aq) = N2(q)+2H2O(l)
What would be the change in pressure in a sealed 10.0 L vessel due to the formation of N2 gas when the ammonium nitrite in 1.40 L of 0.900 M NH4NO2 decomposes at 25.0°C? answer in atm

Answer 1

$$NH_4NO_2 \rightarrow N_2 + 2H_2O$$

Find moles of NH4NO2

$n=c\times V= 0.900\times 1.40 = 1.26 mol$

Accordring to equation $n(N_2) = n(NH_4NO_3) = 1.26 mol$

Use Ideal gas law to find pressure:

$$PV = nRT$$

$T(K) = 273 + 25 = 298 K$

$V= V_{vessel}-V_{solution}= 10.0-1.4 =8.6 L$

$$P\times 8.6 = 1.26\times 0.082\times298$$

$$P = 3.58 atm$$