Chemistry exercises 2

Question

I need help with these 2? Someone ??

In aerospace Li2O is used to bind the exhaled CO2. How many litres of CO2 gas at 25 °C and 1010 hPa can bind 1 kg of Li2O ?

Li2O + CO2 -> i2 CO3

 When HgO is heated, 25 ml of O2 can be collected at 35 °C under a pressure of 1025 hPa. How much HgO is decomposed here ?

2 HgO -> 2 Hg + O2

thank y’all

Answer 1

1) One approach, which I will use here, is to find the volume of CO₂ that would be produced at STP, then convert this, using the combined gas law, to the given conditions.

Li₂O + CO₂ → Li₂CO₃

(22.4 L CO₂/1 mol CO₂) (1 mol CO₂/1 mol Li₂CO₃) (1 mol Li₂CO₃/30.0 g Li₂CO₃) 1000 g Li₂CO₃ = 747 L CO₂

P_SV_S/T_S = P₂V₂/T₂

V₂ = [(1.013 x 10⁵Pa) (747 L) (298.15 K) (1 hPa)]/[(1010 hPa) (100 hPa) (273.15 K)] = 817 L

2) This is somewhat the reverse of the previous question. Here, the best approach is to use the CGL to convert the given volume at the given conditions to STP, then use stoichiometry to get the mass of HgO

V_s = P₁V₁T_s/P_sT₁

= [(1025 hPa) (100 Pa) (0.025L) (273.15 K)]/[(1 hPa) (1.013 x 10⁵Pa)(308.15 K)] = 0.0224 L

(217 g HgO/ 1 mol HgO) (2 mol HgO/1 mol O₂) (1 mol O₂/22.4 L) 0.0224 L = 0.434 g HgO