1. Suppose that there were two isotopes of Sodium. 28% of the naturally occurring sodium atoms had a
mass of 22, and 72% atoms had a mass of 23. What
would the average atomic weight of sodium be?

22.72

Explanation: 28% ➡️ 0.28

72% ➡️ 0.72

(22 x 0.28) + (23 x 0.72) = 6.16 + 16.56 = 22.72

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).