Identify four properties of a substance that will never change

Density, boiling point, melting point, condensation point.

Explanation:

The characteristic properties of a chemical substance are defined as the fixed and unique properties that are used for the identification and the classification of the given substance.

They can be physical as well as chemical properties such as density, solubility, freezing point, boiling point, melting point, condensation point, and viscosity.

if you mean hydrogen and oxygen then water is the product

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 :