Which of the following statements about balanced chemical equations is true?

they demonstrate that the number of atoms of each element is conserved during a chemical reaction.
they allow the theoretical masses of reactants and products in a chemical reaction to be calculated.
they provide the molar ratios of reactants and products in a chemical reaction.

The correct answer is They provide the molar ratio of reactant and products in a chemical reaction.

Explanation:

Balanced chemical equation helps us to calculate the number of moles of both reactant and product.For example

    2H2+O2=2H2O

From the above balanced equation it can be stated that 2 molecules of hydrogen(H2) reacts with 1 molecule of oxygen(O2) to form 2  molecules of water.

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 :

c, liquids evaporate, creating a gas