Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2h2o2(l) → 2h2o(l) + o2(g) δh = -196 kj calculate the value of q (kj) in this exothermic reaction when 2.50 g of hydrogen peroxide decomposes at constant pressure.

The amount of heat released is -7.203 kJ

Explanation:

The given chemical equation follows:

To calculate the enthalpy change for 1 mole of the hydrogen peroxide, we use unitary method:

When 2 moles of hydrogen peroxide is reacted, the enthalpy of the reaction is -196 kJ

So, when 1 mole of hydrogen peroxide will react, the enthalpy of the reaction will be

Given mass of hydrogen peroxide = 2.50 g

Molar mass of hydrogen peroxide = 34 g/mol

Putting values in above equation, we get:

where,

= amount of heat released

n = number of moles = 0.0735 moles

= enthalpy change of the reaction = -98 kJ/mol

Putting values in above equation, we get:

Hence, the amount of heat released is -7.203 kJ

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