Red phosphorus reacts with liquid bromine in an exothermic reaction `2P(s) + 3 Br_(2) (l) rarr PBr_(3) (g), Delta_(r) H^(@) = - 243 kJ mol^(-1)` Calculated the enthalpy change when `2.63 g` of phosphorus reacts with an excess of bromine in this way.A. `10.3 kJ`B. `1536 kJ`C. `7.5 kJ`D. `20.3 kJ`

Red phosphorus reacts with liquid bromine in an exothermic reaction `2

1.	Red phosphorus reacts with liquid bromine in an exothermic reaction `2P(s) + 3 Br_(2) (l) rarr PBr_(3) (g), Delta_(r) H^(@) = - 243 kJ mol^(-1)` Calculated the enthalpy change when `2.63 g` of phosphorus reacts with an excess of bromine in this way.A. `10.3 kJ`B. `1536 kJ`C. `7.5 kJ`D. `20.3 kJ`
Answer» Correct Answer - A Calculate the number of moles of `P` and mulitply it with `Delta_(r) H^(@)` for 1 mol of `P`. `n_(P) = (Mass_(P))/(Molar mass_(P)) = (2.63 g)/(30.97 mol^(-1)) = 0.0849 of P` `Delta H = (0.0849 mol) ((-243 kJ)/(2 mol P))` `= 10.3 kJ`

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Red phosphorus reacts with liquid bromine in an exothermic reaction `2P(s) + 3 Br_(2) (l) rarr PBr_(3) (g), Delta_(r) H^(@) = - 243 kJ mol^(-1)` Calculated the enthalpy change when `2.63 g` of phosphorus reacts with an excess of bromine in this way.A. `10.3 kJ`B. `1536 kJ`C. `7.5 kJ`D. `20.3 kJ`

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