Question

the qrxn is -4,610 j when 1.00 g k dissociates in water. what is the enthalpy of the reaction? δhₓₙ = ? kj/mol enter either a + or - sign and the magnitude.

Explanation:

Step1: Find moles of K

Molar mass of K is 39.10 g/mol. Moles ($n$) = mass / molar mass.
$n = \frac{1.00\ g}{39.10\ g/mol} \approx 0.02557\ mol$

Step2: Convert q to kJ

$q_{rxn} = -4610\ J = -4.610\ kJ$ (since 1 kJ = 1000 J)

Step3: Calculate $\Delta H_{rxn}$

$\Delta H_{rxn} = \frac{q_{rxn}}{n}$
$\Delta H_{rxn} = \frac{-4.610\ kJ}{0.02557\ mol} \approx -180.3\ kJ/mol$ (rounded appropriately)

Answer:

-180 kJ/mol (or more precisely -180.3 kJ/mol, depending on rounding)