Question

what is the heat of reaction, qrxn, for the salt dissociating? ca(oh)₂ → ca²⁺ + 2oh⁻ qsoln = +1620 j qcal = +57 j qrxn = −(qcal + qsoln) qrxn = ? j enter either a + or - sign and the magnitude.

Explanation:

Step1: Calculate the sum of \( q_{cal} \) and \( q_{soln} \)

We know that \( q_{soln} = +1620 \, \text{J} \) and \( q_{cal} = +57 \, \text{J} \). So we add these two values: \( 1620 + 57 = 1677 \, \text{J} \).

Step2: Apply the formula for \( q_{rxn} \)

The formula given is \( q_{rxn} = -(q_{cal} + q_{soln}) \). We already found that \( q_{cal} + q_{soln} = 1677 \, \text{J} \), so we substitute this into the formula: \( q_{rxn} = -1677 \, \text{J} \).

Answer:

\(-1677\)