10618 G of an Unknown Salt Is Dissolved in a Coffee

question 79

Multiple Choice

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water. The measured temperature decreased from 23.8 °C to 22.7 °C. Identify the unknown salt. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

• A)NaF, Δ_rH = 0.91 kJ mol^-1
• B)NaBr, Δ_rH = -0.60 kJ mol^-1
• C)NaNO₃, Δ_rH = 20.50 kJ mol^-1
• D)LiNO₃, Δ_rH = -2.51 kJ mol^-1
• E)LiBr∙2H₂O, Δ_rH = -23.26 kJ mol^-1