The addition of 3.72 g of Ba(OH)2 · 8 H2O to a solution of 1.26 g of NH4SCN in 133 g of water in a calorimeter caused the temperature to fall by 4.3°C. Assuming the specific heat of the solution and products is 4.20 J/g·°C, calculate the approximate amount of heat (in J) absorbed by the reaction, which can be represented by the following equation. Ba(OH)2 · 8 H2O(s) + 2 NH4SCN(aq) → Ba(SCN)2(aq) + 2 NH3(aq) + 10 H2O(l)

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thomasdecabooter thomasdecabooter · Answer 1 · 2019-11-09T00:38:46+01:00

Answer:

The amount of heat absorbed by the reaction is 2491.92 J

Explanation:

Step 1: The balanced equation

Ba(OH)2 · 8 H2O(s) + 2 NH4SCN(aq) → Ba(SCN)2(aq) + 2 NH3(aq) + 10 H2O(l)

Step 2: Data given

mass of Ba(OH)2 · 8 H2O(s) = 3.72g

Molar mass of Ba(OH)2 · 8 H2O(s) = 315.46 g/mol

mass of NH4SCN = 1.26 g

Molar mass of NH4SCN = 76.122 g/mol

mass of water = 133g

Molar mass of water = 18.02 g/mol

Temperature decreases with 4.3 °C this is an endothermic reaction

specific heat of the solution and products is 4.20 J/g·°C

Step 3: Calculate heat transfer

Q = m*c*ΔT

with m = the mass = mass of Ba(OH)2 · 8 H2O + mass of NH4SCN + mass of water = 3.72 + 1.26 + 133 = 137.98

with c = the specific heat capacity of the solution = 4.20 J/g°C

with ΔT = The change in temperature = 4.3 °C

Q = 137.98 * 4.20 * 4.3 = 2491.92 J

The amount of heat absorbed by the reaction is 2491.92 J