Answer:
See explanation
Explanation:
First, we need to use the correct expression:
Q = m*Cp*ΔT (1)
Q = n*ΔH (2)
These are the 2 expressions to calculate heat or energy.
Now, we want to know the change of temperature of the nitrate in water after being added, so with the innitial data of nitrate, we can calculate heat using the second expression. First, we need to calculate moles with the molecular mass:
n = m/MM
n = 42/80.1 = 0.52 moles
With these moles, we can calculate heat with the ΔH of this reaction:
Q = 0.52 * 25.7 = 13.364 kJ or 13,364 J
However, this heat as is being absorbed, the value would be negative.
Now that we have heat, we can use expression (1) and plug these values to solve for ΔT, but before, we need to know the total mass of the solution (water + nitrate)
m = 250 + 42 = 292 g
now, solving for ΔT:
-13,364 = 292 * 4.18 * ΔT
ΔT = -13,363 / (292 * 4.18)
ΔT = -10.95 °C
