Calculate percent error

Question

The accepted ΔH for a reaction is −42.3 kJ/mol. A student has performed a lab experiment to determine the enthalpy change of the same reaction. Calculate the percent error. 

Student 1 Exp. ΔH
Trial 1	-44.0
Trial 2	-41.7
Trial 3	-43.5

Answer 1

Mean for the three trials = -43.1

∆ = 43.1 - 42.3 = 0.8

% error = 0.8/42.3 (x100) = 1.89%