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(kJ/mol)
Trial 1 –43.8
Trial 2 –41.0
Trial 3 –42.7

trial 1: % error = 3.546 %

trial 2: % error = 3.073 %

trial 3: % error = 0.946 %

Explanation:

∴ ΔH = - 42.3 KJ/mol

trial 1:

∴ ΔH1 = - 43.8 KJ/mol

⇒ % error = ((-43.8 - ( -42.3 )) / ( -42.3 ))×100

⇒ % error = (0.03546)*100 = 3.546 %

trial 2:

∴ ΔH2 = - 41.0 KJ/mol

⇒ % error = ((-42.3 - ( -41.0 )) / ( -42.3 ))×100

⇒ % error = (0.03073)*100 = 3.073%

trial 3:

∴ ΔH3 = - 42.7 KJ/mol

⇒ % error = ((-42.7 - ( -42.3 )) / ( -42.3 ))×100

⇒ % error = (9.456 E-3)*100 = 0.946 %

the only liquid elements at standard temperature and pressure are bromine (br) and mercury (hg). although, elements caesium (cs), rubidium (rb), francium (fr) and gallium (ga) become liquid at or just above room temperature.

explanation:

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.