A student performs an experiment to determine the molar mass of magnesium oxide. The student repeats the experiment five times and collects the following data: 40.220gmol, 40.654gmol, 40.314 gmol, 40.165 gmol, and 40.554 gmol. If the accepted value for the molar mass is 40.304 gmol, what is the percent relative error for the average of this data?

Percent relative error = 0.191%

Explanation:

Relative error is a measure of accuracy (How closeness is the measure to the accepted value) for a determined data. The formula is:

Percent relative error = |Experimental - Accepted| / Accepted * 100

Where experimental is the average of the data:

(40.220g/mol + 40.654g/mol + 40.314g/mol + 40.165g/mol + 40.554g/mol) / 5 =

40.381g/mol

Replacing using accepted value = 40.304g/mol:

|40.381g/mol - 40.304g/mol| / 40.304g/mol * 100

the answer is d.) potassium