Question

Students in Mr. Klein’s chemistry class are conducting an experiment to calculate the specific heat of a copper sample. Mr. Klein requires each lab team to repeat the experiment until their percent error is 2% or less. Percent error is calculated using observed values (those students calculate from their lab results) and the true value (the accepted value based on reference). The formula for percent error is:

(observed – true) x 100
true
If the accepted value for the specific heat of copper is 0.385 J/g°C, which of the following lab
teams have an unresolved problem on their hands?
a.
team 1: calculates 0.390 J/gºC
b.
team 2: calculates 0.395 J/gºC
c.
both teams
d.
neither team

Answer 1

Percent error in team 1 value:

(0.392 - 0.385)/0.385 x 100

= 1.81%

Percent error in team 2 value:

(0.395 - 0.385)/0.385 x 100

= 2.60%

B. Team 2 has an unresolved issue in on their hands, resulting in greater than acceptable error.