# Percent error help in chemistry?

I need to calculate the percent error of Nickel, I calculated its heat capacity as

0.42, the actual value is 0.440. What is the percent error?

Relevance

Percent error values try to give a sense of just how badly (or how well) your measured (or experimental) value matches the true (or accepted) value. It does so according to the formula:

% Error = [ (experimental value - true value) / true value] x 100

[ (0.42 - 0.440) / 0.440 ] x 100 =

[       (-0.02)     / 0.440 ] x 100 =

[              -0.05           ] x 100 = -5%

BUT one is not concerned with the 'direction' of the error, one reports the absolute value—the positive value—of the result.

>> Thus, the percent error for your heat capacity experiment is: 5%

(ASIDE: Note that the subtraction step yielded a number (-0.02) that is only good to one significant figure. Because all following math operations were either multiplication or division, and your final answer can only be good to one sig fig. Had your measured value been 0.420 (with a zero after the two), the answer would have been 4.6%)

• Anonymous
8 years ago

simple math

0.440 = 100%

=> 0.42 = 0.42/0.440 * 100 = 95.4545....%