A handbook gives the density of calcium as #"1.62 g/cm"^3#. What is the percent error of a density calculation of #"1.37 g/cm"^3# based on lab measurements?

1 Answer
Sep 20, 2017

Answer:

#15.4%#

Explanation:

Your tool of choice here will be the following equation

#"% error" = (|"accepted value " - " measured value"|)/"accepted value" * 100%#

So what you're looking for here is the absolute value of the difference between the accepted value and the measured value expressed as a percentage of the accepted value.

In your case, you have

  • #"accepted value" = "1.62 g cm"^(-3)#
  • #"measured value" = "1.37 g cm"^(-3)#

Plug this in the equation to get

#"% error" = (|(1.62 - 1.37)color(red)(cancel(color(black)("g cm"^(-3))))|)/(1.62color(red)(cancel(color(black)("g cm"^(-3))))) * 100%#

#color(darkgreen)(ul(color(black)("% error" = 15.4%)))#

The answer is rounded to three sig figs.