Chemistry teacher gave us this question

Question

Density of iron is 7.87 g/cm3. A student records the mass of a 20.00-cm3 block of iron as 153.8 grams. What is the percent error for the densisty measurement?

Answer 1

given

density = mass / volume

percent error = |theoretical value - recorded value| x 100

theoretical value

then the mass of the block should have been

7.87 g/cm³ x 20 cm³ = 157.4 grams

then the percent error would be

|157.4 - 153.8| x100 = 2.28716645489%

157.4

rounding for 4 sig figs : 2.287 %