The true value was 0.120. What was your percent error?

The question is incomplete as the measured value isn't given. However, an hypothesized measured value will be used to explain how to calculate the percentage error.

2.5%

Explanation:

Percentage error :

[(measured value - True value)/ True value] * 100%

The measured value is the value obtained during an while using a measuring device.

If the measured value is = 0.123

Then, the percent error will be :

[(0.123 - 0.120) / 0.120] * 100%

(0.003 / 0.120) * 100%

0.025 * 100%

= 2.5%

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3