3 points 18) A student determines the density of gold to be 20.9g/L. The true
density of gold is 19.30g/L. What is the student's percent error?round
answer to 2 significant figures *

Explanation:

The percentage error of a certain measurement can be found by using the formula

From the question

actual density = 19.30g/L

error = 20.9 - 19.3 = 1.6

We have

We have the final answer as

Hope this helps you

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).