Which of the following is a clue that a chemical change has taken place?
A.)A gas forms when the change takes place.
B.)The substance is smaller than it was before the change took place.
C.)The substance has been shaken up.
D.)The substance looks the same as it did before the change took place.

A, A gas forms when the change takes place.

Explanation:

Not 100% sure!! I just know that the conditions of chemical change are color change, formation of a gas, odor change, or temperature change

its first and third is your answer i did the qustion the fourth isnt right

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