What happens in a reaction if it is at chemical equilibrium?
a. there are no reactants in the system.
b. all of the products are used up.
c. the amount of the reactant is constantly decreasing.
d. the rate of the forward reaction equals the rate of the reverse reaction.

The answer is D

Explanation:

In a chemical equilibrium, the forward and reverse reactions occur at equal rates, and the concentrations of products and reactants remain constant. A catalyst speeds up the rate of a chemical reaction, but has no effect upon the equilibrium position for that reaction.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.

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