To determine whether the crown was made of pure gold or not, we need to compare the density of gold (19.3 g/mL) to the density of the crown.
The formula for density is
we know the mass of the crown is 714 grams and its volume is 38.3 mL. (Because it displaces 38.3 mL of water)
Using this information, we can plug the numbers into our density formula to solve for the density of the crown.
The density of the crown is 18.6 g/mL, thus the crown was not made of pure gold, as that has a density of 19.3 g/mL. In conclusion, the goldsmith tried to screw over the king.
If the change in Gibbs free energy for a process is positive, the corresponding change in entropy for the universe will be positive.
<h3>What is Gibbs free energy?</h3>
This is defined as the energy used by a substance involved in a chemical reaction.
The Gibbs free energy and entropy has a direct relationship which is why a positive gibbs free energy will result in a corresponding positive entropy.
Read more about Gibbs free energy here brainly.com/question/9179942
Answer:
Br2 (l) + 2e- ---------> 2Br- (aq) E° = 1.08 V cathode
Cu2+ (aq) + e- --------->Cu+ (aq) E° = 0.15 V anode
Explanation:
We have to first state the fact that the reaction having the most positive reduction potential occurs at the cathode in any spontaneous electrochemical cell. The half reaction with the less positive electrode potential usually occurs at the anode.
The overall reaction equation is;
2Cu2+ (aq) + Br2 (l) ----->2Cu+ (aq) + 2Br- (aq)
E°cell= E°cathode - E°anode
E°cathode= 1.08 V
E°anode= 0.15V
E°cell = 1.08-0.15 = 0.93 V
But
∆G°= -nFE°cell
n= 2, F=96500C, E°cell= 0.93V
∆G° = -(2× 96500× 0.93)
∆G= -179490 J
But;
∆G = -RTlnK
R=8.314 JK-1
T= 25+273= 298K
Kc= the unknown
∆G° = -179490 J
Substituting values and making lnK the subject of the formula
lnK= ∆G/-RT
lnK= -( -179490/8.314 × 298)
lnK= 72.45
K= e^72.45
K= 2.91×10^31
