When it comes to physical changes like phase changes, there are two types of heat energy: sensible heat and latent heat. Sensible heat is the heat absorbed/released when you heat the substance but it doesn't change phase. An example would be heating lukewarm water. The substance is liquid all throughout. Latent heat, on the other hand, is the heat absorbed/released when there is a phase change. An example would be boiling water, because it changes liquid to vapor.
Hence, for freezing liquid, you use the latent heat, specifically the heat of fusion. The answer should be
2.5 g * (1 mol/18.02 g) * 6.03 kJ/mol = 0.84 kJ/mol
The answer is not in the choices. You only use Hvap if you boil water.
Answer:
1. Source of carbon
2. Removal of cuticle
Explanation:
You may have been doing a photosynthesis lab in a biology course.
1. NaHCO₃
The purpose of creating a sodium bicarbonate solution was to provide the carbon that the plant needs for photosynthesis.
2. Soap solution
The soap solution acted as a detergent. It removed some of the waxy, water-repelling cuticle from the leaf's surface and made it easier for the sodium carbonate solution to get inside.
There is a change of decrease in entropy in 3Fe(s) + 202(g) -. Fe 304(g)
There is a decrease in a gaseous molecule, which causes a disorder in the system.
Your answer is: 3Fe(s) + 202(g) -. Fe304(g)
Have an amazing day and stay hopeful!
I'm not a 100% sure but I'd go for option A). 7700 Joules
