Graduated cylinders have numbers on the side that help you determine the volume<span>.</span>
Answer:
B) Heat is given off.
Explanation:
When heat is given off, a chemical change must have occurred and such a reaction is termed an exothermic reaction.
A chemical change is one in which;
- the process is not easily reversible
- leads to the production of new kinds of matter
- involves change in mass
- requires a considerable amount of energy.
Most chemical reactions are accompanied by heat changes.
Answer:
W = - 10.5943 KJ, work is negative because it is carried out by the system towards the surroundings.
Explanation:
heat engine:
∴ Th = 485°C
∴ Tc = 42°C
∴ Qh = 9.75 KJ......heat from hot source
first law:
∴ ΔU = Q + W = 0 .........cyclic process
⇒ Q = - W
∴ Q = Qh + Qc = Qh - (- Qc)
∴ Qc: heat from the cold source ( - )
⇒ Qh - ( - Qc) = - W..............(1)
⇒ Qc/Qh = - Tc/Th...........(2)
from (2):
⇒ Qc = - (Tc/Th)(Qh) = - (42°C/485°C)(9.75 KJ)
⇒ Qc = - 0.8443 KJ
replacing in (1):
⇒ - W = 9.75 KJ - ( - 0.8443 KJ)
⇒ - W = 10.5943 KJ
Because two different equations cannot have the same amount of heat being released unless they are equal and in this case they are not
