What is the key characteristic of an oxidation–reduction reaction?
A.
Electricity is gained.
B.
Electricity is lost.
C.
Electrons are exchanged.
D.
Electrons are gained.
E.
Electrons are lost.

C. Electrons are exchanged

Explanation:

Oxidation-Reduction reaction (Redox) is a type of chemical reaction in which there is a transfer of electrons between the reacting substance.

In this type of reaction, one of the reacting substance, called the Reducing  Agent, undergoes Oxidation (loss of electrons), while the other reacting substance, called the Oxidising Agent ,undergoes Reduction (gains electron).

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.