<u>Answer</u>:
A solid will melt at the temperature at which the kinetic energy breaks the
inter-molecular attractions.
<u>Explanation</u>:
The melting point is the state at which "a substance changes its temperature from a solid to liquid". At the melting point temperature, there is an equilibrium between the both the solid and the liquid phase. When the solid particle is heated by increasing the temperature the particle in the solid vibrate quickly and it absorbs kinetic energy.
It leads to the breaking of the organisation of particle in between the solid and that leads to the melting of solid. Thus, at the melting point, the kinetic energy breaks the inter-molecular attractions.
Answer:
The percent yield of the reaction is 82%
Explanation:
First step: make the chemist equation.
2 Al (s) + Fe2O3 (s) → 2 Fe (s) + Al2O3 (s)
As the statement says that aluminun is in excess, the limiting reactant is the Fe2O3
Second step: Find out the moles in the reactant.
Molar weight Fe2O3: 159.7 g/m
Mass / Molar weight = moles
50 g /159.7 g/m = 0.313 moles
Third step: Analyse the reaction. 1 mol of Fe2O3 makes 2 moles of Fe.
1 mol Fe2O3 ____ 2Fe
0.313 mol Fe2O3 ____ 0.626 moles
Molar weight Fe = 55.85 g/m
Moles . molar weight = mass
55.85g/m . 0.626m = 34.9 grams
This will be the 100% yield of the reaction but we only made 28.65 g
34.9 g ____ 100%
28.65 g ____ 82.09 %
Answer :
(A) The balanced chemical reaction will be:

This reaction is a single replacement reaction.
(B) The balanced chemical reaction will be:
This reaction is a double displacement reaction.
(C) The balanced chemical reaction will be:

This reaction is a combination reaction.
Explanation :
Balanced chemical reaction : It is defined as the reaction in which the number of atoms of an element present on reactant side must be equal to the product side.
Part (A):
The balanced chemical reaction will be:

This reaction is a single replacement reaction in which the most reactive element displaces the least reactive element from its solution.
Part (B):
The balanced chemical reaction will be:

This reaction is a double displacement reaction in which a positive cation and a negative anion of two reactants exchange their places to form two new products.
Part (C):
The balanced chemical reaction will be:

This reaction is a combination reaction in which the two atoms combine to form a larger molecule.