The composition of a compound does not vary because it is made up of fix ratio by mass.
<h3>What is compound?</h3>
A compound is a chemical substance that is composed of more than one element that held together by chemical bonds and produces fix ratio by mass so we can conclude that the composition of a compound does not vary because it is made up of fix ratio by mass.
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(1) The quantity of heat required to melt 175 g Cu is 35.88 kJ.
(2) The substance that releases 21.2 kJ of energy when 1.42 mol of it freezes is iron.
<h3>
What is heat of fusion?</h3>
Heat of fusion is the energy required to melt 1 mole of a substance.
<h3>What is heat of vaporization?</h3>
The heat energy required to vaporize 1 mole of a substance has been heat of vaporization.
Heat of fusion of copper (Cu) is given as 13 kJ/mol
Number of moles of 175 g of copper = 175/63.5 = 2.76 moles
Q = nΔH
Q = 2.76 mol x 13 kJ/mol = 35.88 kJ
Thus, the quantity of heat required to melt 175 g Cu is 35.88 kJ.
<h3>Heat of fusion of the substance</h3>
ΔH(fus) = Q/n
where;
- n is number of moles
- Q is quantity of heat released
ΔH(fus) = 21.2 kJ / 1.42 mol
ΔH(fus) = 14.93 kJ/mol
From the table the substance with latent heat of fusion of 14.9 kJ/mol is iron.
Thus, the substance that releases 21.2 kJ of energy when 1.42 mol of it freezes is iron.
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Gravitation Potential energy is converted into the Kinetic Energy, when it just reaches the ground. Some amount of energy is wasted in sound and heat energy when it strikes the ground. When the apple falls from the tree, it has some gravitational potential energy due to its height.
Ne because it it just a regular element (neon)