E. The nuclear fuel in the stars will eventually burn out, making the universe a cold and dark place
Answer: a. 0.75m (NH4)3PO4 will have the lowest freezing point .
Explanation: Freezing point decreases as the concentration of the solute substance increases. Assuming the same solvent for all of them, for instance water.
∆T= i.Kf.b
∆T= freezing point depression
i= vant Hoff factor
Kf= molality
Assuming water to be the solvent for all Kf=1.86°C/M
VANT HOFF FACTORS :
For (NH4)3PO4
This has 3 ionic bonding and 1 covalent bonding making it 4 bond
Therefore i=4
For CaSO4
This has 1 metallic bond and 1 covalent bond making it 2 bond.
Therefore i=2
For LiCl
This has 1 metallic bond and 1 non metallic bond making it 2 bond.
Therefore i=2
For CH3OH
This has only 1 covalent bond.
Therefore i=1
MOLALITY:
(NH4)3PO4 = 0.75M
CaSO4= 1.0M
LiCl= 1.0M
CH3OH= 1.5M
FREEZING POINT DEPRESSION:
For (NH4)3PO4
∆T= 4×0.75×1.86=5.58°C
For CaSO4
∆T= 2×1.0×1.86=3.72°C
For LiCl
∆T = 2×1.0×1.86= 3.72°C
For CH3OH
∆T= 1×1.5×1.86=2.79°C
REMEMBER THE HIGHER THE FREEZING POINT DEPRESSION THE LOWER THE FREEZING POINT.
FREEZING POINT DEPRESSION IS THE CHANGE IN THE FREEZING POINT PROPORTIONAL TO THE AMOUNT OF SOLUTE ADDED THE THE SOLUTION.
THEREFORE THE ONE WITH THE LOWEST FREEZING POINT IS (NH4)3PO4
Answer:
3.5 mol KClO3
Explanation:
Given 3.50 moles of KCl as the target amount in the problem, used the coefficient of the balanced chemical reaction involved to determine the number of moles of potassium perchlorate needed.
x mole of KClO3 = 3.5 mol KCl x [(2 mol KCl)/ (2 mol KClO3)] = 3.5 mol KClO3
x mole of KClO3 = 3.5 mol KClO3
The correct answer is A. An element cannot be separated into simpler substances or converted into another substance by chemical processes. Elements are the most simplest form of the chemicals. They are what we see in the periodic table.
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