Answer : The value of 
for this reaction is 36.18 kJ
Explanation :
First law of thermodynamic : It states that the energy can not be created or destroyed, it can only change or transfer from one state to another state.
As per first law of thermodynamic,
where,
= internal energy of the system
q = heat added or rejected by the system
w = work done
As we are given that:
q = 38.65 kJ
w = -2.47 kJ (system work done on surrounding)
Now put all the given values in the above expression, we get:
Therefore, the value of for this reaction is 36.18 kJ
The average acceleration is -5.0 m·s⁻².
The formula for acceleration (<em>a</em>) is
= 25 m·s⁻¹; 
= 0; 
= 5.0 s
∴ 
= -5.0 m·s⁻²
The negative sign tells you that the object is <em>slowing down</em>, i.e., it is <em>decelerating</em>.
Answer:
Near the boiling point of the solvent
Explanation:
The process of recrystallization is hinged on the fact that the amount of solute that can be dissolved by a solvent increases with temperature. The process involves creation of a solution by dissolving a solute in a solvent at or near its boiling point. At the boiling point of the solvent, the solute has a greater solubility in the solvent; not much volume of the hot solvent is required to dissolve the solute.
Before the solution is later cooled, you can now filter out insoluble impurities from the hot solvent. The quantity of the original solute drops appreciably because impurities have been removed. At this lower temperature, the solution becomes saturated and the solute can no longer be held in solution hence it forms pure crystals of solute, which can be recovered.
Recrystallization must be carried out using the proper solvent. The solute must be relatively insoluble in the solvent at room temperature but more soluble in the solvent at elevated temperature.
Answer:
I think option A is right answer
Answer:
The most important ore of aluminum is<u> Bauxite.</u>
And its chemical formula is 
.
Explanation:
Bauxite is the most important ore of Aluminium from which Aluminium is extracted. Bauxite is a rock and composed of Aluminium bearing mineral.
And its chemical formula is .
It contains Gibbsite, Bohmite and Diaspore along with iron.
It is a soft material with somewhat white to grey to reddish brown in colour.
It has an earthy lustre and low specific gravity.
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