When phenolphthalein indicator is added to a colorless solution with a pH of 10, a student observes and concludes that the teste
1 answer:
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Answer:
A
Explanation:
Recall that Δ<em>H</em> is the sum of the heats of formation of the products minus the heat of formation of the reactants multiplied by their respective coefficients. That is:
Therefore, from the chemical equation, we have that:
Remember that the heat of formation of pure elements (e.g. H₂) are zero. Substitute in known values and solve for hydrazine:
In conclusion, our answer is A.
Answer:
(a)
(b) Rubidium
Explanation:
Hello,
This titration is carried out by assuming that the volume of base doesn't have a significant change when the mass is added, thus, we state the following data a apply the down below formula to compute the molarity of the base solution:
Solving for the molarity of base we've got:
Now, we can compute the moles of the base as:
(a) Now, one divides the provided mass over the previously computed moles to get the molecular mass of the unknown base:
(b) Subtracting the atomic mass of oxygen and hydrogen, the metal's atomic mass turns out into:
So, that atomic mass dovetails to the Rubidium's atomic mass.
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Answer:
Raoult's law states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent at the same temperature scaled by the mole fraction of the solvent present: Psolution=χsolventPosolvent.