Answer:
(C) Mass of KCl(s), mass of H20, initial temperature of the water, and final temperature of the solution
Explanation:
molar enthalpy of solution of KCl(s) is heat evolved or absorbed when one mole of KCl is dissolved in water to make pure solution . The heat evolved or absorbed can be calculated by the following relation.
Q = msΔt where m is mass of solution or water , s is specific heat and Δt is change in temperature of water .
So data required is mass of water or solution , initial and final temperature of solution , specific heat of water is known .
Now to know molar heat , we require mass of solute or KCl dissolved to know heat heat absorbed or evolved by dissolution of one mole of solute .
The balanced equation for the reaction is as follows
Cu₂O + 2HCl ---> 2CuCl + H₂O
Molar ratio of Cu₂O to CuCl is 1:2
mass of Cu₂O reacted - 73.5 g
Number of moles of Cu₂O reacted - 73.5 g / 143 g/mol = 0.51 mol
According to the molar ratio,
when 1 mol of Cu₂O reacts then 2 mol of CuCl is formed
therefore when 0.51 mol of Cu₂O reacts then - 2 x 0.51 mol of CuCl is formed
number of CuCl moles formed - 1.02 mol
mass of CuCl formed - 1.02 mol x 99 g/mol = 101 g
mass of CuCl formed is 101 g
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The atomic number is the same as the amount of electrons and protons. For example:
Oxygens atomic number is 8 so the proton and electron count is 8.
Hydrogens atomic number is 1 so the proton and electron count is 1.
Answer:
See explanation below
Explanation:
In this case, HCl is a strong acid, therefore, it dissociates completely in solution.
To know the quantity of water we need to add, we first need to know the concentration of the acid with pH = 6:
[H⁺] = antlog(-pH)
[H⁺] = antlog(-6) = 1x10⁻⁶ M
This means that the concentration is being diluted.
Now, even if we add great quantities of water, and the concentration and volume change, there is one time that do not change despite the quantity of water added; this is the moles. So, all we have to do, is calculate the moles of the acid in the 1 mL of water, and then, the volume of the acid when it's dilluted:
moles HCl = 0.1 * (1/1000) = 1x10⁻⁴ moles
Now that we have the moles, we can calculate the volume which the acid with the lowest concentration has:
V = mol/M
V = 1x10⁻⁴ / 1x10⁻⁶
V = 100 L
This means that we need to add 99.999 mL of water