Answer:
The mass percent of Al(OH)₃ is 15.3%
Explanation:
The reaction is:
Al(OH)₃ + 3HCl = AlCl₃ + 3H₂O
The excess acid is neutralized with a solution of sodium hidroxide, in the reaction:
NaOH + HCl = NaCl + H₂O
The total moles of HCl is:

From the second titration, the moles of excess of HCl is:

The difference between the total and excess of HCl, it can be know the moles that reacts with the aluminum hydroxide, is:

The ratio between HCl and Al(OH)₃ is 3:1. The MW for aluminum hydroxide is 78 g/mol, thus:

The percentage of Al(OH)₃ is:
%
Answer:
375.2 kJ
Explanation:
- H₂(g) +F₂(g) → 2HF(g) +536kJ
The information the equation above provides lets us know that when 2 mol of hydrogen fluoride (HF) are produced, 536 kJ of energy (as heat) is produced.
We can then <u>state a rule of three</u>:
And <u>solve for X</u>:
- X = 1.4 mol * 536 kJ / 2 mol
Answer: This is because the number of shell increases .
Explanation: On moving from left to write on the periodic table the reactivity of non metals increases because number of shells increases and the force with which the nucleus hold electrons decreases.