This problem is asking for the percent by mass of hydrogen in hydrofluoric acid. At the end, the answer turns out to be D. 5% as shown below:
<h3>Percent compositions:</h3>
In chemistry, percent compositions are used for us to know the relative amount of a specific element in a compound. In order to do so for hydrogen, we use the following formula, which can also be applied to any other element in a given compound:
Where 
stands for the atomic mass of hydrogen and 
for the molar mass of hydrofluoric acid. In such a way, we plug in the atomic masses of hydrogen (1.01 g/mol) and fluorine (19.0 g/mol) to obtain:
Learn more about percent compositions: brainly.com/question/12247957
Answer:
41.44 g
Explanation:
First of all, we must put down the equation of the reaction;
Number of moles of CaO = 33g/56 g/mol = 0.59 moles
Number of moles of H20 = 10g/18 g/mol = 0.56 moles
Since the reaction is in 1:1 mole ration, H2O is the limiting reactant
Hence;
mass of Ca(OH)2 produced = 0.56 moles * 74 g/mol = 41.44 g
Answer:
The symbol of the ion is A^-
Explanation:
Let A be the symbol of the element.
Proton = 17
Electron = 18
Neutron = 20
Since the element has more electrons than protons, it means it has gain electrons.
From the question given,
The difference between the electron and proton = 18 — 17 = 1
So, the element has gain 1 electron.
Therefore the symbol of the ion is A^-
B) O^2-
Hope this helped :)
