Nitrous acid<span> dissociates as follows:
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HNO₂(s) ⇄ H⁺(aq) + NO₂⁻(aq)
According to the equation, an acid constant has the following form:
Ka = [H⁺] × [NO₂⁻ ] / [HNO₂]
From pH, we can calculate the concentration of H⁺ and NO₂⁻:
[H⁺] = 10^-pH = 10^-2.63 = 0.00234 M = [NO₂⁻]
Now, the acid constant can be calculated:
Ka = 0.00234 x 0.00234 / 0.015 = 3.66 x 10⁻⁴
And finally,
pKa = -log Ka = 3.44
<span>Methink this is a neutralization reaction where an acid reacts with a base to form salt and water; but if we must balance the equation, we need to know what the product would be?
So our base LiOH reacts with our acid Tetraoxosulphate (VI) H2SO4. The reaction produces salt and water as evidence. LiOH + H2SO4 gives Li2SO4 and H20. We need to make sure that the total atoms on the LHS and RHS balanced. So adding two moles of LiOH, we have 2LiOH + H2SO4 produces LiSO4 + H20. The eqn isn't balanced yet as there's 2 moles of deficit H2 atoms on the RHS,
So our final reaction we have 2LiOH + H2SO4 gives Li2SO4 + 2H2O. Hence our answer is C</span>
1 mol of any particles has 6.02 * 10 ²³ particles.
If we look at 1 NH3 (1 mol NH3 or 1 molecule NH3), we can see that 1 molecule NH3 has 1 atom of N and 3 atoms of H; also 1 mole of NH3 has 1 mole of N atoms and 3 moles of H atoms.
So, 1 mol of NH3 has 1 mol of N atoms,
and 2.79 mol NH3 have 2.79 mol of N atoms.
2.79 mol of N atoms* 6.02 * 10 ²³ N atoms/ 1 mol N atoms = 1.68*10²⁴ N-atoms
Answer is 1.68*10²⁴ N-atoms.
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Answer:

Explanation:
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In this case, taking into account that HCl has one molecule of hydrogen per mole of compound which weights 36.45 g/mol, we compute the number of molecules of hydrogen in hydrochloric acid by considering the given mass and the Avogadro's number:

Now, from the 180 g of water, we see two hydrogen molecules per molecule of water, thus, by also using the Avogadro's number we compute the molecules of hydrogen in water:

Thus, the total number of molecules turns out:

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