Answer:
554.86kj
Explanation: Since 1 mole of CaC2=15.14kj yield 1mole of C2H2
The enthalpy change of H2O is 2*285=570
570+-15.14=554.86kj
Hence Hp is 554.86kj
He=Hp
Answer:

Explanation:
Hello,
In this case, since the chemical reaction is:

We can see that hydrochloric acid and magnesium hydroxide are in a 2:1 mole ratio, which means that the neutralization point, we can write:

In such a way, the moles of magnesium hydroxide (molar mass 58.3 g/mol) in 500 mg are:

Next, since the pH of hydrochloric acid is 1.25, the concentration of H⁺ as well as the acid (strong acid) is:
![[H^+]=[HCl]=10^{-pH}=10^{-1.25}=0.0562M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BHCl%5D%3D10%5E%7B-pH%7D%3D10%5E%7B-1.25%7D%3D0.0562M)
Then, since the concentration and the volume define the moles, we can write:
![[HCl]*V_{HCl}=2*n_{Mg(OH)_2}](https://tex.z-dn.net/?f=%5BHCl%5D%2AV_%7BHCl%7D%3D2%2An_%7BMg%28OH%29_2%7D)
Therefore, the neutralized volume turns out:

Best regards.
Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years
Answer:
Explanation:
Oxyacids are acid containing oxygen; they are also known as acid-alcohol or acid-phenol. As said earlier, the strength of these acids increases with increases in the polarity of these compounds. So, what makes the polarity is as a result of the electronegative substituents attached to it. Halogen family possesses the highest electronegativity in the periodic table, and electronegativity decreases down the group.
The ranking of the oxyacids in order of decreasing acid strength from strongest to weakest acid is:
HClO3 > . HClO2 > HClO > HBrO
Given the mass of
=25.6 g
The molar mass of
=390.35g/mol
Converting mass of
to moles:

Converting mol
to mol S:

Converting mol S to atoms of S using Avogadro's number:
1 mol = 
