<span>The answer to this question would be: B. a solid that forms when two liquids are mixed
Precipitation is creating a solid substance from the solution. The product is called precipitate and the solution would be called supernate. Precipitation could happen because of gravity pulling up the molecule or because the molecule is saturated.</span>
We let the chemical equation for the weak acid indicator propyl red HPr be
HPr + H2O ↔ H3O+ + Pr-
Therefore, the acid dissociation constant Ka is
Ka = [H3O+][Pr-] / [HPr]
The color of this indicator turns from red to yellow or the other way around at its turning point at which
[HPr] = [Pr-]
Substituting this to the equation for Ka, we now have
Ka = [H3O+]
The pH of the solution at its turning point is
pH = -log[H3O+] = -log(Ka) = -log 3.3×10^-6 = 5.48
<span>On this account, the pH range is pH 5.0 to 6.0.</span>
At STP, P = 1 atm, and T = 0 C
Thus, PV = nRT => V = nR(273). We will use this later...
if you have 35.4 Ca, and the molar mass of Ca is 40.08, you get .883 moles Ca. Thus, since it takes 2 moles of Ca to form a reaction, you only need half the moles of Ca of O2. Thus, n(O2) = .883/2
Tie this back to the first equation and you get
V = .442 * <span>0.082057(which is R) * 273 = 9.9 L</span>
To find the number of neutrons.....
NEUTRONS = MASS NUMBER - ATOMIC NUMBER ( PROTONS)
NEUTRONS = 19 - 9
So this element has 10 neutrons