Answer is: pH of solution is 3,02.
c(benzoic acid) = 0,03 mol/dm³.
c(sodium benzoate) = 0,02 mol/dm³.
pKa(benzoik acid) = 3,19.
pH = ?
Henderson–Hasselbalch equation for buffers: pH = pKa + log(cs/ck)
pH = 3,19 + log(0,02/0,03)
pH = 3,19 - 0,176
pH = 3,02.
cs - concentration of acid.
Answer:
igneous or metamorphic
Explanation:
Those two are sorta relvant
Answer:
3.90 L
Explanation:
The reaction between NH₄I and Pb(NO₃)₂ is a double replacement reaction, so, the ions will dissociate and change in the two substances. The ions are NH₄⁺, I⁻, Pb⁺², and NO₃⁻, so the reaction is:
2NH₄I + Pb(NO₃)₂ → PbI₂ + 2NH₄NO₃
Thus, by the stoichiometry of the reactions, 2 moles of NH₄I are necessary to react with 1 mol of Pb(NO₃)₂. According to Proust's law, the proportion of the reaction must be kept so:
2 moles/1 mol = n NH₄I/n Pb(NO₃)₂
The number of moles of Pb(NO₃)₂ that will react is the concentration multiplied by the volume in L, so:
n Pb(NO₃)₂ = 0.280 * 0.905 = 0.2534 mol
2/1 = n NH₄I/0.2534
n NH₄I = 0.5068 mol
The volume of NH₄I is:
n NH₄I = 0.130 *V
0.5068 = 0.130V
V = 3.90 L
The location where the mercury level of the barometer would be the lowest is at the very high altitudes of the Earth's atmosphere (about 100 km), since air pressure decreases as altitude increases. Hope my answer has come to your help.