Buffer solution resist the change in pH upon addition of small amount of strong acid or strong base.
Buffer consists of weak acid as HF / and its conjugate base NaF
When strong acid as HCl is added to buffer, it respond with its conjugate base to convert the strong acid to weak acid like this:
HCl (S.A) + NaF → NaCl + HF (W.A)
moles of HF we already have = M * V(in liters)
= 0.0955 M * 0.033 L = 3.15 x 10⁻³ mole
moles of HCl added = 8.00 x 10⁻⁵ mole
one mole HCl reacts with 1 mole NaF to give 1 mole HF
so the amount added to HF = 8.00 x 10⁻⁵
Total moles of HF present = (3.15 x 10⁻³) + (8.00 x 10⁻⁵) = 3.23 x 10⁻³ mole

4 0

3 years ago

What is the electron configuration of the element in group 13 and period 3 on the periodic table? *

tankabanditka [31]

Answer:

The 3rd option is correct

Explanation:

The element in group 13 and period 3 is aluminium which has the electron configuration

$1{s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{1}$

or [Ne] 3s^2 3p^1

4 0

2 years ago

C2H5OH( l) + 3O2( g) → 2CO2( g) + 3H2O( l); Δ H = –1.37 × 103 kJ Consider the following propositions: I. The reaction is endothe

Svetlanka [38]

Answer:

II. The reaction is exothermic.

III. The enthalpy term would be different if the water formed was gaseous.

Explanation:

For the reaction:

C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)

The ΔH is -1.37×10³ kJ. As the change in enthalpy is <0, II. The reaction is exothermic.

The ΔH formation of a compound is different if the chemical is in liquid or gaseous phase. For that reason: III. The enthalpy term would be different if the water formed was gaseous.

I hope it helps!

3 0

3 years ago