Answer:
Buffers are resistant to high pH changes.
Explanation:
This perfectly explains the reason why we use buffers. Buffers are substances which consist of a weak acid and its conjugate base. Buffers are resistant to significant pH changes upon addition of strong acids or bases. To illustrate this, let's say we have a buffer consisting of 0.1 mol of HF, a weak acid, and 0.1 mol of NaF (fluoride is a conjugate base of HF).
- Let's say we add some strong acid, in a general form, this acid would be represented as . In this case, conjugate base will react and neutralize it to produce some amount of HF: .
- Similarly, if we add some strong base , the acidic component will react with it to produce some amount of conjugate base: . The ratio of HF to NaF in this case is held around the same value for addition of small amounts of strong acids/bases, so pH is kept almost constant, while in neutral water, pH would drastically increase or decrease.
Answer 328.1k J
Explanation :
Answer:
41.9(w/w) %
Explanation:
Based on the reaction:
Na₂C₂O₄(s) + 2HCl(aq) → H₂C₂O₄(aq) + 2NaCl(aq)
<em>Where 1 mole of sodium oxalate reacts with 2 moles of HCl</em>
Moles of HCl solution to reach end point are:
44.15mL = 0.04415L ₓ (0.250mol / L) = 0.01104 moles of HCl
As 2 moles of HCl reacts per mole of Na₂C₂O₄:
0.01104mol HCl ₓ (1 mol Na₂C₂O₄ / 2 mol HCl) = <em>5.519x10⁻³ moles Na₂C₂O₄</em> are in the sample.
Molar mass of Na₂C₂O₄ is 134g/mol; thus, mass of 5.519x10⁻³ moles Na₂C₂O₄ is:
5.519x10⁻³ moles Na₂C₂O₄ ₓ (134g / mol) = <em>0.740g of Na₂C₂O₄</em> in the sample.
Thus, percent by mass of sodium oxalate in the sample is:
0.740g of Na₂C₂O₄ / 1.766g ₓ 100 =
<h3>41.9(w/w) %</h3>
Answer:
glucosa
En la fotosíntesis, la energía solar se recolecta y se convierte en energía química en forma de glucosa utilizando agua y dióxido de carbono. El oxígeno se libera como subproducto.
Explanation:
H^+ S^-2 -> H2S - Chemical formula of Dihydrogen monosulphide.
Electron Dot Diagram
•• ••
H • •S• •H -> H-S-H
•• ••