Answer:
(i) Bohr; (ii) de Broglie; (iii) Heisenberg (v) Schrödinger
Explanation:
(i) Niels Bohr — 1913 — proposed that electrons travel in fixed orbits with <em>quantized energy levels</em> and that they jump from one energy level to another by absorbing or emitting quanta of light.
(ii) <em>Louis de Broglie</em> — 1924 — proposed the wave nature of electrons and suggested that all matter behaves as both waves and particles (<em>wave-particle duality</em>).
(iii) Werner Heisenberg — 1927 — formulated quantum mechanics in terms of matrices and proposed his famous <em>uncertainty principle</em>.
(v) Erwin Schrödinger — 1926 — applied wave mechanics to the electron in a hydrogen atom, showing that electrons exist in <em>orbitals </em>rather that orbits.
(iv) <em>Ernest Rutherford</em> — 1911 — proposed that atoms have most of their mass in a central nucleus (<em>nuclear atom</em>). Quantum mechanics had not yet been invented.
Answer:
0.2788 M
1.674 %(m/V)
Explanation:
Step 1: Write the balanced equation
NaOH + CH₃COOH → CH₃COONa + H₂O
Step 2: Calculate the reacting moles of NaOH

Step 3: Calculate the reacting moles of CH₃COOH
The molar ratio of NaOH to CH₃COOH is 1:1.

Step 4: Calculate the molarity of the acetic acid solution

Step 5: Calculate the mass of acetic acid
The molar mass of acetic acid is 60.05 g/mol.

Step 6: Calculate the percentage of acetic acid in the solution

This is your answer I hope it is right.
Answer:
.
Explanation:
Consider the oxidation state on each of the element:
Left-hand side:
- O: -2 (as in most compounds);
- Cr:
; - Fe: +2 (from the charge of the ion);
Right-hand side:
Change in oxidation state:
- Each Cr atom: decreases by 3 (reduction).
- Each Fe atom: increases by 1 (oxidation).
Changes in oxidation states shall balance each other in redox reactions. Thus, for each Cr atom on the left-hand side, there need to be three Fe atoms.
Assume that the coefficient of the most complex species
is 1. There will be two Cr atoms and hence six Fe atoms on the left-hand side. Additionally, there are going to be seven O atoms.
Atoms are conserved in chemical reactions. As a result, the right-hand side of this equation will contain
- two Cr atoms,
- six Fe atoms, and
- seven O atoms.
O atoms seldom appear among the products in acidic environments; they rapidly combine with
ions to produce water
. Seven O atoms will make seven water molecules. That's fourteen H atoms and hence fourteen
ions on the product side of this equation. Hence the balanced equation. Double check to ensure that the charges on the ions also balance.
.