Half reaction: Cr₂O₇²⁻(aq) + 7H₂O(l) + 6e⁻ → 2Cr³⁺(aq) + 14OH⁻(aq).
Chromium change oxidation number from +6 in dichromate ion Cr₂O₇²⁻ to +3 in chromium cation.
Sum of the charges on the left side of the half reaction is -2 and on the left side is -8 (2·(+3) +14·(-1)), so six electrons must be added on the left side of half reaction.
1. Increasing
2. Increasing
3. Decreasing
4. Increasing
5. Decreasing
49 neutrons in each nucleus.
<h3>Explanation</h3>
For each nucleus:
Mass number = Number of protons + Number of neutrons.
The atomic number of a nucleus is the same as its number of protons. The atomic number of the nucleus here is 31. There are 31 protons in each nucleus.
- Mass number = 80;
- Number of protons = Atomic number = 31;
- The number of neutrons is to be found.
Again,
Mass number = Number of protons + Number of neutrons.
80 = 31 + Number of neutrons.
Number of neutrons = 80 - 31 = 49.
Answer:
1.2×10²³ atoms.
Explanation:
Data obtained from the question include:
Mole of propanone = 0.20 mole
Number of atoms of propanone =.?
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms.
This implies that 1 mole of propanone also contains 6.022×10²³ atoms.
Thus, we can obtain the number of atoms in 0.20 mole of propanone as illustrated below:
1 mole of propanone contains 6.022×10²³ atoms.
Therefore, 0.20 mole of propanone will contain = 0.2 × 6.022×10²³ = 1.2×10²³ atoms.
Thus, 0.20 mole of propanone contain
1.2×10²³ atoms.
