(a)
Write the balanced half-reactions for the overall process:
Oxidation: Se^2- (aq) → Se
(s) + 2e-
Reduction: 2So3^2- (aq) + 3H2O (l) + 4e- →
S2O3^2- + 6OH- (aq)
(b)
Assuming E sulfite is 0.57 V, compute E selenium:
E anode = E cathode – E cell
= -0.57 – 0.35
=
-.092
5060 has three significant figures: Below is the clarification
Explanation:
Significant figures
Significant figures (also referred to as significant digits and decimal places) in a number are those digits that carry substantial meaning.
These include all digits except: leading zeros.
Guidelines for determining significant figures
1. All non-zero digits are counted as significant. For instance, the number 23 has two significant figures.
2. Zeros located between two non-zero digits are significant; for example, 202.1201 contains seven significant figures.
3. Zeros preceding the significant figures are not significant. For example,.000021 has two significant figures, with zeros being non-contributory.
4. Zeros following the significant figures are significant.
This explains why the number 5060 has three significant figures.
Noble gas notation serves as a condensed form of indicating electron configurations. This notation employs the symbol for the preceding noble gas in the electron configuration of an element. For antimony, the noble gas prior is Kr, which means Xe is not used in its electron configuration. Similarly, for radium, the prior noble gas is Rn, whereas, for uranium, it is also Rn. However, for cesium, the preceding noble gas is Xe, thus it is utilized in the noble gas notation for Sb, specifically written as: Cs: [Xe] 6s.
Answer: cesium
Answer:6.94
Explanation:Atomic mass of Li = 6.94
To find the number of atoms: 12.6 g Li x 1 mole/6.94 g x 6.02x10^23 atom/mole = 1.09x10^24 atoms
The negative sign indicates that heat is released.
