Question:
What's the article about?
Answer: 0.004 moles
Explanation:
Amount of substance= mass/ molar mass
Mass= 250mg or 0.25g
Molar mass= 58.44gmol-1
Amount= 0.25/58.44
= 0.004 moles
Unfortunately you did not specify the electronic configuration in the question, however since one of the answers must be a halogen, i took the liberty to attach an image with the configuration (both the simple numeric and spdf form) for all the halogen and all you have to do is match the electronic configuration you have in your question to the one in the table attached and you can then deduce the answer.
Hope this helps.
Answer:
Correct choice are C and D (they are both, the same).
Explanation:
Cathode is the positive(+) electrode where a reduction occurs.
Reduction is the chemical reaction where the oxidation state is reduced.
2Ag(s) + 1/2 O2(g) + 2H+(aq) → 2Ag+(aq) + H2O (l)
A. 2H2O (l) → O2 (g) + 4H+ (aq) + 4e-
B. 2Ag (s) → 2Ag+ (aq) + 2e-
C. 1/2 O2 (g) + 2H+ (aq) + 2e- → H2O (l)
D. 1/2 O2 (g) + 2H+ (aq) + 2e- → H2O (l)
C or D, are ok. They are the same equation.
Oxygen from ground state reduce the oxidation state from 0 to -2
We can use the ideal gas
equation which is expressed as PV = nRT. At a constant pressure and number of
moles of the gas the ratio T/V is equal to some constant. At another set of
condition of temperature, the constant is still the same. Calculations are as
follows:
T1 / V1 = T2 / V2
V2 = T2 x V1 / T1
V2 = 303.15 x 300 / 333.15
<span>V2 = 272.99 cm³</span>
