Talking about ions, a cation has a positive charge. That means a positive charge is gained by an atom that gives out electrons.
Answer:
78.6 lb/ft³
Step-by-step explanation:
Let's do this in steps.
1. Convert grams to pounds
D = (1.26 g/1 cm³) × (1 lb/454 g)
= 2.775 × 10⁻³ lb/cm³
2. Convert cubic centimetres to cubic feet
D = (2.775 × 10⁻³ lb/1 cm³) × (28 317cm³/1 ft³)
= 78.6 lb/ft³
The Nernst equation is:
E = E° - RTlnK/nF
where
E° is the standard potential voltage
R is the universal gas constant = 8.314 J/mol·K
K is the reaction quotient
n is the number of moles electrons transferred
F is Faraday's constant = 96,500 C/mol e⁻
Let's determine K first. The overall reaction is:
Fe(s) + Cd²⁺(aq) --> Fe²⁺(aq) + Cd(s)
Accounting for aqueous phases only,
K = [products]/[reactants] = [Fe²⁺]/[Cd²⁺] = 0.10 M/1.4 M = 1/14
From the reactions written, you can see that 2 electrons were transferred. So, n = 2.
Lastly, the value for E⁰ is the sum of individual E⁰ of the reactions.
E⁰ = E⁰cathode - E⁰anode
Cathode reaction: Fe(s) --> 2e + Fe²⁺ (E⁰cathode = 0.44 V)
Anode reaction: Cd²⁺ + 2e --> Cd(s) (E⁰anode = -0.4 V)
Thus,
E⁰ = 0.44 - -0.4 = 0.84 V
Substituting the values (assume T at room temperature = 298 K),
E = 0.84 - (8.314)(298 K)(ln 1/14)/(2)(96,500)
<em>E = 0.87 V</em>
Answer:
The molarity of the solution is 0,12 M.
Explanation:
We calculate the molarity, which is a concentration measure that indicates the moles of solute (in this case KOH) in 1000ml of solution (1 liter):
0,25 L solution----- 0,030 moles of KOH
1 L solution----x= (1 L solution x 0,030 moles of KOH)/0,25 L solution
x= 0,12 moles of KOH ---> <em>The solution is 0,12 M</em>
