Answer:
0.46 V
Explanation:
The emf for the cell is given by:
Eº cell = Eº oxidation + Eº reduction
From the given balanced chemical equation, we can deduce that Fe²⁺ has been oxidized to Fe³⁺, and O reduced from 0 to negative 2, according to the half cell reactions:
4Fe²⁺ ⇒ Fe³⁺ + 4e⁻ oxidation
O₂ + 4H⁺ + 4 e⁻ ⇒ 2 H₂O reduction
From reference tables for the standard reduction potential, we get
Eº red Fe³⁺ / Fe²⁺ Eºred = 0.77 V
Eº red O₂ / H₂O Eºred = 1.23 V
Now all we need to do is change the sign of Eº reduction for the species being oxidized ( Fe²⁺ ) and add it to Eº reduction O₂:
Eº cell = Eº oxidation + Eº reduction = - (0.77 V ) + 1.23 V = 0.46 V
Answer:Gases and solids , Solids and liquids
Explanation:
A solid has a definite shape while liquids and gases take the shape of the container in which they are found .
Hence when a substance changes it's state from gas to solid or solid to liquid, it's shape automatically changes as explained above.
It's just H20 but with 3 water molecules
Answer:
70.0 %
Explanation:
Step 1: Given data
- Mass of nitrogen (mN): 74.66 g
- Mass of the compound (mNxOy): 250 g
Step 2: Calculate the mass of oxygen (mO) in the compound
The mass of the compound is equal to the sum of the masses of the elements that form it.
mNxOy = mN + mO
mO = mNxOy - mN
mO = 250 g - 74.66 g = 175 g
Step 3: Determine the percent composition of oxygen in the sample
We will use the following expression.
%O = mO / mNxOy × 100%
%O = 175 g / 250 g × 100% = 70.0 %
Given data:
Distance travelled (d)= 200.0 m
Time taken (t) = 21.7 s
To determine:
The average speed in km/hr
Calculation:
Convert distance from m to km
1000 m = 1 km
200.0 m = 1 km * 200.0 m/1000 m = 0.2 km
Convert time from sec to hours
3600 sec = 1 hour
21.7 sec = 1 hour * 21.7 sec/3600 sec = 6.027 *10^-3 hrs
Speed is defined as the amount of distance travelled per unit time
Speed = distance/time = 0.2 km/6.027*10^-3 hr
= 33.18 km/hr (or 33.2 km/hr)
