Answer:
1)Na2O
let the valency of Na is x
2(x)+(2)=0
2x+2=0
2x=-2
x=-1
2)ZnO
let the valency of Zn is x
x+2=0
x=-2
3)Al2O3
let the valency of Al is x
2(x)+3(2)=0
2x+6=0
2x=-6
x=-3
4)MgO
let the valency of Mg is x
x+2=0
x=-2
Solid is the low energy state of condensed matter is characterized by structural rigidity
a) Answer:
= 210,000 gram or 210 Kg
Explanation:
14 hr is equivalent to;
= 14 × 3600 s
But;
8.2x10^4 A = 8.2x10^4 Coulomb /second = 8.2x10^4 C/s
1 Faraday = 96485C
Molar mass of Li: 6.941 g/mol
Therefore;
{(8.2x10^4 C/s)×(14×3600s)×(6.941 g/mol)/(96485C/mol)}×70%
= 2.1x10^5 gram or 210 kg
b. Answer;
= 0.23 kWh/mol
Explanation and solution;
Energy per mole is given by;
(96485C/mol) × (8.4V) = 8.10x10^5 (J/mol)
= 8.10x10^5 (Ws/mol)
Divide by 3600s/h to get:
= 8.10x10^5 (Ws/mol)
= 225 Wh/mol
= 0.23 kWh/mol
A prediction is not based upon evidence or reliable tests. A prediction is a guess as to what will happen in the future. Forecasts for example are nothing more than prediction, as even with "meteorological evidence", nothing is ever truly sure when in regard to wheather.
So "A"
Answer:
Different elements emit differently colors of light because when electrons return to the lower energy levels, they emit energy in a different form of light
Explanation: