Answer:
(C) O, C, H, N
Explanation:
<u>Roughly 96% of mass of human body is made up of four elements which are oxygen, carbon, nitrogen and hydrogen.</u>
Oxygen and hydrogen are predominantly found in the water, which makes up about 60% of body's weight. Carbon is synonymous with the life. The central role of carbon is due to fact that it has four bonding sites which allow for building of long and complex chains of the molecules. Moreover, these carbon bonds can be formed and also be broken with amount of energy which makes life alive. Nitrogen is found in organic molecules, including amino acids which make up the proteins, and nucleic acids which make up the DNA.
Explanation:
Moles of phosphorus pentachloride present initially = 2.5 mol
Moles of phosphorus trichloride at equilibrium = 0.338 mol
Initially
2.5 mol 0 0
At equilibrium:
(2.5 - x) mol x x
So, from above, the moles of phosphorus trichloride at equilibrium , x= 0.338 mol
Mass of 0.338 moles of phosphorus trichloride at equilibrium:
= 0.338 mol × 137.5 g/mol = 46.475 g
Moles of phosphorus pentachloride present at equilibrium :
= (2.5 - 0.338) mol = 2.162 mol
Mass of 2.162 moles of phosphorus pentachloride at equilibrium:
= 2.162 mol × 208.5 g/mol = 450.777 g
Moles of chloride gas present at equilibrium : 0.338 mol
Mass of 0.338 moles of chloride gas at equilibrium:
= 0.338 mol × 71 g/mol = 23.998 g
Answer:
Option (2) 2
Explanation:
NO3- + 4H+ + Pb → Pb2+ + NO2 + 2H2O
The equation above can be balance as follow:
There are 3 atoms of the left side and a total of 4 atoms on the right side. It can be balance by putting 2 in front NO3- and 2 in front of NO2 as shown below:
2NO3- + 4H+ + Pb → Pb2+ + 2NO2 + 2H2O
Now the equation is balanced.
The coefficient of NO2 is 2
The concentration of Ca2+ ions is half that of the Cl- ions.
