The valence level of an atom refers to the number of electrons that reside in the upper most energy level. Nitrogen has an atomic number of 7 and therefore has 7 electrons. The first energy level (1) holds 2 electrons, leaving 5 electrons to reside in the second energy level (2s and 2p). Therefore the valence of nitrogen is 5.
Answer:
Explanation:
20% of C2H6O2
since its a solution, this means that it has 20g of ethylene glycol and the rest is water.
Molar mass of C2H6O2 = (12 x 2) + (1 x 6) + (2 x 16)
= 62
mole = mass/molar mass
Moles of C2H6O2 = 20/62
= 0.322 mol
Moles of water = 80/18
= 4.444 mol
mole fraction = mol of solute / tatal mol of solution
Mole fraction of ethylene glycol = 0.322/(0.322 + 4.444)
= 0.068
Mole fraction of water = 1 - 0.068
= 0.932
Answer:
- C₃H₈ (g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (l)
(option D. with the proviso that the subscripts of propane's chemical formula must be corrected)
Explanation:
<em>Propane</em> is the saturated hydrocarbon, alkane, with chemical formula C₃H₈ or CH₃CH₂CH₃.
The complete combustion of the hydrocarbons yield carbon dioxide (CO₂) and water (H₂O).
The chemical equation that represents this combustion is:
- C₃H₈ (g) + O₂(g) → CO₂ (g) + H₂O (l) (skeleton equation: unbalanced)
Once you balance it, you get:
- C₃H₈ (g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (l)
Left side Right side
C 3 3
H 8 4×2 = 8
O 5×2 = 10 3×2 + 4 = 10
That equation corresponds to the option D. of the list, with the proviso that the subscripts of propane's chemical formula must be corrected
