Its period 5 from 5s25p6, with Xenon(54) as the noble gas. 2+6 = 8 electrons
54+8 = 62, or Sm.
The molecules of hydrogen gas that are formed is when 48.7 g of sodium are added to water is 6.375 x 10²³ molecules
<u><em>calculation</em></u>
2 Na +2H₂O → 2 NaOH +H₂
Step 1: find the moles of sodium (Na)
moles =mass÷ molar mass
from periodic table the molar mass of Na = 23 g/mol
moles= 48.7 g÷ 23 g/mol =2.117 moles
Step 2:use the mole ratio to determine the moles of H₂
from given equation Na:H₂ is 2:1
therefore the moles of H₂ = 2.117 moles x 1/2=1.059 moles
Step 3: find the molecules of H₂ using the Avogadro's law
According to Avogadro's law 1 mole = 6.02 x 10²³ molecules
1.059 moles = ? molecules
by cross multiplication
= [(1.059 moles x 6.02 x10²³ molecules) / 1 mole] =6.375 x 10²³ molecules
B - Evolve into the closest species on the tree’s trunk
Answer:
0.534
Explanation:
Mole fraction can be calculated using the formula:
Mole fraction = number of moles of solute ÷ number of moles of solvent and solute (solution).
In this question, solute is dimethyl ether while the solvent is methanol.
Mole (n) = mass (M) ÷ molar mass (MM)
Mole of solute (dimethyl ether) = 148.5 ÷ 46.07
= 3.22moles.
Mole of solvent (methanol) = 90 ÷ 32.04
= 2.81moles.
Total moles of solute and solvent = 3.22 + 2.81 = 6.03moles.
Mole fraction of dimethyl ether = number of moles of dimethyl ether ÷ number of moles of solution (dimethyl ether + methanol)
Mole fraction = 3.22/6.03
= 0.534
