Answer:
Pressure for H₂ = 11.9 atm
Option 5.
Explanation:
We determine the complete reaction:
2Al(s) + 6HCl(aq) → 2AlCl₃(aq) + 3H₂(g)
As we do not know anything about the HCl, we assume that the limiting reactant is the Al and the acid is the excess reagent.
Ratio is 2:3.
2 moles of Al, can produce 3 moles of hydrogen
Therefore 4.5 moles of Al must produce (4.5 . 3) / 2 = 6.75 moles
Now we can apply the Ideal Gases law to find the H₂'s pressure
P . V = n . R . T → P = (n . R .T) / V
We replace data: (6.75 mol . 0.082L.atm/mol.K . 300K) / 14L
Pressure for H₂ = 11.9 atm
Answer:
pH = 12.7
Explanation:
First, we have to calculate the [Ca²⁺] in a solution of about 250 ppm CaCO₃.
Now, let's consider the dissolution of Ca(OH)₂ in water.
Ca(OH)₂(s) ⇄ Ca²⁺(aq) + 2 OH⁻(aq)
The solubility product Ksp is:
Ksp = [Ca²⁺] × [OH⁻]²
[OH⁻] = √(Ksp/[Ca²⁺]) = √(6.5 × 10⁻⁶/2.5 × 10⁻³) = 5.1 × 10⁻² M
Finally, we can calculate pOH and pH.
pOH = -log [OH⁻] = -log (5.1 × 10⁻²) = 1.3
pH + pOH = 14 ⇒ pH = 14 - pOH = 14 - 1.3 = 12.7
Answer:
0.034 mol (4dp)
Explanation:
Use the formula n = m/M where n= number of moles, m=mass in grams and M=molar mass in g/mol.
Therefore to find how many moles, divide the mass in grams (2) by the molar mass of sodium chloride which is 22.99+35.45
Hydrogen is the only element in entire periodic table with only 1 proton in its nucleus.
