Answer: The concentration of the OH-, CB = 0.473 M.
Explanation:
The balanced equation of reaction is:
2HCl + Ca(OH)2 ===> CaCl2 + 2H2O
Using titration equation of formula
CAVA/CBVB = NA/NB
Where NA is the number of mole of acid = 2 (from the balanced equation of reaction)
NB is the number of mole of base = 1 (from the balanced equation of reaction)
CA is the concentration of acid = 1M
CB is the concentration of base = to be calculated
VA is the volume of acid = 23.65 ml
VB is the volume of base = 25mL
Substituting
1×23.65/CB×25 = 2/1
Therefore CB =1×23.65×1/25×2
CB = 0.473 M.
Answer:
6.75 moles of CuCl₂ were used
Explanation:
Given data:
Number of moles of AlCl₃ formed = 4.5 mol
Number of moles of CuCl₂ used = ?
Solution:
Chemical equation:
3CuCl₂ + 2Al → 2AlCl₃ + 3Cu
Now we will compare the moles of CuCl₂ and AlCl₃
AlCl₃ : CuCl₂
2 : 3
4.5 : 3/2×4.5 = 6.75
6.75 moles of CuCl₂ were used.
Answer:
26.95 %
Explanation:
Air contains the highest percentage of oxygen and nitrogen gases. Magnesium then combines with both of the gases:


Firstly, find the total number of moles of magnesium metal:

Let's say that x mol react in the first reaction and y mol react in the second reaction. This means:

According to stoichiometry, we form:

Multiplying moles by the molar mass of each substance will yield mass. This means we form a total of:

The total mass is given, so we have our second equation to solve:

We have two unknowns and two equations, we may then solve:


Express y from the first equation:

Substitute into the second equation:





Moles of nitride formed:

Convert this to mass:

Find the percentage:
