Answer:
198.8mL
Explanation:
Step 1:
Data obtained from the question:
Molarity of base (Mb) = 3.5M
Volume of base (Vb) =..?
Molarity of acid (Va) = 2.75M
Volume of acid (Va) = 253mL
Step 2:
The balanced equation for the reaction.
HF + LiOH —> LiF + H2O
From the balanced equation above,
The mole ratio of the acid (nA) = 1
The mole ratio of the base (nB) = 1
Step 3:
Determination of the volume of the base, LiOH needed for the reaction.
The volume of the base needed for the reaction can be obtained as follow:
MaVa /MbVb = nA/nB
2.75 x 253 / 3.5 x Vb = 1
Cross multiply
3.5 x Vb = 2.75 x 253
Divide both side by 3.5
Vb = 2.75 x 253 / 3.5
Vb = 198.8mL
Therefore, the volume of the base needed for the reaction is 198.8mL
134.56 grams are 2.50 * 10^23 molecules of CaO.
Explanation:
According to Avagadro hypothesis, 1 mole of a substance contain 6.023 x 10^23 molecules or particles.
Data given:
Number of molecules of CaO =
FORMULA USED IN CALCULATION:
number of molecules = 6.02 x 10^23 x number of moles of CaO
At first number of moles is calculated:
= 2.4 moles of CaO is present
to calculate the mass of CaO in grams formula used is
mass = atomic mass x number of moles
atomic mass of CaO = 56.07 grams/mole
mass = 2.4 x 56.07
= 134.56 grams of calcium oxide is present is 2.50 * 10^23 molecules of CaO.
If the hydrogen ion concentration of a solution is 10–10M, is the solution is definitely alkaline. The thing I used to determine that fact is a basic point - pH above 7 is always alkaline, and as a proof, we can see from the task that the concentration of hydroxyl OH- is pretty higher than hydrogen H+, which is a direct characteristic of the alkain solution.Here is a tip for you, I bet it will be useful : >7 = basic <7 = acidic 7 = neutral
Answer: Think and you will get it right!
Explanation:
To find the mass percent composition of an element, divide the mass contribution of the element by the total molecular mass. This number must then be multiplied by 100% to be expressed as a percent.
