Formula for Molarity is given as,
Molarity = moles / Volume of Solution in L ----(1)
Also,
Moles = mass / M.mass
Putting value of mole in eq. 1,
Molarity = (mass / M.mass) / Vol
Solving for mass,
Mass = Molarity × M.mass × Vol
Putting Values,
Mass = 0.15 mol/L × 40 g/mol × 0.5 L
Mass = 3 g
Result:
Weight 3 g of NaOH, add it to a 500 ml volumetric flask, and add distilled water to the point of 500 ml. The resulting solution will be 0.15 M.
Explanation:
Knowing the pH, you know the concentration of protons:
−log[H+]=pH=3.7
[H+]=10−3.7 M
Now, since the weak (monoprotic) acid dissociates into its conjugate base and a proton, the mols of protons are equimolar with the mols of conjugate base---the protons came FROM the weak acid, so the conjugate base that forms must be equimolar with the protons given out to the solvent.
HA⇌A−+H+
Hence, [A−]=[H+] in the same solution volume. Using the equilibrium constant expression, we get:
Ka=[H+]2eq[HA]eq
Don't forget that the HA form of HA had given away protons, so the mols of protons given away to generate A− is subtracted from the mols of (protons in) HA.
=[H+]2eq[HA]i−[H+]eq
=(10−3.7M)20.02M−10−3.7M
Ka=2.0105×10−6 M
I think your answer choices are...
A. an educated guess
B. a statement of pure fact
C. a general principle based on an observable fact
D. a collection of data
Answer:
C. A general principle based on an observable fact
Explanation:
It can't be A as an educated guess is in scientific terms , a hypothesis.
It can't be B as that is a fact or a law
It can't be D as a collection of data is a data table.
Answer:
T₂ = 687.6 K
Explanation:
Given data:
Initial pressure = 108 Kpa = 108/101 = 1.06588 atm
Initial temperature = 20°C = 20+273.15 = 293.15 k
Final temperature = ?
Final pressure = 2.50 atm
Solution:
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
Now we will put the values in formula:
1.06588 atm / 293.15 K = 2.5 atm/T₂
T₂ = 2.5 atm ×293.15 K / 1.06588 atm
T₂ = 732.875 atm. K /1.06588 atm
T₂ = 687.6 K
Answer:
The effect is the increasing of the molar concentration.
Explanation:
When you standarize a solution of NaOH with KHP you are establish its molar concentration (That is the amount of moles of NaOH per liter of solution).
If you evaporated some water of the solution, you are increasing its concentration because volume is decreasing doing the amount of moles per liter increasing.