Answer:
(A) 0.129 M
(B) 0.237 M
Explanation:
(A) The reaction between potassium hydrogen phthalate and barium hydroxide is:
- 2HA + Ba(OH)₂ → BaA₂ + 2H₂O
Where A⁻ is the respective anion of the monoprotic acid (KC₈H₄O₄⁻).
We <u>convert mass of phthalate to moles</u>, using its molar mass:
- 0.978 g ÷ 156 g/mol = 9.27x10⁻³ mol = 9.27 mmol
Now we <u>convert mmol of HA to mmol of Ba(OH)₂</u>:
- 9.27 mmol HA *
= 6.64 mmol Ba(OH)₂
Finally we calculate the molarity of the Ba(OH)₂ solution:
- 6.64 mmol / 35.8 mL = 0.129 M
(B) The reaction between Ba(OH)₂ and HCl is:
- 2HCl + Ba(OH)₂ → BaCl₂ + 2H₂O
So<u> the moles of HCl that reacted </u>are:
- 17.1 mL * 0.129 M *
= 4.41 mmol HCl
And the <u>molarity of the HCl solution is</u>:
- 4.41 mmol / 18.6 mL = 0.237 M
Answer:
397 g
Explanation:
From the information given in the question ,
the atomic mass of X = 12 ,
and , the atomic mass of Y = 1 .
For the molecular formula , X₇Y₁₁ , the molecular mass is given as -
X₇Y₁₁ = 7 * atomic mass of X + 11 * atomic mass of Y
= 7 * 12 + 11 * 1
= 84 + 11 = 95 g / mol
Hence , molecular mass of X₇Y₁₁ = 95 g / mol .
Moles is denoted by given mass divided by the molecular mass ,
Hence ,
n = w / m
n = moles ,
w = given mass ,
m = molecular mass .
From question ,
moles n = 4.18 mol
and ,
m = molecular mass of X₇Y₁₁ = 95 g / mol .
To find the mass of the compound X₇Y₁₁ , the above formula can be used , and putting the respective values ,
n = w / m
4.18 = w / 95
w = 4.18 * 95 = 397 g
John Dalton is considered the father of the atomic theory. In 1800s he had came up with 5 concepts regarding the atomic theory.
Hope I helped.
Can't say i can answer this. :/
