According to this formula :
ΔTf= i Kf m
i is van't Hoff factor= 1
Kf = 1.86
m the molality we need to assume it
m= x moles of C2H5OH / Kg of mass
∴ 15 = 1 * 1.86 * ( x moles of C2H5OH/ 0.45 kg)
∴X = 3.629 moles
mass = no.of moles x molar mass of C2H5OH
= 3.629 X 46 = 167 g
∴the volume = mass / denisty
= 167 / 0.7893 = 211.57≈ 212 mL
I think it looks good but some grammars are wrong i suggest trying to put it on grammarly and just check it out its just my suggestion and not doing this for points so you can delete this if it doesnt help
<em><u>Dinitrogen Tetraoxide</u></em>
Formula: N₂O₄
Molar mass: 92.011 g/mol
M = n/V
M = 1.51
V = 0.730
1.51 = n/0.730
To solve this, multiply both sides by the V.
1.1023 = n
n = 1.1023 mol
Answer:
6,45mmol/L of NaOH you need to add to reach this pH.
Explanation:
CH₃COOH ⇄ CH₃COO⁻ + H⁺ <em>pka = 4,74</em>
Henderson-Hasselbalch equation for acetate buffer is:
5,0 = 4,74 + log₁₀![\frac{[CH_{3}COO^-]}{[CH_{3}COOH]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BCH_%7B3%7DCOO%5E-%5D%7D%7B%5BCH_%7B3%7DCOOH%5D%7D)
Solving:
1,82 =
<em>(1)</em>
As total concentration of acetate buffer is:
10 mM = [CH₃COOH] + [CH₃COO⁻] <em>(2)</em>
Replacing (2) in (1)
<em>[CH₃COOH] = 3,55 mM</em>
And
<em>[CH₃COO⁻] = 6,45 mM</em>
Knowing that:
<em>CH₃COOH + NaOH → CH₃COO⁻ + Na⁺ + H₂O</em>
Having in the first 10mmol/L of CH₃COOH, you need to add <em>6,45 mmol/L of NaOH. </em>to obtain in the last 6,45mmol/L of CH₃COO⁻ and 3,55mmol/L of CH₃<em>COOH </em>.
I hope it helps!