Answer:
0.80m of KOH
Explanation:
Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.
In the problem, the solute is KOH and solvent is water.
Moles of 36g KOH -Molar mass: 56.1g/mol- are:
36g KOH × (1mol / 56.1g) = <em>0.642 moles of KOH</em>
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Now, as density of water is 1g/mL, mass of 800mL of water is:
800mL × (1g / mL) × (1kg / 1000g) = <em>0.800kg of water</em>
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Thus, molality is:
0.642moles of KOH / 0.800kg = <em>0.80m of KOH</em>
In given data:
maximum absorption wavelength λ = 580 nm = 580 x 10⁻⁹ m
write the equation to find the crystal field splitting energy:
E = hC / λ
Here, E is the crystal field splitting energy, h = 6.63 x 10⁻³⁴ J.sec is Planck's constant and C = 3 x 10⁸ m/sec is speed of light.
substitute in the equation above:
E = (6.64 x 10⁻³⁴ x 3 x 10⁸) / (580 x 10⁻⁹) = 3.43 x 10⁻¹⁹J
This crystal field splitting energy is for 1 ion.
Number of atoms in one mole, NA = 6.023 x 10²³
to calculate the crystal field splitting energy for one mole:
E(total) = E x NA
= (3.43 x 10⁻¹⁹) x (6.023 x 10²³) = 206 kJ/ mole
MH₂CO₃: (1g×2) + 12g + (16g×3) = 62 g/mol
1 mol --- 62g
0,8 mol -- X
X = 0,8×62
X = 49,6g
Answer:
0.363g citric acid
Explanation:
Sodium hydroxide (NaOH) reacts with acids, thus:
NaOH + H⁺ → H₂O + Na⁺
The volume of titration is:
18.39mL - 0.73mL = 17.66mL
Moles of this volume in 0.107M NaOH are:
0.01766L × (0.107 mol / L) = 0.00189mol NaOH ≡ mol citric acid<em> -Assuming the only acid in pear juice is citric acid-</em>
As molar mass of citric acid is 192.124g/mol:, Mass of citric acid is:
0.00189mol citric acid × (192.124g / mol) = <em>0.363g citric acid</em>
I hope it helps!
