Answer:
- <em>The vapor pressure of the solution at 25°C is </em><u><em>23.6 mmHg</em></u>
Explanation:
<u>1) Data:</u>
- Mass of solute, sucroese, m₁ = 40.0 g
- Mass of solvent, water, m₂ = 250. g
- Vapor pressure of solution, p = ?
- Vapor pressure of pure water, p⁰ = 23.76 mm Hg
<u>2) Principles and formulae:</u>
- Raoult's law states that the vapor pressure of a solution is equal to the mole fraction of the solvent times the vapor pressure of the pure liquid.
p = X p⁰
<u>3) Solution:</u>
a) <u>Mole fraction of the solvent (water)</u>
- X = number of moles of solvent / number of moles of solution
- number of moles of solvent, n₁ = mass in grams / molar mass
n₁ = 250. g / 18.015 g/mol = 13.88 moles
- number of moles of solute, n₂ = mass in grams / molar mass
n₂ = 40.0 g / 342,3 g/mol = 0.12 moles
- total number of moles, n₁ + n₂ = 13.88 moles + 0.12 moles = 14.0 moles
- moles fraction of water, X = 13.88 moles / 14.0 moles = 0.99
b) <u>Vapor pressure of the solution</u>:
- p = p⁰ X = 23.76 mmHg × 0.99 = 23.56 mm Hg
Rounding to three significant figures: 23.6 mm Hg.
<h3>
Answer:</h3>
- The complete ionic equation is;
H⁺(aq)CHO₂⁻(aq) + K⁺(aq) OH⁻(aq) → K⁺(aq) CHO₂⁻(aq) + H₂O(l)
H⁺(aq) + OH⁻(aq) → H₂O(l)
<h3>
Explanation:</h3>
- The balanced equation for the reaction between HCHO₂ and KOH is given by;
HCHO₂(aq) + KOH(aq) → KCHO₂(aq) + H₂O(l)
- Ionic equation involves writing a balanced equation showing all the ions in a chemical reaction.
- The complete ionic equation will therefore be;
H⁺(aq)CHO₂⁻(aq) + K⁺(aq) OH⁻(aq) → K⁺(aq) CHO₂⁻(aq) + H₂O(l)
- Net ionic equation on the other hand, shows only the ions that are directly involved in the reaction and omits the spectator ions.
- The net ionic equation will be;
H⁺(aq) + OH⁻(aq) → H₂O(l)
Answer:
A
Explanation:
Got a calculation of 8.05297
Answer:
it gains energy in a quantized amount
Explanation:
when we describe the energy of a particle as a quantized ,we mean that only certain values of energy are allowed....it can only gain the exact amount of energy needed to reach one of the higher energy levels
hope this helps :)
Answer:
42 days
Explanation:
Half life = 8.4 days
Starting mass = 40.0 g
Time = ?
Final Mass = 1/16 * 40 = 2.5 g
First Half life;
Remaining mass = 40 / 2 = 20g
Second Half life;
Remaining mass = 20 / 2 = 10g
Third Half life;
Remaining mass = 10 / 2 = 5g
Fourth Half life;
Remaining mass = 5 / 2 = 2.5g
Time = Number of half lives * Duration of half life = 5 * 8.4 = 42 days
