Answer:
1. CaCO3(s) <=> CaO(s) +CO2 (g) Delta H = +178 kJ/mol
Since Delta H is positive, it means the reaction is endothermic
a. An increase in temperature will will shift the equilibrium position to the right, thus forming more products
b. A decrease in the temperature will shift the equilibrium position to the left, thus forming more reactants
2. PCl3(g) + Cl2(g) <-> PCl5 (g) Delta H= -88 kJ/mol
From the above, Delta H is negative which implies exothermic reaction.
c. Increasing the temperature will shift the equilibrium position to the left, thus forming more reactants.
d. Decreasing the temperature will shift the equilibrium position to the right, thus forming more products
A) James Cook.
B) He put his sailors on a strict diet to see if they would get scurvy.
C) Sauerkraut.
D) He told others of this diet and that none of his sailors died of scurvy.
E) Chemicals can be found almost anywhere and almost anyone can be a scientist.
Answer:
- 0.0413°C ≅ - 0.041°C (nearest thousands).
Explanation:
- Adding solute to water causes the depression of the freezing point.
<em>ΔTf = Kf.m,</em>
Where,
ΔTf is the change in the freezing point.
Kf is the freezing point depression constant (Kf = 1.86 °C/m).
m is the molality of the solution.
<em>Molality is the no. of moles of solute per kg of the solution.</em>
- <em>no. of moles of solute (glucose) = mass/molar mass</em> = (8.44 g)/(180.156 g/mol) = <em>0.04685 mol.</em>
<em>∴ molality (m) = no. of moles of solute/kg of solvent</em> = (0.04685 mol)/(2.11 kg) = <em>0.0222 m.</em>
∴ ΔTf = Kf.m = (1.86 °C/m)(0.0222 m) = 0.0413°C.
<em>∴ The freezing point of the solution = the freezing point of water - ΔTf </em>= 0.0°C - 0.0413°C = <em>- 0.0413°C ≅ - 0.041°C (nearest thousands).</em>
Answer:
The solution is not ideal.
The relative strengths of the solute-solvent interactions are greater compared to the solute-solute and solvent-solvent interactions
Explanation:
The total vapor pressure is the sum of the partial pressures of water and methanol, and they are calculated by the Raoult´s law equation:
Pₐ = Xₐ Pºₐ, where Pₐ is the partial pressure of component A
Xₐ is the molar fraction of A
P⁰ₐ is the pressure of pure A
So lets calculate the partial pressures of methanol and water and compare them with the given total vapor pressure of solution:
X H2O = 0.312 ⇒ X CH3OH = 1 - 0.312 = 0.688
PH2O = 0.312 x 55.3 torr = 17.3 torr
PCH3OH = 0.688 x 256 torr = 176.1 torr
Ptotal = PH2O + PCH3OH = 17.3 torr + 176.1 torr = 193.4 torr
This pressure is less than the experimental value of 211 torr. So the solution is not ideal. The relative strength of the solute-solvent interactions are greater than the solute-solute and solvent-solvent interactions.
The reason for this is the presence of hydrogen bonding between methanol and water.
