Answer:
All of the above processes have a ΔS < 0.
Explanation:
ΔS represents change in entropy of a system. Entropy refers to the degree of disorderliness of a system.
The question requests us to identify the process that has a negative change of entropy.
carbon dioxide(g) → carbon dioxide(s)
There is a change in state from gas to solid. Solid particles are more ordered than gas particles so this is a negative change in entropy.
water freezes
There is a change in state from liquid to solid. Solid particles are more ordered than liquid particles so this is a negative change in entropy.
propanol (g, at 555 K) → propanol (g, at 400 K)
Temperature is directly proportional to entropy, this means higher temperature leads t higher entropy.
This reaction highlights a drop in temperature which means a negative change in entropy.
methyl alcohol condenses
Condensation is the change in state from gas to liquid. Liquid particles are more ordered than gas particles so this is a negative change in entropy.
Answer:
1. 389 kJ; 2. 7.5 µg; 3. 6.25 days
Explanation:
1. Energy required
The water is converted directly from a solid to a gas (sublimation).
They don't give us the enthalpy of sublimation, but
The equation for the process is then
Mᵣ: 18.02
46.69 kJ + H₂O(s) ⟶ H₂O(g)
m/g: 150
(a) Moles of water
(b) Heat removed
46.69 kJ will remove 1 mol of ice.
2. Mass of water vapour in the freezer
For this calculation, we can use the Ideal Gas Law — pV = nRT
(a) Moles of water
Data:
V = 5 L
T = (-80 + 273.15) K = 193.15 K
Calculation:
(b) Mass of water
3. Time for removal
You must remove 150 mL of water.
It takes 1 h to remove 1 mL of water.
Answer:
Passivation of Oxide layers of the metals.
Explanation:
Passivation is a non-electrolytic finishing process that makes most metals rust-resistant. The prosses removes free iron from the surface by using either nitric or citric acid. When this happens, it results to an inert, protective oxide layer that is very slow or less likely to chemically react with air and cause corrosion.
Passivity caused many of the metals several minutes to begin to react. Once the finishing process that makes metals less likely to react was eroded, reaction was initiated vigorously.
I think that the answer might be D beacuse if he body lacks calcuim thier DIET is low on calcium
<span>magnesium and sulfur
(Magnesium
is in family two which tends to form ionic bonds)(Elements in families 1
and 2 are very active metals that tend to form ionic bonds)</span>
