So we look equation for the free Gibbs free energy (ΔG) which depends on entalpy (ΔH), temperature (T) and entropy (ΔS):
ΔG = ΔH - TΔS
ΔG is negative (-) because the water absorption on the silica gel surface is a spontaneous process.
ΔH is negative (-) because the water absorption on the silica gel surface is a exothermic process (it releases heat and if you want to desorb the water form the silica gen you need to add heat which is a endothermic process).
ΔS is negative (-) because the water is adsorbed, so from disorderly state you take the water molecules and put them in a orderly state and by doing that you decrease the entropy.
We can calculate how long the decay by using the half-life equation. It is expressed as:
A = Ao e^-kt
<span>where A is the amount left at t years, Ao is the initial concentration, and k is a constant.
</span><span>From the half-life data, we can calculate for k.
</span>
1/2(Ao) = Ao e^-k(30)
<span>k = 0.023
</span>
0.04Ao = Ao e^0.023(t)
<span>t = 140 sec</span>
Answer:
It depends what other values you have. Can you give more info? If they give density then you can solve for m.
Hydrochloric acid ionisation is as follows;
HCl ---> H⁺ + Cl⁻
HCl is a strong base so there's complete dissociation of acid to H⁺ ions
The number of HCl moles is equivalent to number of H⁺ ions present
1 L of solution contains - 11.6 moles of H⁺ ions
In 35 ml number of moles - 11.6 mol/L / 1000 ml x 35 ml = 0.406 mol
This number of moles are dissolved in 500 ml
therefore molarity = 0.406 mol /500 ml x 1000 ml = 0.812 M
Answer:
Silver tarnishes and becomes black when exposed to oxygen:
Diesel fuel burns when it is heated:
Explanation:
Chemical Changes are those changes in which the chemistry at molecular level is changed as the starting material is converted in to a new and different final material. This change takes place with the breaking of old bonds and forming of new bonds respectively.
Silver tarnishes and becomes black when exposed to oxygen:
This is a chemical change as Silver a white and lustrous starting material is being converted into a tarnish black final material. However, Silver doesn't readily react with oxygen at normal conditions. It readily react with Sulfur containing compounds in air and produces black compound as Ag₂S.
Diesel fuel burns when it is heated:
Diesel is a mixture of hydrocarbons ranging approximately from C₁₀H₂₀ to C₁₅H₂₈. When these hydrocarbons are burnt they produces a new materials i.e. CO₂ and H₂O.
C₁₀H₂₀ + 15 O₂ → 10 CO₂ + 10 H₂O
Hence, it is also a chemical reaction.
