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Why NaCl is very soluble but not CaO is only slightly soluble in water?
Its all to do with enthlapy and entropy. Anything which is soluble usually has a negative standard enthlapy of solution - the energy involved when 1 mole of solute dissolves in a solvent to give an infinately dilute solution. However, NaCl has a slightly positive enthalpy of solution, yet it dissolves. The reason for this is entropy - the change in the amount of disorder. When NaCl dissolves in solution, there is more chaos, more molecules within the solution. Any process that has a large positive entropy change will be favourable - spontaneous and can occur (reaction will 'go'). However, with CaO, the Ca2+ formed in solution has a high affinity (attraction to) for water molecules, hence a lot of water molecules are arranged orderly - less chaos and hence a negative entropy. This should in effect make the compound insoluble, however, the slight solubility is due to it still having a negative enthalpy change of solution - hence despite entropy it is still slightly soluble. (You may be asking how is dissolving CaO possible if entropy is negative? The entropy of the system maybe negative, but the entropy of the surroundings is positive (dissolving gives out heat - exothermic), hence the overall entropy (sum of both entropies) is positive and the reaction will 'go'.
Water and ethanol can be separated by heating the ethanol until it boils away from the water What type of change is this?
This is a physical change because the identity of the substances (water and ethanol) remains the same. The change is reversible, as both water and ethanol can be recovered from the separated mixture.
Is evaporation of ethanol a physical change?
Yes, evaporation, melting, and freezing are all physical changes. For it to be a chemical change, the substance would have to become a different substance. Evaporated ethanol is still ethanol, it is just in gas form.
Calculate the entropy of vaporization per mole of ethanol Given enthalpy change is 109.8 JK-1 mol-1 and boiling point of ethanol is 78.50C?
OK.With entalpy od vaporization and temperature of vaporization is very easy to calculate entropy of vaporization of etanol.So the equation to calculate this is:Delta_S=-Delta_H/TbWhere:Delta_S= Entropy of vaporizationDelta_H=Entalpy of vaporizationTb= Normal Boiling point temperatureSo the Delta_S become:Delta_S=-(-109000.8)/(78.5+273)Delta_S=310.1 J.mol-1.K-1
Is there any temperature change on mixing ethanol and water?
No, there is no temperature change when mixing ethanol and water because they form a homogenous solution. The heat released during solvent mixing is offset by the heat absorbed during solvent separation.
What describe the entropy change as a solution is made from a liquid and solid?
In this case the entropy increase.
What describes the entropy change as a solution is made from a liquid and a solid?
In this case the entropy increase.
What describes the entropy change as a solution is made from a liquid and solid?
In this case the entropy increase.
Does the pH of ethanol change if water is added?
Yes, adding water to ethanol will change its pH. Ethanol is a neutral compound with a pH of around 7. However, adding water will dilute the ethanol, potentially changing its pH depending on the amount of water added and the initial concentration of the ethanol solution.
Why is ethanol change in color after putting ferrox paper?
The change in color of ethanol when exposed to ferrox paper is due to the reaction between ethanol and the iron salts present in the ferrox paper. This reaction causes the ethanol to oxidize, leading to a color change in the solution.
How does the entropy change in the reaction 2c3h6g 9o2g 6co2g 6h2og?
The entropy change in a reaction can be calculated by comparing the entropy of the products to the entropy of the reactants. Without specific entropy values provided, it is difficult to determine the exact change. However, in general, the entropy change is positive in reactions where the products have higher entropy than the reactants, indicating an increase in disorder.
Entropy change for dissolving salt in water?
This question isn't very complete, but if you meant what is the solute or solvent, the water would be the solvent because there is more water than salt. In this case, the salt is the solute. If there...
Will this entropy change by positive or negative?
If the system becomes more disordered, the entropy change will be positive. If the system becomes more ordered, the entropy change will be negative.
When is the change in entropy zero?
The change in entropy is zero when a process is reversible, meaning that the system and surroundings return to their original state without any net change in entropy.
When does the change in entropy equal zero?
The change in entropy equals zero when a process is reversible, meaning that the system and surroundings return to their original state without any net change in entropy.
What will happen to the boiling leaf when in ethanol what will happen to the leaf and the ethanol?
When you boil a leaf in ethanol, the ethanol will extract the pigments and other compounds from the leaf. The chlorophyll will dissolve in the ethanol, causing the leaf to lose its green color and appear pale. The ethanol will take on the color of the extracted pigments, turning it into a green solution.
What describes the entropy change as a solution is made from a liquid to a solid?
S > 0
