Please go to the link below and answer the questions that follow. Please include
ID: 856926 • Letter: P
Question
Please go to the link below and answer the questions that follow. Please include as much detail as you can bc i'm awarding a lot of points.
tinyurl.com/79a74w5
1. Describe the changes you observe in the animation, including changes in the bonds and/or particulate attractions and changes in the amount of disorder (randomness) in the system.
2. When sodium chloride is dissolved in water, the temperature of the resulting solution is lower than the temperature of the water before the salt dissolves. Is this dissolution process endothermic or exothermic? Justify your response.
3. When some ionic salts are dissolved in water, the temperature of the resulting solution is higher than the temperature of the water before the salt dissolves. What determines whether the resulting solution is cooler or warmer than the starting water?
4. why do some salts, such as sodium chloride, dissolve spontaneously (in a thermodynamically favored process) even though the process is endothermic overall.
Explanation / Answer
1)This shows the dissolution of an ionic compound into water.Here NaCl.
For ionic compounds, dissolution takes place when the ionic lattice breaks up and the separate ions are then solvated. This most commonly occurs in polar solvents, such as water.
NaCl(s) ? Na+(aq) + Cl-(aq)
After the lattice breaks the ions are unstable.If they are not solvated then they may attract each other and form the molecule can.Hence positive part of water molecule suurounds the negative ion and solvate it.
And negative part of water molecule solvates the positive part.THus there is the dissolution.
Overall randomness increases.
2)Exothermic reactions give off heat (product). It gives off heat to its surrounding (the water). The extra heat makes the solution hotter.Hence the temperature rises.
On the other hand, endorthermic reactions require heat to proceed. The heat that they use up comes from the solution. Since heat is being used up, the temperature drops.In the above said temperatue drops
Hence the above is endothermic reaction.
3)The type of reaction determines whether the resulting solution is cooler or warmer than the starting water.
If cooler because reaction is endothermic and warmer because reaction is exothermic.
4)Most reactions that are spontaneous are exothermic as every system wants to lessen its energy
But here are some factors that dominate the energy aspect
i)Here there is an increase in entropy.Randomness increases .
ii)The polarity of water molecules enables water to dissolve many ionically bonded substances
.
iii)Salt (sodium chloride) is made from positive sodium ions bonded to negative chloride ions.
iv)Water can dissolve salt because the positive part of water molecules attracts the negative chloride ions and the negative part of water molecules attracts the positive sodium ions.