Interviewer: How does salt save lives and help driving conditions?
Shania: Well, I am glad you asked. Lets start at the beginning, salt is mostly used on roads before it storms to prevent ice, also during and even after! (Yes it is used on side walks and such, but we are just going to talk about roads for right now.)
Interviewer: How does salt work before a storm?
Shania: When salt is laid down before a storm and then snow begins, the salt is dissolved into the first snowflakes and continues to do so. The reason why the salt water doesn't freeze is because it has a lower freezing point than snow.
Interviewer: Okay, I get it, but how does it work on already formed ice?
Shania: Plow trucks and salt trucks are constantly out on the roads working to keep driving conditions safe and they keep adding for salt on the snow and ice. On the outer part of the salt the water molecules are more active and so when the salt comes into contact with this water it is dissolved into it. That is how the process begins and when cars drive over this slush it compacts the ice and salt together making it more effective.
Interviewer: How is Chemistry at work?
Shania: Well, Chemistry is at work when it comes to salt. As we all know the chemical formula of salt is NaCl and this dissociates into two ions: Na+ and Cl-. Then,
"Magnesium chloride and calcium chloride dissociate to three ions each because the metal has a 2+charge and there are two chlorides per metal ion:
MgCl2(s)-->Mg2+(aq) + 2Cl-(aq)
CaCl2(s)-->!Ca2+(aq) + 2Cl-(aq)."
All of this put together increases the effectiveness of salt.
Interviewer: How do you feel about this information?
Shania: The information that I read in the article I used in this conversation surprised me a lot. I knew that salt melted snow, but I didn't know all of the intricate details or the reasoning behind how it works. It was a very interesting reading experience and I know I will remember this information for along time to come.
I summarized and quoted from the article below: