I have electric heat wires on the roof and in the gutters.. i rake after every snow fall... I have the only house on the street with out ice dams....
the reason for CaCl is because it relies on a chemicle reaction to work ( just add water) rock salt requires help from the sun and warmer temps...
My lawn is crab grass.... i couldnt kill it if I wanted to...
Rock salt is Sodium Chloride - NaCl. Calcium Chloride is CaCl2. When NaCl dissolves, there are two ions - one of Na and one of Cl. When CaCl2 dissolves, there are three ions, one of Ca and two of Cl. That's why Calcium Chloride works better. Both are chemical reactions - they lower the temperature at which water freezes - so they cause ice to melt as long it the temperature is above the new freezing temp.
Rock salt is Sodium Chloride - NaCl. Calcium Chloride is CaCl2. When NaCl dissolves, there are two ions - one of Na and one of Cl. When CaCl2 dissolves, there are three ions, one of Ca and two of Cl. That's why Calcium Chloride works better. Both are chemical reactions - they lower the temperature at which water freezes - so they cause ice to melt as long it the temperature is above the new freezing temp.
I hate to nitpick, but isn't dissolving a physical change? You mix table salt into water, then evaporate all the water and you'll still have table salt. If it were a chemical reaction, then a new compound would have to be created.
Dissolving salts into water raises the boiling point of water and lowers the freezing point. I believe calcium chloride lowers the freezing point more than NaCl would and is why it is more effective at dealing with ice.
I always loved chemistry in college is high school.
I hate to nitpick, but isn't dissolving a physical change? You mix table salt into water, then evaporate all the water and you'll still have table salt. If it were a chemical reaction, then a new compound would have to be created.
Dissolving salts into water raises the boiling point of water and lowers the freezing point. I believe calcium chloride lowers the freezing point more than NaCl would and is why it is more effective at dealing with ice.
I always loved chemistry in college is high school.
No quite correct, JD.
Is mixing calcium chloride and water a chemical reaction?
Answer YES
CaCl2(aq) + H2O(aq) = 2HCl(aq) + CaO(s)
You con't get CaCl2 back.
More importantly for melting snow: the reaction is exothermic giving off HEAT.
(thermometer is in Celsius)
Last edited by PRBuzz; 02-07-2011 at 02:41 PM..
Given the diversity of the human species, there is no “normal” human genome sequence. We are all mutants.
Is it called the eutectic point ?
Haven't thought of it since Charlie Waughs 1972 chemistry class, all I wanted to do was burn stuff . . . . . boy did I ever.
When we use either CaCl2 or NaCL to melt ice , its because it lowers the melting point of the water. There is virtually no contribution of an exothermic reaction at the very low levels it gets diluted to when you use a sprinkle of salt on an icy surface. yes , a spoon full in a small amount of water will raise the temp but for the use in melting ice , its all Phase diagram stuff , not exeothermic reaction. It actually will lower freezing point to -50 degrees at a 30 wt% solution but my guess is that at the concentrations we use , it might lower it 4 degrees or so.
The experiment to prove this using the video shown , would to be to put the reacted mixture that was raised to 50C inot a freezer. The freezing point of the water would be way low , maybe approaching -50 C at the concentration he used. Remember , in the freezer you are not taking the salt out. You are just taking heat out and even though all the heat of the reaction is gone , the water with the same salt in it still has that hugely lowered melting point.
To read more , search for "water/Calcium Chloride Phase Diagram.
When we use either CaCl2 or NaCL to melt ice , its because it lowers the melting point of the water. There is virtually no contribution of an exothermic reaction at the very low levels it gets diluted to when you use a sprinkle of salt on an icy surface. yes , a spoon full in a small amount of water will raise the temp but for the use in melting ice , its all Phase diagram stuff , not exeothermic reaction. It actually will lower freezing point to -50 degrees at a 30 wt% solution but my guess is that at the concentrations we use , it might lower it 4 degrees or so.
The experiment to prove this using the video shown , would to be to put the reacted mixture that was raised to 50C inot a freezer. The freezing point of the water would be way low , maybe approaching -50 C at the concentration he used. Remember , in the freezer you are not taking the salt out. You are just taking heat out and even though all the heat of the reaction is gone , the water with the same salt in it still has that hugely lowered melting point.
To read more , search for "water/Calcium Chloride Phase Diagram.
I like that...on a grand scale. I'm a single molecule scale guy!
If there is no water and its below freezing...each crystal/molecule CaCl2 on a molecular scale reacts with snow/ice to generate water based upon mini-exothermic reactions, e.g. ice melts. The thing cascades and makes more water which dissolves more CaCl2. The more water the more CaCl2 dissolved the lower the freezing point which causes more ice to melt.
Given the diversity of the human species, there is no “normal” human genome sequence. We are all mutants.
Given the diversity of the human species, there is no “normal” human genome sequence. We are all mutants.
Hybrid Mode
