The freezing point lowering of a saturated aqueous solution of NaCl is 17 Celsius. Would spreading salt on the icy sidewalks be beneficial when the temperature outside is -8 Fahrenheit? Explain.
What's your main problem with this? Is it not obvious that if NaCl will lower the f.p. by 17 C and the T is -8 then ....... What is the f.p. of pure H2O?
I'm not sure as to whether or not spreading salt on sidewalks would be beneficial, considering the outside temperature. The freezing point of pure H2O is 0 °C or 32 °F. But Im not sure what that would infer?
The freezing point is zero C normally. Spreading (or spraying) saturated NaCl solution CAN lower it by 17 degrees C according to the problem. The temperature is only -8 C, therefore, the ice would melt. In fact it would melt with an outside temperature of -16 C but it would not melt the ice if the outside temperature were -17 or lower. Anything higher than -17, yes.
To determine whether spreading salt on icy sidewalks would be beneficial when the temperature outside is -8 Fahrenheit, we need to understand the concept of freezing point depression.
Freezing point depression is a phenomenon where the freezing point of a solvent is lowered when a solute is added to it. In this case, the solute is sodium chloride (NaCl), commonly known as table salt.
The freezing point lowering can be calculated using the formula ΔT = Kf * m, where ΔT represents the change in freezing point, Kf is the cryoscopic constant (a property of the solvent), and m is the molality of the solute.
Given that the freezing point lowering of a saturated aqueous solution of NaCl is 17°C, we can convert -8 Fahrenheit to Celsius and see if it is below 17°C.
To convert -8 Fahrenheit to Celsius, we use the formula °C = (°F - 32) / 1.8.
-8 Fahrenheit converts to -22.2 Celsius.
Since -22.2°C is below 17°C, we can conclude that spreading salt on icy sidewalks would be beneficial when the temperature outside is -8 Fahrenheit. The salt would lower the freezing point of the water, preventing it from solidifying and melting the ice. This helps to reduce the formation of ice and makes the sidewalk safer to walk on.
Therefore, by understanding the concept of freezing point depression and performing the necessary calculations, we can determine whether salt would be beneficial in icy conditions.