Im kinda lost in my inorganic chemistry class, and all these different equations and formulas are confusing me. I was given some problems and was wondering if someone could please explain them to me. I will post them separatly.(they dont offer tutors in the summer ) At 1 atm, how much energy is required to heat 88.0g of H20(s) at - 16.0 degrees celcius to H2O(g) at 127 degrees celcius?
For this problem the answer is easy because 1 gram of water needs a calor to go up a degree in temperature. so 88 grams is 88 calories per degree celcius
Oh yeah when the substance you are talking about is not water you need to look up the specific heat and find the energy (in calories or joules) that way. Specific heat is usually in a table in your book. Make sure you give the correct units of energy. Also this is not inorganic chemistry, it is general chemistry.
Is that the exact wording of the problem? I didn't notice it says 127 degress, that means you also have to find the energy of changing it from a liquid to a gas (steam) it is just a constant (specific to water) that you multiply by the mass.
Analyzing the question here, there are 5 different stages of heating: 1. energy needed to heat the H2O solid from -16 Celsius to 0 Celsius 2. energy needed to melt the H2O solid to H2O liquid 3. energy needed to heat the H2O liquid from 0 to 100 Celsius 4. energy needed to boil H2O liquid to H2O gas 5. energy needed to heat the H2O gas from 100 celsius to 127 celsius http://springprojectwhs.tripod.com/id9.html Formula for heat energy: H = Cp*m*(delta T) H = Heat energy (in Joules) m = mass (in kilograms) delta T = change in temperature (in degrees Celsius) Cp = Specific heat (in J/kg x degrees C) plugging in the values for Cp, m (convert your g to kg), and delta T would give you the heat energy for steps 1, 3, and 5 Another website: http://www.bbc.co.uk/schools/gcsebi...eway/energy_home/0_heating_houses_print.shtml Gives you the formula and the specific heat valeus for melting and boiling water to calculate heat energy for steps 2 and 4. Add all the steps together to get the comprehensive heat energy needed. Hope that helps
Don't forget about heat of fusion and heat of vaporization. In addition to energy required to raised the temperature, energy is also required to change state (solid to liquid, liquid to gas and vice versa.) These problems are not hard as long as you're careful in breaking down the steps. In this particular problem, water goes through 3 phases and 2 phase changes. So you can divide it into 5 parts: energy required for temperature change for 3 phases and energy required for 2 phase changes. 1) -16 to 0 degree. Solid phase. energy = specfic heat of ice * deltaT * mass 2) 0 degree. Solid to liquid phase change. energy = heat of fusion * mass 3) 0 to 100 degree. Liquid phase. energy = specfic heat of water * deltaT * mass 4) 100 degree. Liquid to gas phase change. energy = heat of vaporization * mass 5) 100 to 127 degree. Gas phase. energy = specfic heat of water vapor * deltaT * mass Remember the same applies when you work in the other direction (remove energy to make gas into solid). It will have different names such as heat of condensation instead of vaporization, but the value is exactly the same. For material that goes straight from solid to gas, there's heat of sublimation, but the process is exactly the same. -Jeff
In my day, we used to learn from studying books, and walking to school in 10 feet of snow... Just kidding, anyways I wish I had this sort of thing back when I was still taking classes. If only I was born 10 years later...
These kids has it so easy nowaday. Just Google and all your answers are there. I remembered spending hours and hours on research in the libraries and looking at books.
