I have a thermodynamics related question:?
A 500 g metal sphere is heated to 300 degrees Celsius, then dropped into a beaker containing 300 cm^3 of mercury at 20.0 degrees Celsius. A short time later the mercury temperature stabilizes at 99.0 degrees Celsius. Identify the metal: A) Iron B) Lead C) Aluminum
Can someone help me with this short Chemistry question?
124g of phosphorus vapor has the same volume as 71g of chlorine gas at the same temperature and pressure. What is the formula of a molecule of phosphorus? One mole of any gas at STP occupies a volume of 22.4 L One mole of two gases at the same temperature and pressure will occupy the same volume. The molar mass of Cl2 = 71 grams, so 71 g of Cl2 = 1 mole of Cl2. Since 124 g of phosphorus occupies the same volume as 1 mole of Cl2, 124 g of P = 1 mole of phosphorus vapor 1 mole of phosphorus atoms = 31 g 124 g/31g/mole = 4 moles of P atoms in 1 mole of phosphorus vapor. The formula of a molecule of phosphorus = P4
200 grams of water at 90°C is mixed with 100 gram of water at 30°C. What is the final temperature?
For temperatures between the freezing and boiling point of water, the heating curve is linear. Thus, we can use:((200 * 90) + (100* 30))/300Or: ((200 * 90)(temperature of first sample weighted by mass) + (100 * 30)(temperature of second sample weighted by mass) / (300)(total mass)to find the final temperature.100 can be factored out to get (2 * 90) + (1 * 30)) / 33 can be factored out every term: (2 * 30) + (1 * 10)(The factoring out just makes mental math easier; if a calculator is available doing so is unnecessary.)And then just work through the order of operations.60 + 10=70.So in mathematics, which assumes a perfect world, you get 70.
Four chemistry questions--no answers, just help?
I'm still stuck on this stupid lab that I started a day ago. The first part has a calculations area that is confusing me, and I was wondering if anyone can explain how to go about doing the problems..no answers are necessary, but teaching and helping is definitely welcome. It is listed in this order: title, procedure, data and observations (filled out), and calculations. Part I: The Dissolving of Solid Sodium Hydroxide in Water Procedure: 1. Measure out approximately 200 mL of distilled water and pour it into the calorimeter. Stir carefully with a thermometer until a constant temperature is reached. Record the volume of water and the constant initial temperature of the water on your data table. 2. Place a plastic measuring trough on top of the digital balance, and then zero the balance (press the tare button) so that the mass of the trough will be "ignored" and will not be added to the total mass measured by the balance. 3. Measure out approximately three to five scoops of solid sodium hydroxide and record the mass to your data table. 4. Place the solid sodium hydroxide into the water in the calorimeter and replace the lid immediately. Stir gently until the solid is completely dissolved and record the highest temperature reached. Data & Observations: Volume of H2O: 200.0mL H2O Mass of NaOH: 2.535g NaOH Initial temperature in calorimeter: 24.2C Final temperature in calorimeter: 27.8C Calculations: Show your work and write a short explanation with each calculation. 1. Write out a balanced "equation" for the process you investigated in Part I, including phase symbols. NaOH(s) + H2O(l) --> NaOH(aq) 2. Calculate the number of moles of sodium hydroxide dissolved. Show your work. 3. Calculate the amount of energy involved in this dissolving process. Show your work. 4. Determine the enthalpy change, per mole of sodium hydroxide dissolved. Show your work. 5. The value determined in question 4 is the enthalpy change value you will need for Conclusion question 1 below. With questions two to five, simply teaching is all that is necessary...it will help me learn instead of just giving the answers. Thank you so much in advance.
Physics question?
A 56.2 g silver spoon at 17.2°C is placed in a cup of coffee at 96.8°C. A short time later, the spoon is at 90.1°C. If, during this same time, the temperature of the coffee has fallen by 1.1°C, what is the mass of the coffee? (csilver = 0.056 cal/g°C and assume ccoffee = 1.0 cal/g°C)
Consider separate 1.0-L samples of He(g) Chemistry?
The root mean square velocity is given by: Vrms = √(3RT/M), where M is molecular weight of the gas. Given two gases of molecular weight M1 and M2 and at temperatures T1 and T2, if the root mean square velocities are the same, we can equate the two: √(3RT1/M1) = √(3RT2/M2) Solving for T1/T2: T1/T2 = M1/M2. The molecular weights of He and UF6 are 4 g/mole and 352 g/mole, respectively, so: TUF6 / THe = 352/4 = 88. The absolute temperature (ie., in Kelvins) of UF6 has to be 88 times higher than He for the root mean square velocities to be the same.
What is latent heat of evaporation?
Latent heat of vaporisation it is the energy (heat) required to transform a liquid mass at the boiling point (for example, water at 100°C at normal pressure) from liquid to gas.It is called "latent" (not seen, not registered) since this energy flow do not change the temperature so we can not "see" it.For water, is about 2264 kJ/kg or 2264 J/g or 541 cal/g.
What effect does temperature have on the relative humidity of an area?
High temperatures and high relative humidity (RH) means very high absolute humidity (grams of water vapour per cubic metre of air). There have been so many questions on this that I think Arden Buck equation - Wikipedia would help a lot. You can calculate saturation vapour pressure from the formula and then apply this rule: Vapour pressure in the air=saturation vapour pressure times RH. Therefore RH=vapour pressure/saturation vapour pressure. If you have a region in which air is heated under fairly constant pressure (which is the usual case over short periods), then the vapour pressure does not change, but the saturation vapour pressure does change. So RH changes and becomes less as temperature increases. Usually atmospheric pressure remains fairly constant over short time periods and we can say P=constant for short periods of time.