Question

1. A metal sample, at 20. degree Celsius, has a heat capacity of 0.25 J/C. How much heat it must absorb to increase its temperature to 53 degree Celsius?

2. In a coffee-cup calorimeter, 50.0 g hot water at 60.0 C was mixed with 50.0 g cold water at 20.0 C. If the final temperature is 36.9, what is the heat capacity of the calorimeter in J/C? Specific heat of water is 4.184 J/(g C)

3. Green line of Hg lamp has a wavelength of 546.1 nm. What is the energy of photon associated with this green line?

4. The lines observed in H-lamp are parts of Balmer Series. All these lines are due to a transition from various higher n value to a common n. What is this common lower n value for all these lines? (1, 2, 3, or 0?)

Answer 1

1) q = C * dT
q = 0.25 * (53-20)
q = 8.25 J

2) Heat lost by Hot water = Heat gain by cold water
q for hot water = 50 * 4.184 * (36.9-60)
q = - 4832.5 J
q for cold water = 50 * 4.184 * (36.9 - 20)
q = 3535.48 J
heat capcity of Caloriemeter = 4832.5 - 3535.8
haet capcity = 1296.7J

3) wave length = 546.1 nm
E = hc / lamda
E = (6.625 * 10^-34 * 2.998 * 10^8) /(546.1 * 10^-9)
E = 3.637 * 10^-19 J

4) for all Balmer series spectral lines the lowest n valu is 2. And all these lines are fall in the region of visible light.