Solving Calorimetry Ques: Molybdenum Specific Heat

  • Thread starter Thread starter vg19
  • Start date Start date
  • Tags Tags
    Calorimetry
AI Thread Summary
To find the specific heat of molybdenum, use the principle that the heat lost by the molybdenum equals the heat gained by the water. The molybdenum stick, weighing 237g, cools from 373K to 288K, while the water, weighing 244g, heats from 283K to 288K. The heat gained by the water is calculated as 5113.6J using its mass and specific heat. Setting the heat lost by molybdenum equal to the heat gained by water allows for solving the specific heat, resulting in 0.243 J/gK for molybdenum. This method effectively demonstrates the conservation of energy in the system.
vg19
Messages
67
Reaction score
0
Hi,

I have 1 question that I am having trouble with.

1) A stick of molybdenum weighing 237g and starting at a temperature of 373Kelvin is thrust into 244g of water starting at 283Kelvin. If the final Temperature observed for the whole system is 288Kelvin, what would the specific heat of the molybdenum be? Ignore the calorimeter.

For this question I think I am suppose to use the heat lost/gained = mass x C x Temp Change formula and solve for C. However, I am confused on what values to sub in. There are 2 masses, and different temperature.

Any help is much appreciated

Thanks
 
Physics news on Phys.org
Think like this, the heat lost by molydenum = heat gained by water. m_{Mo}C_{Mo}(373-288)=m_{water}C_{water}(288-283). Water's follows water's, Mo's follows Mo's.
 
for the question! Let's break this problem down step by step. First, we need to determine the heat lost by the molybdenum stick and the heat gained by the water. We can do this by using the formula Q = mCΔT, where Q is the heat, m is the mass, C is the specific heat, and ΔT is the change in temperature.

For the molybdenum stick, we have a mass of 237g and a temperature change of 373K-288K = 85K. Plugging these values into the formula, we get Q = (237g)(C)(85K).

For the water, we have a mass of 244g and a temperature change of 288K-283K = 5K. Plugging these values into the formula, we get Q = (244g)(4.18J/gK)(5K) = 5113.6J.

Now, since energy is conserved in a closed system, we can set these two equations equal to each other and solve for C. This gives us:

(237g)(C)(85K) = 5113.6J

Solving for C, we get C = 0.243 J/gK. Therefore, the specific heat of molybdenum is 0.243 J/gK.

I hope this helps! Let me know if you have any other questions.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top