In the cchemistry lab we conducted an experiment called atomic spectroscopy.
We had to find the color, energy, wavelength, and 1/lamda for Hydrogen, neon, and mercury.
For hydrogen:
red 1.90ev 650nm 1.54e^-3
red 2.02ev 610nm 1.64e^-3
green 2.30ev 545nm 1.83e^-3
for neon:
green 2.30ev 550nm 1.82e^-3
red 2.05ev 610nm 1.64e^-3
red 1.80ev 690 1.45e^-3
yellow 2.12 580 1.72e^-3
blue 2.65 470 2.13e^-3
for mercury:
green 2.30ev 548 1.823^-3
red 2.05 590 1.69e^-3
violet 2.85 440 2.27e^-3
blue 2.55 470 2.13e^-3
yellow 2.15 570 1.75e^-3
for the first question we had to derive the equation that would allow us to find Planck's constant from your graph using the formulas
c= lamda X v and E=hv
The teacher said that the equation is h=slope / c
The next question says to show the calculations of Planck's constant, including the unit conversions, for mercury, neon, and hydrogen using the equation created above.
I am not sure how to do this. I do not know where to start.
We had to create graphs for neon and hydrogen on the computer so would i use the slope from there?
on the x axis was 1/wavelength (nm-1) and the y axis was energy(ev). The line for both graphs of neon and hydrogen was positive. So would I pick two points on the graph to find the slope and then do h=slope/c?
Chemistry - DrBob222, Tuesday, November 1, 2011 at 7:50pm
let w = wavelength (I can't type the symbol).
E = hc/w; So the slope is E/(1/w) = E*w.
You can see that E*w = slope = hc so slope/c = h.
Yes, pick a couple of points on the y axis and determine the slope.
Chemistry - Hannah, Wednesday, November 2, 2011 at 6:01pm
In the cchemistry lab we conducted an experiment called atomic spectroscopy.
We had to find the color, energy, wavelength, and 1/lamda for Hydrogen, neon, and mercury.
For hydrogen:
red 1.90ev 650nm 1.54e^-3
red 2.02ev 610nm 1.64e^-3
green 2.30ev 545nm 1.83e^-3
for neon:
green 2.30ev 550nm 1.82e^-3
red 2.05ev 610nm 1.64e^-3
red 1.80ev 690 1.45e^-3
yellow 2.12 580 1.72e^-3
blue 2.65 470 2.13e^-3
for mercury:
green 2.30ev 548 1.823^-3
red 2.05 590 1.69e^-3
violet 2.85 440 2.27e^-3
blue 2.55 470 2.13e^-3
yellow 2.15 570 1.75e^-3
for the first question we had to derive the equation that would allow us to find Planck's constant from your graph using the formulas
c= lamda X v and E=hv
The teacher said that the equation is h=slope / c
The next question says to show the calculations of Planck's constant, including the unit conversions, for mercury, neon, and hydrogen using the equation created above.
I forgot to mention that it says take the slope of either the manual or graph or two computer graphs and convert to appropriate units using the following:
1ev = 1.602 X 10^-9J
1 nm= 1 X 10^-9 m
On the computer graph for neon , there are two numbers at the top that say y=1246.7x and R^2=0.9996. Is the y value the slope?
It's tough to get the full question piece-meal over instead of all at one time. I must assume that y = 1246.7x means that is the equation for the straight line. If you remember your math, a straight line is y = mx + b so I presume 1246.7 is the slope. I don't know what R^2 is. Try 1246.7 for the slope and make a quick calculation; see if it is close to h. I can't help with R^2. My only guess, and it's just a guess, could that be the Rydberg constant squared? I don't know but it's worth a try.
ok thank you I apprieciate all of your help!!
To find Planck's constant using the equation h = slope / c, you need to first calculate the slope of your graph. Here's how you can do this:
1. Choose two points on the graph of the y-axis (energy) and x-axis (1/wavelength in nm^-1). Make sure these points are within the linear range of the graph.
2. Determine the change in y (energy) and change in x (1/wavelength) between these two points.
3. Calculate the slope of the line using the formula: slope = change in y / change in x.
4. Once you have the slope, you can calculate Planck's constant (h) by dividing the slope by the speed of light (c), which is approximately 3.00 x 10^8 m/s.
Now let's go through an example calculation for one of the elements you mentioned.
For neon, let's use the points (550 nm, 2.30 eV) and (470 nm, 2.65 eV) from the graph.
1. The change in y (energy) is 2.65 eV - 2.30 eV = 0.35 eV.
2. The change in x (1/wavelength) is 1 / 470 nm - 1 / 550 nm = 1.19 x 10^6 nm^-1.
3. Calculating the slope: slope = change in y / change in x = 0.35 eV / (1.19 x 10^6 nm^-1).
4. Convert the slope to appropriate units:
- 1 eV = 1.602 x 10^-19 J (given conversion factor).
- 1 nm = 1 x 10^-9 m (given conversion factor).
- So the slope in SI units is 0.35 x 1.602 x 10^-19 J / (1.19 x 10^6 x 1 x 10^-9 m).
Now, divide the slope by the speed of light (c) to calculate Planck's constant (h).
Remember, h = slope / c, where c is approximately 3.00 x 10^8 m/s.
Hope this helps!