im supposed to find the
slope= -EA/R = triangle y/triangle x = (y2-y1) ________/(x2-x1)____________
how do i do this? is it the same as the slope that excel gave me?
i have information from 3 different groups, and i have 3 x's and 3 y's, how do i solve this? the teacher told us that since K from our last experiment is wrong we should use rate, but i have 3 rates.
Also, how do i find the Ea from this graph?
img207.imageshack.us/img207/6375/2ndgraph.jpg
do i subtract 11-9=2?
I don't know what you plotted on Excel but slope is slope.
he gave us an example of what the slope might be in class and it was -1.3x10^2 but my slop is completely different, was i supposed to do calculations? or just get the one from excel?
what do i put in the 2 blanks?
To find the slope using the formula you provided, you need to have two points on your graph. Let's call these points (x1, y1) and (x2, y2).
To calculate the slope:
1. Determine the values of y2, y1, x2, and x1 from the data you have for each group. Make sure you select two points that are relevant for finding the slope.
2. Plug the values into the slope formula you provided:
slope = (y2 - y1) / (x2 - x1)
Substitute the values into the formula, and calculate the slope for each group separately.
The slope you calculated using this formula is different from the slope that Excel gave you. Excel usually calculates the slope using a different method called linear regression, which considers all the data points to derive the best-fit line.
Now, regarding finding the Ea (activation energy) from the graph you shared, the graph itself does not directly provide the activation energy. Instead, the Ea can be determined by performing an Arrhenius plot using multiple data points.
1. Gather data points from your experiment at different temperatures. You should have data pairs of ln(rate) versus 1/T (K), where rate is the value you calculated earlier.
2. Plot ln(rate) on the y-axis and 1/T (K) on the x-axis.
3. Fit a straight line to the points on the graph using linear regression or a curve-fitting tool in Excel. The slope of this line will be equal to -Ea/R, where R is the ideal gas constant.
4. To find the activation energy (Ea), you can rearrange the equation to solve for Ea:
Ea = -slope * R
Substitute the value of the slope you calculated in Step 3, and solve for Ea by multiplying it by the gas constant (R ≈ 8.314 J/(mol·K)).
Regarding your question about subtracting 11-9 to find Ea, the value you calculated is not related to the activation energy. The activation energy is determined by analyzing the relationship between ln(rate) and 1/T, as explained above.
Remember, it's always important to carefully interpret the data and use appropriate analysis methods to derive accurate results.