The concentration of calcium in a solution can be determined by measuring the intensiy of light emitted in a flame photometer.
Given the following data, write the equation for the line.
y = x +
Choose two points on the line, say (2, 0.4) and (12, 1.9)
The slope is (1.9-0.4)/(12-2) = 0.15
The y-intercept is y - mx = 0.4 - 0.15x2 = 0.1
Following on from question 1, if the reading of an unknown sample was 1.2, estimate its concentration
Calcium concentration of unknown sample = μM
Rearrange the equation to make x the subject
x = (y - 0.1)/0.15
substitute in y = 1.2
x = 1.1/0.15 = 7.3 μM
two significant figures are justified here.
Given the following data, find the equation for the line.
Choose two points on the line
say (10, 5.55) and (20, 4.7)
the slope is = (5.55-4.7)/(10-20)
the y intercept is 5.55 - (-0.085x10)
=5.55 + 0.85
the equation is y = -0.085x + 6.4
Following on from the previous question, if the value for y = 4.8, what is the corresponding value for x?
x = (two significant figures is appropriate here)
the equation is y = 6.4 - 0.085x
rearrange to make x the subject
x = (y-6.4)/-0.085
substitute in for y = 4.8
x = (4.8-6.4)/-0.085
x = 18.8 = 19 to 2 significant figures