Page 209 - Excel for Scientists and Engineers: Numerical Methods

186 EXCEL: NUMERICAL METHODS

where S is the mol/L of silver acetate that dissolve. Using the preceding
relationships, the following expression is obtained for the solubility S of
silver acetate:
+
K,
KO[ - 1) + S = 7
0.10
Find the solubility S.

5. Find the two sets of coordinates of the intersection of the straight line y = mx
+ b, where m = 5 and b = 50, with the parabola y = ax2 + bx + c, where a =
1.1, b = -2.3 and c = -30.5. Make a chart of the two series to show the
intersections.

6. Find the two sets of coordinates of the intersection of the straight line with y
= h and the circle of radius r (the equation of a circle is x2 + y2 = r; thus
).
y = 43 For example, use r = 1 and h = some value between 0 and 1.
The intersections will be at x, y = h and -x, y = h. Make a chart to show the
circle (values of x from -1 to 1 and calculated values of y, also same values
of x and -y).

7. Having solved problem #8, and having created the chart, use the values of the
intersections to create a chart series that shows the circumscribed rectangle
(four sets of coordinates: x, y = h; -x, y = h; x, y = -h; -x, y = -h). Use any
suitable method to find the coordinates of the circumscribed square.

8. For the chemical reaction
2A=B+2C
the equilibrium constant expression is

For this reaction, the value of the equilibrium constant K at a certain
temperature is 0.288 mol L-I.
A reaction mixture is prepared in which the initial concentrations are [A] = 1,
[B] = 0, [C] = 0 mol L-I. From mass balance and stoichiometry, the
concentrations at equilibrium are [A] = 1 - 2x, [B] = x, [C] = 2x mol L-',
4x3
from which the expression for K is . Find the value of x that
1 - 4~ - 4x2