Calibration curve. (You can do this exercise with your calculator, but it is more easily done by the spreadsheet in Figure 4-15.) In the Bradford protein determination, the color of a dye changes from brown to blue when it binds to protein. Absorbance of light is measured. Protein (g): 0.00 9.36 18.72 28.08 37.44 Absorbance at 595 nm: 0.466 0.676 0.883 1.086 1.280 4 (a) Find the equation of the least-squares straight line through these points in the form y [m(sm)]x [b(sb)] with a reasonable number of significant figures. (b) Make a graph showing the experimental data and the calculated straight line. (c) An unknown protein sample gave an absorbance of 0.973. Calculate the number of micrograms of protein in the unknown and estimate its uncertainty.

2.7 Density Density is basically the relative heaviness of an object The formula is D = m/v A deviation that might have to be used is M = D x V Density is a physical property of matter. The density of water @ 4 ° Celsius is 1.00 g/ml Use density to calculate mass from volume Example 1: Mercury has a density of 13.6 g/ml. What size bottle will contain 13.6 g/ml 13.6 x 1ml = 8.35 ml 13.6 g 3 Example 2: Gold has a density of 19.3 g/ cm . What’s the mass of a gold cube with 1.27 cm sides (a ½ inch cube). ** This problem will use the deviation I listed in the bullets above** cm V = (1.27 ¿¿3 = 2.05 3 cm