Why should it be any more costly to clean up the last 10 percent of polluted air than to clean up the first 90 percent?

Asap! how do you lengthen a pattern piece? (family and consumer science, sewing)

Which atom or ion is the largest? a. k b. k+ c. ca d. ca2+ e. li

For the reaction, 4 a(g) + 3 b(g) => 2 c(g), the following data were obtained at constant temperature. experiment initial[a],mol/l initial [b],mol/l initial rate,m/min 1 0.200 0.150 5.00 2 0.400 0.150 10.0 3 0.200 0.300 10.0 4 0.400 0.300 20.0 which of the following is the correct rate law for the reaction? 1. rate = k[a]2[b]2 2. rate = k[a][b] 3. rate = k[a]2[b] 4. rate = k[a][b]2