You need to prepare a stock solution at ph 7.00 with kh2po4 and na2hpo4 (pka =7.21). what would be the respective concentration of these substances if you wish to obtain the final phosphate concentration [hpo4 −2 ] + [h2po4 − ] = 0.3 m? b. what will be the ph of the solution after adding 0.18 l of 0.2 m naoh?

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

Pastoral farming is best described as a. a method of raising livestock and moving herds b. an african method of agriculture c. a method of cultivating crops on poor soils d. a common method of desert farming select the best answer from the choices provided a b c d

Hey, could someone me answer this? much appreciated!