If you have 500 mL of a 0.10 M solution of the acid, what mass of the corresponding sodium salt of the conjugate base do you need to make the buffer with a pH of 7.65 (assuming no change in volume)? Express the mass to two significant figures and include the appropriate units.

Nitrogen (n), phosphorus (p), and potassium (k) are the main nutrients in plant fertilizers. according to an industry convention, the numbers on the label refer to the mass percents of n, p2o5, and k2o, in that order. calculate the n: p: k ratio of a 30: 10: 10 fertilizer in terms of moles of each element, and express it as x: y: 1.0.

If the density of water is 1.0 g/cm3, which of these materials would float in water, based on their densities? check all that apply. aluminum cork iron lead wax

What is the most common reason for matter changing its state?