During a titration a student found that 20.0cm3 of sodium carbonate solution neutralised 27.9 cm3 of 0.500 mol/dm3 nitric acid solution.
Calculate the concentration of the sodium carbonate solution in mol/dm3. Give
your answer to 3 significant figures.

How are elements arranged in a periodic table

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.

Which of the following best describes the formation of plasma?