The sum of the total number of bonds between chromium and oxygen atoms in chromate and dichromate ions is ____________.

10.30 mg of O₂ is dissolved into a liter of sea water of density 1.03 g/mL. The concentration of O₂ in ppm is__________.

Consider the following reactions


The mass percentage of carbon in A is ______.

The following system of linear equations
7x + 6y – 2z = 0
3x + 4y + 2z = 0
x – 2y – 6z = 0, has