What is pure substances

Drop some thnx plz...

In chemistry, a pure substance is a sample of matter with both definite and constant composition and distinct chemical properties.

Explanation:

Pure substances are substances that are made up of only one kind of particles and has a fixed or constant structure. Everything that exists in the earth is a form of a matter which is further defined as any substance that occupies space and has mass. The matter is further divided into various forms such as solid, liquid and gas. Apart from these, it is also classified as pure substances and mixtures.

23.5

23.5

47.0

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.