An atom or group of atoms with a charge (+ or - ) because it either gained or lost an electron, is known as this.

Distilled water has a neutral pH. What number is it on the pH scale?

Solutions with a pH lower than 7 are considered:

Seawater has an average pH of about 8.1 so this makes it:

These are different varieties of an element that have varying numbers of neutrons, and therefore have different mass. Examples are carbon 12, carbon 13, and carbon 14.

Solid water melting and becoming liquid water, and evaporating to water vapor:

Even when Nitrogen goes through different phases in the nitrogen cycle, it is neither created nor destroyed, but recycled. This is known as the Law of Conservation of:

How many elements are known and identified?

Photosynthesis and cellular respiration are examples of this. Choose all that apply:

Which is the correct order of smallest to largest?