Question

1. what is matter?anything that takes up space and has massa substance with fixed compositiontwo or more substances physically combineda mixture with variable composition14. h₂o is an example ofan atomic number.an element symbol.a chemical formula.15. _______ can be separated by physical means.an elementa compoundpure substancesmixtures

Explanation:

1. For question 13: The definition of matter is anything that occupies space and has mass. The other options describe pure substances, mixtures, which are subsets of matter, not the full definition.
2. For question 14: H₂O is a chemical formula that represents the compound water, showing the ratio of hydrogen to oxygen atoms. An atomic number is a number for an element, an element symbol is a single or two-letter code for an element, so these do not fit.
3. For question 15: Mixtures are physical combinations of substances, so their components can be separated using physical methods like filtration or distillation. Elements, compounds, and pure substances require chemical methods for separation.

Answer:

1. Anything that takes up space and has mass
2. a chemical formula.
3. Mixtures