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Describing Matter
Chapter 2 Section 1
Question | Answer |
---|---|
Matter | Anything that has mass and occupies space |
Chemistry | The study of the properties of matter and how matter changes. |
Substance | A single kind of matter that is pure and has a specific set of properties. |
Physical Property | A characteristic of a pure substance that can be observed without changing it into anothee substance. |
Chemical Property | A characteristic of a pure substance that describes its ability to change into a different substance. |
Element | A pure substance that cannot be broken down into other substances by chemical or physical means. |
Atom | The basic particles from which all substances are made. |
Chemical bond | The force that holds atoms together. |
Molecule | A neutral particle made of two or more atoms joined by covalent bonds. |
Compound | A pure substance made of two or more substances chemically combined. |
Chemical Formula | A combination of symbols that represents the elements in a compound and their proportions. |
Mixture | Two or more substances that are mixed together but not chemically combined. |
Heterogeneous Mixture | A mixture in which pure substances are unevenly distributer throughout the mixture. |
Homogeneous Mixture | A mixture in which substances are evenly distributed throughout the mixture. |
Solution | A well-mixed mixture containing a solvent and at least one solute that has the same properties throughout. |
What must you do in order to observe a chemical property of a substance? | try to change the substance to another substance. |
What is a molecule? | A particle made up of two or more atoms held together by chemical bonds. |
What information does a chemical formula tell you about a compound? | A chemical formula shows the elements in the compound and the ratio of atoms. |
what is the difference between physical properties and chemical properties? | Physical properties can be observed without changing pure substances into other substances. Chemical properties can be observed only by changing pure substances intoother substances. |
A metal melts at 450C. Is this property of the metal classified as chemical or physical? Explain your choice. | Melting point is a physical property because the metal is still the same substance, it is only changing form. |
Helium does not react with ant other substance. Is it accurate to say that helium has no chemical properties? Explain. | No. The fact that helium does not react with any other substance is a chemical property because it describes helium's ability to change (or not change) into different substances. |
How are elements and compounds similar? How do they differ? | Bothe elements and compounds are pure substances. While elements are not made of simpler substances, compounds are made up of two or more elements. |
How does a heterogeneous mixture differ from a homogeneous mixture? | You can see the different parts of a heterogeneous mixture, but substances in a homogeneous mixture are so thoroughly mixed that you cannot see them. |
Why is it correct to say that seawater is a mixture? | Seawater is a mixture made up of salt, water, and many other substances. |