Matter is anything with (1) and volume. A (2)
is a form of
matter with a uniform and unchanging composition. Substances have specific, unchanging
(3)
that can be observed. Substances have both physical and chemical properties.
properties colate observed without changing a substance's chemical
composition. Color, hardness, and (5)
are examples. Other properties cannot be
observed without changing the composition of a substance. These are called (6)
properties
An example is the tendency of iron to form rust when exposed to air.

Matter is found all around us and is present in all substances in the universe. Substances have a uniform composition and changes in this composition of of a substance is called chemical reaction.

The appropriate words that fill in the blanks are;

1) Mass

2) Substance

3) Properties

4) Physical

5) Density

6) Chemical

Matter has mass and occupy space. Matter with a uniform and unchanging composition is called a substance.

Substances have physical and chemical properties. The physical properties of a substance such as density can be observed without changing the composition of the substance.

Chemical properties of a substance such as rusting can only be observed when the chemical composition of the substance is altered(chemical reaction).

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c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.