Question

1. *the particle diagrams above represent a ___ change because ___.

a. chemical; the sample changes in identity from the start to the end.
b. chemical; the sample retains its identity from the start to the end.
c. physical; the sample changes in identity from the start to the end.
d. physical; the sample retains its identity from the start to the end.

1. matter that is composed of two or more different elements chemically combined in a fixed proportion is classified as _____

a. a compound
b. a mixture
c. an element

Explanation:

• For question 4: In a physical change, the substance retains its identity. In a chemical change, the identity changes.
• For question 5: A compound is formed when two or more different elements are chemically combined in a fixed proportion. A mixture has substances not chemically combined. An element is a single type of atom.

Answer:

1. d. Physical; the sample retains its identity from the start to the end.
2. a. a compound