8th Grade- Mixture, Compounds, and Pure Substances

Front

What is a pure substance?

Back

A pure substance is a material that has a constant composition and consistent properties throughout. It can be an element or a compound.

Front

What is a mixture?

Back

A mixture is a combination of two or more substances where each substance retains its own properties. Mixtures can be homogeneous or heterogeneous.

Front

What is the difference between a compound and a mixture?

Back

A compound is a substance formed when two or more elements chemically bond together, resulting in new properties. A mixture is a physical combination of substances that do not change their individual properties.

Front

What is the chemical formula for table salt?

Back

The chemical formula for table salt is NaCl, which indicates it is composed of sodium (Na) and chlorine (Cl) atoms.

Front

What is a chemical change?

Back

A chemical change is a process that involves the transformation of one or more substances into different substances with new chemical and physical properties.

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What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition.

Front

What is the pH scale?

Back

The pH scale is a measure of how acidic or basic a solution is, ranging from 0 to 14, with 7 being neutral.

Front

What is the only substance with a neutral pH of 7?

Back

Pure water has a neutral pH of 7.

Front

What happens to the properties of elements when they form a compound?

Back

When elements combine to form a compound, they create a substance with completely different properties from the individual elements.

Front

What is an example of a physical change?

Back

Melting ice is an example of a physical change, as it changes from solid to liquid but remains water (H2O) in both states.