Are these physical or chemical Hydrogen is a colorless, tasteless and odorless gas. Hydrogen is very combustible in the presence of oxygen. Hydrogen is very reactive with most elements. Hydrogen is the least dense of all elements.

1. Hydrogen being colorless, tasteless, and odorless are all physical properties.

2. Hydrogen being combustible is a chemical property.

3. Hydrogen being reactive is a chemical product.

4. Hydrogen being less dense is a physical property.

- Therefore your answers are physical, chemical, chemical, and physical.

Explanation:

First, recognize the difference between physical and chemical properties. (look up the defintions and apply what you have learned to these problems)

Afterward, you should note physical properties include odor, taste, appearance, melting point, boiling point etc... where as chemical properties include the chemical reaction, changes at molecular level, combustion, and reactivity.

Finally, use this knowledge to answer these questions and any others.