Question

a scientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas. which group of statements best describe all of the materials he is using in the investigation? ○ they are each compounds. each of the compounds is made of atoms. all of the atoms are made of matter. ○ they are each made of matter. some are compounds and some are elements. they all contain atoms. ○ they are all elements. some contain molecules of the same type of atom. some contain different types of atoms. ○ they are each made of matter. some are compounds made of one type of element. some are pure atoms.

Explanation:

1. Analyze each material: Water ($H_2O$) is a compound, silver (Ag) is an element, carbon dioxide ($CO_2$) is a compound, and oxygen gas ($O_2$) is an element.
2. Check each option:

• First option: Silver and oxygen gas are elements, not compounds, so this is wrong.
• Second option: All (water, silver, $CO_2$, $O_2$) are matter. Water and $CO_2$ are compounds; silver and $O_2$ are elements. All contain atoms (compounds have atoms of different elements, elements have atoms of the same type), so this is correct.
• Third option: Water and $CO_2$ are compounds, not elements, so this is wrong.
• Fourth option: Compounds are made of two or more different elements, and elements like silver are pure atoms, but the description of compounds as "made of one type of element" is incorrect, so this is wrong.

Answer:

They are each made of matter. Some are compounds and some are elements. They all contain atoms.