A certain substance contains more than one kind of atom. Its atoms are chemically combined. Which term best describes the substance?

An experiment calls for a chemical with the formula $$NH_4$$  . How many atoms of each element are in the formula?

Which statement is supported from the data table?

A piece of an unknown metal has a mass of 35.6 grams and a volume of 5.0 $$cm^3$$ . What is the possible identity of the element?

Which best describes the particles that make up the part labeled X in the model?

Two pure substances consists of atoms that all have the same number of protons. However, the atoms of each substance have different numbers of valence electrons.

What must be true of these two substances?

Which grouping includes mostly elements that do not react readily?

A student mixes two substances together in a flask. Which observation could indicate that a chemical reaction is taking place in the flask?

Which chemical equation correctly demonstrates the law of conservation of mass?