Ch5.3 Flashcards
(11 cards)
What does a chemical formula represent?
The elements in a compound and their relative proportions.
What does the formula H₂O tell us?
That water contains 2 hydrogen atoms and 1 oxygen atom.
When is a subscript not used in a chemical formula?
When there is only one atom of an element.
What is a polyatomic ion?
A group of atoms bonded together that acts as a single charged unit in a compound.
How are polyatomic ions written in chemical formulas?
In parentheses with a subscript outside if more than one ion is present (e.g., Ca₃(PO₄)₂).
What is a molecular formula?
It shows the kinds and exact number of atoms in one molecule of a compound.
Does a molecular formula show how atoms are arranged?
No, it only shows the number of each type of atom.
What is an empirical formula?
The lowest whole-number ratio of elements in a compound.
What are the molecular and empirical formulas for glucose?
Molecular: C₆H₁₂O₆, Empirical: CH₂O.
Can molecular and empirical formulas be the same?
Yes, if the formula can’t be simplified further (e.g., H₂O, NH₃).
