module 12.2- compounds

Question 1

what is an empirical formula? state limitations

Answer 1

provides the simplest whole number ratio of atoms/ions of elements in a compound

*applies to both ionic and covalent compounds (?)
*doesn’t show actual no. of atoms in a compound

Question 2

what is a molecular formula?

Answer 2

gives actual no. of atoms of each element in a molecule
*sometimes empirical and molecular are the same e.g H2O
*doesn’t show the arrangement of atoms in a molecule

Question 3

what are compounds?

Answer 3

substances that contain more than one element

Question 4

can ionic compounds (eg calcium carbonate/NaCl) have molecule formula?

Answer 4

no, because not a molecule

Question 5

what are isotopes?

Answer 5

atoms of the same element with the same no. of protons but different no. of neutrons

Question 6

describe the 4 types of states

Answer 6

1. solid- particles aligned in a regular pattern/lattice
2. liquid- particles moving next to each other
3. gas- particles moving randomly/independently
4. aqueous- aqueous solution of a solute dissolved in water

Question 7

what is the symbol for density/commonly used unit?

Answer 7

• d
• g/mL
• kg/L