1. Distinguish between physical and chemical changes. Include examples in your explanations. 2. What are the differences among elements, compounds and mixtures? 3. Fill in the chart below to identify the properties of shape and volume for each type of matter. 4. Explain how atomic mass and molecular mass are determined. 5. Fill in the chart below to identify and describe the parts of an atom. 6. Identify the assumptions made as part of Dalton’s atomic theory.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.