» Unit 4 – Substances explore. more.

LEARNING OBJECTIVES

- Distinguish between pure substance and mixtures:
  - A pure substance has a definite set of characteristic properties (density, mp, bp), whereas a mixture exhibits properties that are a mixture of the properties of the substance they contain.
  - A pure substance is composed of one kind of particle, whereas mixtures contain more than one kind of particle.
- Describe how one could use differences in characteristic properties to separate the components of a mixture.
- Sketch particle diagrams that distinguish compounds, elements and mixtures.
- Distinguish elements from compounds in terms of differences in their properties.
- Cite the evidence that supports the belief that some pure substances are “compounded” of simpler particles in a definite ratio.
- Cite evidence for Avogadro’s Hypothesis. Use this with evidence from combining volumes to deduce the formulas of some compounds.
- State features of Dalton’s model of the atom; use composition by mass data to account for the laws of definite and multiple proportions.
- Describe the evidence that supports the idea that the simple particles have a property we call charge.
- Describe the evidence that led Thomson to suggest that the mobile charge in atoms is negative.
- Use the Thomson model of the atom to account for the fact that neutral atoms can become either positively or negatively charged by the loss or gain of electrons.
- Identify properties that distinguish metals from non-metals.
- Describe the evidence that distinguishes ionic from molecular or atomic solids.
- Given the formula of an ionic or molecular substance, state its name.
- Given the name of ionic or molecular substance, write its formula.
- From the name or formula of a substance determine whether that substance is ionic or molecular.