You light up my life conductivity

Chem Catalyst If you were to drop a spoonful of salt (NaCl) and a gold ring into a glass of water and stirred for 2 minutes, what would happen to both substances? Why do these substance react so differently to water? Answer in terms protons, neutrons and/or electrons. Are atoms of gold, sodium and chlorine considered metals, nonmetals or metalloids?

The Big Question What patterns do we see in the properties of substances in relationship to the atoms that compose them? Unit 1 • Investigation V 3

You will be able to: Predict whether MgSO4(aq), epsom salts, will conduct electricity. Unit 1 • Investigation V 4

Two properties we will explore in this lab Conductivity Solubility in water

Define Conductivity Solubility

Build conductivity meters We use Christmas Tree lights with wires to form a conductivity meter

(cont.) (cont.) Unit 1 • Investigation V 8

Draw a sketch of set up in your comp book

Test Salt dry Mix salt and Distilled water Test mixture

Intro to electricity What is a circuit? Open vs closed circuit Short Circuit

Salt and saltwater demonstration Determine if Sodium chloride (Table salt) conducts electricity as a solid. Determine if Sodium chloride dissolves in water Determine if NaCl (aq) is a conductive substance

Revisit Mixtures and Substance change Amount of Solubility Homogeneous (H): Uniform Solution, can not determine separate ingredients Heterogeneous (He): Can determine ingredients, but some mixing occurs When water was added to create a solution: Was there a: Chemical change (C) (chemical reaction, evidence by bubbles or a change of color different from the substances dissolved)

Lab set up Form groups Make sure each member has their own copy of all handouts There are a number of stations around the room, groups will be rotating through them Groups will take their conductivity test equipment with them as they move through the stations

Why does something dissolve? The connections between molecules of the substance are broken It does not mean that the connections between the atoms that make up the molecule are severed.

Activity Purpose: This lesson allows you to collect evidence regarding the conductivity and solubility properties of certain substances, and look for patterns. (cont.) Unit 1 • Investigation V 16

Procedures to take at the stations Do not leave the conductivity meter connected in circuit too long. These Christmas light burn out very fast Do not connect wire to both ends of battery, creating a short (dangerous). This burns out the batteries extremely fast. Points will be deducted from group score for lab if this occurs Once you test the materials at a station take paper clips off of beaker and dry them off. Separate all material Do not place paper clips used to test one material or solution into a different one, (minimize Contamination)

Extra Lab Precautions Be aware about special conditions for the following materials: Ethanol (strong smelling) Calcium Chloride Solution (can damage paper clip, stain clothes) Copper Sulfate solution (can damage paper clip)

The solvent will be water for each solution

When Done Answer questions based on lab with your partner(s) Make sure your have cleaned up after yourself Question and answer session will follow

In Solid Form In aqueous form Mixture Type Hom , Het Chemical Change Solute Formula and Name Conduct? Dissolve? Potassium Chloride (KCl) Al(s) C12H22O11(s) Sugar NaCl(s) Salt SiO2(s) Sand C20H42(s) Parrafin wax NO Het No C2H6O(l) Ethanol XXXXXX(No) Cu(s) CaCl2(s), calcium chloride CuSO4(s), copper sulfate Tap Water (mixture) XXXXXXXXX Distilled H2O (l)

Most objects can be sorted into one of 4 categories: Whether it dissolves or not Whether it conducts or not

Notes Dissolves Yes No Conducts Conducts Yes No Yes No NaCl – salt CaCl2 – calcium chloride CuSO4 – copper sulfate KCl-potassium Cl H2O – water C12H22O11 – sugar C2H6O – ethanol Cu – copper Al – aluminum SiO2 – sand C20H42 – paraffin Unit 1 • Investigation V 23

Which elements in the chemical formulas of the solutes and solvents are: Metals Nonmetals

Elements in the solutes, solvents Metals Na Ca Cu K Al Non-metals (including metalloids) H O C S Si Cl

Conducts, dissolves Conducts, does not dissolve Dissolves, does not conduct Does not dissolve or conduct

Connections between type of element and whether the substance is soluble or conductive?

Why does something dissolve? The connections between molecules of the substance are broken It does not mean that the connections between the atoms that make up the molecule are severed.

Wrap-Up Not all substances conduct electricity or dissolve win water. Substances that do conduct electricity involve either solid metals, or metal-nonmetal compounds dissolved in water. Compounds that both dissolve and conduct require at least one metal and one non-metal element in the chemical formula. Unit 1 • Investigation V 29

Check-in Predict whether MgSO4(aq), epsom salts, will conduct electricity.