Vernier Software & Technology

# Conducting Solutions

## Introduction

In this experiment, you will study the electrical conductivity of water and various water solutions. A solution can contain molecules, ions, or both. Some substances, such as sucrose (C12H22O11) and glucose (C6H12O6), dissolve to give a solution containing mostly molecules. An equation representing the dissolving of sucrose (table sugar) in water is:

${{\text{C}}_{{\text{12}}}}{{\text{H}}_{{\text{22}}}}{{\text{O}}_{{\text{11}}}}{\text{(s)}} \leftrightarrow {{\text{C}}_{{\text{12}}}}{{\text{H}}_{{\text{22}}}}{{\text{O}}_{{\text{11}}}}{\text{(aq)}}$

where (s) refers to a solid substance and (aq) refers to a substance dissolved in water. Other substances, such as calcium chloride (CaCl2), dissolve in water to produce a solution containing mostly ions. An equation is:

${\text{CaC}}{{\text{l}}_{\text{2}}}{\text{(s)}} \leftrightarrow {\text{C}}{{\text{a}}^{{\text{2 + }}}}{\text{(aq) + 2C}}{{\text{l}}^{\text{ - }}}{\text{(aq)}}$

Calcium ions are necessary for muscle contraction, mitochondrial activity, bone formation, and many other metabolic processes. Organisms may obtain minerals such as calcium from their water supply, since ions dissolve in water.

You will determine conductivity of the solutions using a computer-interfaced Conductivity Probe. The unit of conductivity in this experiment is microsiemens per centimeter, or µS/cm.

## Objectives

In this experiment, you will

• Write equations for the dissolving of substances in water.
• Use a Conductivity Probe to test the electrical conductivity of solutions.
• Determine whether molecules or ions are responsible for electrical conductivity of solutions.

## Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

### Option 2

You may also need an interface and software for data collection. What do I need for data collection?

## Agricultural Science with Vernier

See other experiments from the lab book.

 1 Introduction to Data Collection 2 Acids and Bases 3 Diffusion through Membranes 4 Conducting Solutions 5 Osmosis 6 Respiration of Sugars by Yeast 7 Reflection and Absorption of Light 8 Soil pH 9 Soil Salinity 10 Soil Temperature 11 Soil Moisture 12A Photosynthesis and Respiration (CO2) 12B Photosynthesis and Respiration (O2) 12C Photosynthesis and Respiration (CO2 and O2) 13 Transpiration 14A Cell Respiration (CO2) 14B Cell Respiration (O2) 14C Cell Respiration (CO2 and O2) 15 The Greenhouse Effect 16 Energy in Food 17A Enzyme Action: Testing Catalase Activity 17B Enzyme Action: Testing Catalase Activity 18A Lactase Action 18B Lactase Action 19 Oxygen Gas and Human Respiration 20 Biochemical Oxygen Demand 21 Animal Temperature 22 Lemon "Juice" 23 Ohm's Law 24 Energy Content of Fuels 25 Photovoltaic Cells 26 Wind Power 27 Watershed Testing 28 Interdependence of Plants and Animals 29 Biodiversity and Ecosystems

### Experiment 4 from Agricultural Science with Vernier Lab Book

#### Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.