Lab - The Disappearing X Rate of Reaction Activity

Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
Lab - The Disappearing X Rate of Reaction Activity
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812 KB|10 pages
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  1. Save Over 25%! This unit bundle contains 23 resources needed for a typical middle school chemistry unit on chemical reactions. The bundle contains a unit PPT and corresponding student summary notes, worksheets, lab activities, formative quizzes, review exercises, a PPT unit review game, and summat
    Save $18.00
Product Description
This 10-page rate of reaction lab activity gives students experience in measuring the rate of reaction between sodium thiosulfate and hydrochloric acid while changing the concentration of sodium thiosulfate.

In this chemical reaction, the two reactants are clear, colorless liquids, which are combined in a clear beaker or conical flask placed on top of a piece of white paper with a black ”X” drawn in the middle of it. As the two reactants are combined, one of the products is solid sulfur, which turns the clear, colorless solution a cloudy opaque yellow color as more and more of it is produced. Eventually, the black “X” disappears from view. This provides students a simple chemical timing mechanism to determine the rate of the reaction.

After performing a guided serial dilution of sodium thiosulfate and conducting the experiment, students graph their data and explain their findings using ideas found in collision theory.

NOTE 1: This Activity is Modified From a More Advanced Lab to Suit 8-9th Grade Students

This activity is also called “The Disappearing Cross Lab” in many countries, particularly in the UK, and is typically performed in higher chemistry classes with more a more advanced dilution series and a less directed format. I personally find the lab exciting, engaging and easy to understand, so I took a more advanced lab procedure and modified it to suit the knowledge and learning needs of 8th – 9th grade students.

NOTE 2: This Lab Also Available as a Virtual Simulation!

If time or materials are an issue, this lab activity has an equivalent virtual version that uses a computer simulation (Flash) to gather all data. The link to this product is found below.

Lab - The Disappearing X Rates of Reaction Activity (Virtual Lab)

Product Contents:

Page 1 – Introduction to the Experiment:
- Outlines the chemical reaction, provides the equation, and discusses how to measure the rate of reaction
- Problem statement
- Hypothesis
- Materials list

Page 2 – Pre-Lab Worksheet:
- Introduction to performing a basic serial dilution
- Dilution table for calculating the 5 concentrations of sodium thiosulfate (as %) prior to the lab
- Identifying variables: independent variable, dependent variable and 3 relevant constants

Page 3 – Procedure, Data Table, and Graph Grid:
- Detailed procedure for conducting the lab based on the 5 concentrations from the pre-lab worksheet
- Blank data table for recording reaction times
- Blank graph grid for creating a graph of average reaction time vs. concentration

Page 4 – Analysis & Conclusion:
- 3 analysis questions that ask students to summarize their data, explain their findings using collision theory, and discuss reliability of results if certain variables were not kept constant
- 1 conclusion question that asks students to summarize the entire investigation in a concise way

Pages 5-8 – Answer Keys:
- 4 pages of color-coded answer keys
- Includes sample student data and sample graphs to use with students
- Includes answer to all analysis and conclusion questions

Pages 9-10 – Teacher Guide:
- A detailed, 2-page teacher’s guide that discusses important aspects of the experiment
- Summarizes the main ideas of collision theory, particularly the effect of concentration
- Gives a suggested time frame to complete the lab and possible modifications
- Offers tips on how to prepare for the 2 solutions, including concentrations and volumes
- Provides advice on how to conduct the lab safely and efficiently on the day of activity
- Describes common sources of errors and how to minimize them in a troubleshooting section

Downloadable in 2 Formats:

This worksheet comes in 2 formats: a static PDF document and fully-editable WORD document

Download the full PDF preview to see EXACTLY what you are getting!

Relevant NGSS Core Idea(s) Addressed by This Product:

Physical Science - Matter and its Interactions - Structure and Properties of Matter

Physical Science - Matter and its Interactions – Chemical Reactions

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Copyright © Douglas Enns. All rights reserved by author. This product is to be used by the original downloader only. Copying for more than one teacher, classroom, department, school, or school system is prohibited. This product may not be distributed or displayed digitally for public view. Failure to comply is a copyright infringement and a violation of the Digital Millennium Copyright Act (DMCA). Clipart and elements found in this document are copyrighted and cannot be extracted and used outside of this file without permission or license. Intended for classroom and personal use ONLY.
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