08. Acid Pollution

(Ocean Champions)

This investigation assesses the following criteria:

B - Inquiring and designing

C - Processing and evaluating

Introduction

You are a chemist, part of a team investigating the increasing acidity of the oceans. You have been asked to see if the use of sodium hydroxide to neutralise weak acids in the ocean would be a suitable approach to help reduce the damage to the environment.

How to test the effectiveness of sodium hydroxide?

You should design a method that will allow you to:

i See how good a sodium hydroxide solution is at neutralising a standard (1.0 mol dm-3) acid solution, selecting a suitable indicator.

ii repeat this method to see if it is still suitable to use to neutralise low concentrations of acid.

• • Think about how you will ensure that the products of your neutralisation reaction are not more harmful to the environment than the chemicals you start with.

  • How will you know that your neutralisation reaction has occurred? Which indicator is going to be the most suitable one to use and why?

  • How will you assess the possible risks from carrying out your experiment and what safety precautions will your method require?

  • Can you use calculations to predict how much of each chemical you will need, and then can you test how accurate your experiment is?

  • You should carry out preliminary experiments and calculations in class to ensure that your plan will work.

Remember the following points:

· Don’t forget to be qualitative in your hypothesis if you can.

· Fully explain your choice of variables (independent/dependent/control).

· Make sure you plan to get sufficient data to test your hypothesis

· Make sure you label your graphs (if you have one) and have units on your tables.

· Mention any relationships you have found. Be quantitative.

· Draw an explained conclusion and link it back to your hypothesis. Cite your sources!

· Make sure to mention errors and how they could be reduced. (RELIABILITY)

· Evaluate whether the method you used was a good one or would a different method be better. (VALIDITY)

“Ocean Champions.” Ocean Champions, www.oceanchampions.org/ocean-acidification/. Accessed 18 May 2017.