Minerals and Acid Lab

Introduction In this lab you will be given 5 mineral samples, which you will test for acid reactivity.

Testable Question Do all minerals react to acid in the same way? Write a hypothesis that answers the above question using the “if… then… because…” format.

Hypothesis Example: If a mineral contains carbonate then it will effervesce when acid is applied to its surface because carbonates are basic (the opposite of acid) substances, which are reactive with acids.

Variables Manipulated Variable – What are you changing? Responding Variable – What are you measuring? Controlled Variable – What stays the same? Think of more than 2 things.

Variables Manipulated Variable – Mineral Sample Responding Variable – Reactivity of the mineral with acid Controlled Variables – Equal number of drops, temperature of acid, temperature of minerals, type of acid, minerals intact… can you think of more?

Procedures Good procedures summarize the steps in PRESENT TENSE as a set of numbered instructions. Each step is one thing to be done. What is being changed (the manipulated variable), what is being measured (the responding variable), and what is being kept the same (controlled variable) can be clearly identified. Identify what to record (remember units!). Include the tool that will be used to observe or measure with. Clearly state how many times to repeat trials/experiment. Does the procedure have logical steps? Can someone do your procedure without your help?

Now you try it. Work with your table group to come up with a set of procedures to test a set of 5 minerals for reactivity to acid. In addition to a simple yes or no. We want to measure how reactive each sample is. Include a step (or steps) to measure how reactive each sample is.

Materials 5 mineral samples Acid Dropper Timer Goggles

Class Procedures 1.Put on Goggles. 2.Apply 2 drops of acid to the surface of mineral sample #1 and start timer. 3.If the sample fizzes, continue timing until fizzing stops. Otherwise, stop timing. 4.Record time (if any) and observations in the data table.

Procedures Continued 5. Wipe off the mineral sample with a wet paper towel. 6.Repeat Steps 2-5 for mineral samples Repeat Steps 1-6 two more times. 8. Clean up as directed by your teacher and wash your hands.

Data Table Mineral Sample # Effervesce (Yes or No) Trial 1 Effervesce (Yes or No) Trial 2 Effervesce (Yes or No) Trial 3 Reaction Time (seconds) Trial 1 Reaction Time (seconds) Trial 2 Reaction Time (seconds) Trial 3 Average Reaction Time (seconds) Reactivity of Minerals to Acid