The more concentrated the hydrochloric acid is, the faster the reaction will take place.

        We are trying to find the effect of different concentrations of hydrochloric acid and if this affects the rate of reaction.  We will use marble chips and different levels of concentration to help us find if this is the case.  

Prediction:

        I think that the more concentrated the hydrochloric acid is, the faster the reaction will take place.  The more concentrated the hydrochloric acid is, the more dense the substance will be, and therefore, there will be more particles per centimetre cubed.  Because of the density of the hydrochloric acid the particles have more of a chance of colliding with each other.  And because there are more collisions in this denser hydrochloric acid there is a higher chance of the particles sticking and forming new bonds.  

I predict that the less dense the hydrochloric acid is the longer that it will take for the reaction to finish.  This is because the less dense hydrochloric acid doesn’t have as many particles as the dense hydrochloric acid there is less chance of the particles colliding and therefore there is less chance for the creation of new bonds.

I believe if we heat up the hydrochloric acid the reaction will take place more quickly because there is more kinetic energy meaning that the particles are moving around at a greater pace and there is more of a chance for the particles to collide, stick, and form a new bond.  I think that the larger the surface area, of the marble is the faster that the reaction will take place.  So for example if we use marble clumps for the reaction than the reaction will take longer than if we use marble powder.  

Range of Measurements

        We will use a decreasing amount of concentration, of the Hydrochloric acid, as the experiment proceeds.  We will do this by filling the given amount up with hydrochloric acid and than fill the rest of the space if any space with water depending on what stage of the experiment we are at.   We have five different amounts of concentrations that we have chosen to use.  We will start out with a 100% concentration of hydrochloric acid, which will have the quickest rate of reaction.  We will than decrease in concentration by 20% each time we perform the experiment.  We will do reaction in twenties all the way down to 20% concentration where the reaction will take place the slowest.  The time that it will take for the reaction to finish will lengthen as the concentration decreases.

Apparatus

 

• Scale
• Flask
• Test tubes
• Stop clock
• Spatula
• Goggles
• Tub
• Glass Pipe with cork

 

Safety:

• Wear goggles
• Make sure work area is clean
• Clean up mess with paper towels
• Tuck all stools under the desk
• Take care with the glass flask

Method

1. In step one; we will collect all the apparatus we need to perform the experiment.
2. Measure into a glass flask 5 grams of marble chips
3. We then fill up a test tube with water, to the brim.  I place my thumb over the top of the test tube so no water will escape when we tip it upside-down.
4. We then place the test tube in a tub that is filled with water. (I do not remove my thumb from the top of the test tube until the test tube is under the water.
5. We measure out a given amount of water and a given amount of Hydrochloric acid into one test tube.
6. We then pour the hydrochloric acid and the water in to the flask with the marble chips inside of it.
7. We place a cork with a glass pipe (which runs into the test tube in the tube), over the flask. (So that all the gas that is released from the reaction will be transported to the tub with the test tube.)
8. We use a stopwatch to find out how long it takes for the gas to reach the 20cm3 mark.
9. Once the gas reaches this point we stop the clock and write down our results on a piece of paper.

10) We than repeat the exact same experiment with the exact same measurements one more time.

RESULTS:

Analysis

Justification

        We have tried three different ways in which to measure the experiment.  We tried the process of weighing, gas syringe, and downward delivery.  We ended up choosing download delivery because it was the most accurate for us and was quite easy to set up, I also thought it was a bit more sophisticated in how it worked.  

We decided after repeating the downward delivery process a few times with different amounts of hydrochloric acid and marble chips that we would use 5 grams of marble chips and 25 cm3 of hydrochloric acid.  We started out using 10 gram’s of marble chips and 50 cm3 of hydrochloric acid but the reaction took to long (it took 4.10 minutes).  So we tried a smaller amount of marble chip for the second time.  Finally on our last attempt we were satisfied with the rate of reaction.  We halved the amount of hydrochloric acid and we halved the amount of marble chips we used and in the end ended up with a good result.

        We chose powered marble chips instead of rocks because the reaction would happen faster because powdered marble chips have more surface area than the rocks at the same weight.  And therefore there is more marble surface area for the hydrochloric acid to react with.  To make sure that this was a fair test we will try to choose marble chips of the same size so that the surface area is the same for each marble chips.

        We are using the room temperature for the experiment because it is the most efficient way.  The only problem is that we have to do the experiment on the same day so the temperatures will be the same during all the testing.  

        We found out that if you hold the test tube side ways while collecting the gas it will not give you an accurate result, but if you hold the tube straight it will give an accurate result.

To make sure that this was a fair test we will measure the hydrochloric acid and water carefully.  We will make sure that there is no excess air in the test tube in the water so that we get an accurate reading.

To measure accurately we will use a stopwatch and measure to the nearest 100th of a second.