Chemistry Lab Write-Up free essay sample

To demonstrate how changing the temperature at which a reaction takes place affects the rate of the reaction, the reaction between calcium carbonate and 1. 0 M hydrochloric acid will be observed at 5 various temperature readings. The 5 varying temperatures are targeted towards being at 10? C, 20? C, 30? C, 40? C, and 50? C. It is highly improbable that each trial for each of the 5 different temperatures will be the exact temperature that was targeted, so it’s just important that you end up having a temperature fairly close to the targeted temperatures so that the rates of reactions that you do receive are as correct as possible. The rates of reaction will be obtained using an apparatus that will guide the carbon dioxide gas being produced from the reaction between the 1. 0 M hydrochloric acid and the calcium carbonate from a reaction chamber into a flask containing water. This experiment will be performed by placing about 3. 0 grams of calcium carbonate chips into a flask containing 35 mL of 1. 0 M hydrochloric acid at one of the targeted temperatures. This flask is called the reaction chamber because it is the flask that contains the actual occurring reaction. The reaction between calcium carbonate and hydrochloric acid creates carbon dioxide as one of its products. When the carbon dioxide goes through the tube connected to the plug that seals the reaction chamber it enters the flask containing the water the water will be pushed up a different tube and will displaced into a 50 mL graduated cylinder where you can measure how long it takes for the water to be displaced up to a certain mark on the graduated cylinder using a stopwatch. In this specific experiment you will measure how long it takes for 15 mL of water to be displaced by the carbon dioxide gas being produced from the actual reaction. Background: The rate of a chemical reaction is inversely related to time. This means that the longer a reaction takes, the lower its rate. Rate can either be measured by the increase of product concentration divided by the time taken to achieve that concentration or by the decrease of reactant concentration divided by the time taken to reach that concentration of reactant (An Introduction to the Collision Theory in Rates of Reaction). The collision theory states that a chemical reaction is dependent on the collisions between reacting molecules (An Introduction to the Collision Theory in Rates of Reaction). But, for a reaction to occur, these molecules must collide in the correct orientation and they must collide with sufficient energy to be able to overcome the activation energy needed for a reaction to take place (An Introduction to the Collision Theory in Rates of Reaction). Factors that have an effect on the rate of a reaction include the concentration of reactants at the beginning of a reaction, the surface area of the reactants, pressure at which the reaction held, the use of a catalyst, and the temperature at which a reaction is held(An Introduction to the Collision Theory in Rates of Reaction). Increasing the concentration of the reactants at the initiation of a reaction increases the rate of the reaction because as the concentration increases, the frequency of successful collisions between reacting particles increases as well (Ford 123). Therefore, lowering the concentration of the reactants decreases the rate of the reaction. Decreasing the particle size, or increasing the surface area of the reactants increases the rate of the reaction because by subdividing the reactants you allow for more of the reactant to be exposed and that will lead to higher probability that the reactants will collide and react(Ford 124). Increasing the pressure will increase the rate of reaction, only if the reactants are in a gaseous form because increasing the pressure will decrease the volume which will then increase the concentration of the gases and lead to more successful collisions(Ford 124). The use of a catalyst will always increase the rate of a reaction because it provides a lower activation energy for a reaction to undergo successfully (Ford 124-25). Temperature affects the rate of a reaction immensely. Increasing the temperature will increase the rate of all reactions because temperature is a measure of the average kinetic energy of the particles and so the higher temperature represents an increase in their average kinetic energy (Ford 123). This also means that there will be a larger amount of particles exceeding the activation energy needed to collide successfully and react; this translates into an increase in the rate of the reaction (Ford 123). Many reactions tend to double their reaction for every 10? C increase in their temperature (The Effect of Temperature on the Rates of Reaction). But, by lowering the temperature at which a reaction takes place you lower the rate of reaction just as much as you increase the rate when you increase the temperature. Being able to control the temperature at which a reaction takes place is important because by being able to control the temperature you are also able to control the rate at which reactions happen, but most importantly you are able to control how fast you yield the product from the reaction. For example, in the Haber Process the product that is being produced is ammonia (The Haber Process for the Manufacture of Ammonia). By using a low temperature the equilibrium of the solution shifts to the right and yields more product, but using too much of a low temperature and the reaction will take an extraordinarily long time to create ammonia as a product. To solve this problem pressure and concentration of reactants are increased in order to be able to use a higher temperature so that the rate of the reaction is high, yet still produces a good amount of ammonia (The Haber Process for the Manufacture of Ammonia). In this experiment the reaction between 1. 0 M hydrochloric acid and calcium carbonate will be studied. The equation for the reaction between these two substances is: CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O(l) The calcium carbonate reacts with the hydrochloric acid in order to produce calcium chloride, carbon dioxide, and water. In this experiment the rate of the production of the carbon dioxide will be indirectly measured through the timing of how long it takes for 15 mL of water to be displaced. But, if we are measuring how long it takes for 15 mL of water to get displaced into the 50 mL graduated cylinder we are also measuring how long it takes for 15 mL of carbon dioxide gas to displace the 15 mL water into the 50 mL graduated cylinder. Hypothesis: If the temperature at which the reaction between 1. 0 M hydrochloric acid and calcium carbonate increases, then the rate of the reaction between the 1. 0 M hydrochloric acid and calcium carbonate will increase as well. According to the collision theory, if the temperature at which any reaction is held is increased then the rate of that reaction will always increase (An Introduction to the Collision Theory in Rates of Reaction). Temperature is a measure of the average kinetic energy of the particles and so a higher temperature represents an increase in their average kinetic energy (Ford 123). This also means that there will be a larger amount of particles exceeding the activation energy needed to collide successfully and react; this translates into an increase in the rate of the reaction (Ford 123). But, temperature and the rate of a reaction are directly proportional. If you increase the temperature of a reaction the rate will increase as well, but if you decrease the temperature the rate will decrease too. Variables: Independent Variable: The temperature at which the reaction between 1. 0 M hydrochloric acid and calcium carbonate is held is the independent variable because it is the only variable that is being altered during the experiment. In the experiment we change the temperature of the 1. 0 M hydrochloric acid before the calcium carbonate is added for the reaction to proceed to 5 different temperatures. The 5 varying temperatures are to be approximately: 10? C, 20? C, 30? C, 40? C, and 50? C. We are able to change the temperature of the 1. 0 hydrochloric acid by emerging the 500 mL Erlenmeyer Flask containing the 35 mL of hydrochloric acid into cold or hot water baths. By changing the temperature of the 1. 0 hydrochloric acid, the temperature at which the calcium carbonate and the hydrochloric acid react is able to be changed and we are able to observe how the temperature at which a reaction between 1. 0 M hydrochloric acid and calcium carbonate affects the rate of the reaction. Dependent Variable: The rate of the reaction between the 1. 0 M hydrochloric acid and the calcium carbonate is the dependent variable because it is the variable that is being affected by the changes in the independent variable, which in this experiment is the temperature at which the reaction is held. By changing the temperature at which the reaction is held you will either increase or decrease the rate, depending on whether you increased or decreased the temperature at which the reaction is held. To measure the rate of the reaction between the 1. M hydrochloric acid and the calcium carbonate, we will time how long it takes for the CO2 gas that is produced from the reaction between the hydrochloric acid and the calcium carbonate to displace 15 mL of water. To displace the water and measure the amount of time it takes to displace it we will use a water displacement apparatus that will allow us to take the carbon dioxide gas produced to enter a water chamber and displace the water from that chamber into a 25 mL graduated cylinder, and we will use a stopwatch to time how long it takes for 15 mL of water to be displaced. Controlled Variables: 1) The concentration and amount of hydrochloric acid used should remain consistent throughout the entire experiment. Therefore you should only use 1. 0 M hydrochloric acid and only use 35 mL of it when conducting a reaction with calcium carbonate. To make sure your hydrochloric acid is of the same concentration every time you conduct a reaction, use the hydrochloric acid from the same source every time, and to make sure you use 35 mL for every trial use a 50 mL graduated cylinder to measure the amount of hydrochloric acid before you place it into the 500 mL Erlenmeyer Flask. It is important to use hydrochloric acid with the same concentration throughout the entire experiment so that the rate of the reaction between the hydrochloric acid and the calcium carbonate isn’t affected by anything other than the temperature. If hydrochloric acid is of a higher concentration than 1. 0 M, Â  then the rate of the reaction will be faster than it should be, but if you use a hydrochloric acid with a concentration lower than 1. M then the rate of the reaction will be slower than it should be. 2) The amount of water being displaced should be consistent throughout the entire experiment, therefore you should time only how long it takes to displace 15 mL of water. To measure that you are timing how long it takes to displace 15 mL of water, use a 25 mL graduated cylinder. To get the most accurate rates as possible, start the stopwatch after you place the calcium carbonate into the 500 mL Erlenmeyer flask containing the 1. M hydrochloric acid at one of the 5 targeted temperatures and you have sealed the flask with the cork, then stop the stopwatch as soon as you see the water being displaced reach the 15 mL mark on the 25 mL graduated cylinder. 3) The amount of calcium carbonate used throughout the experiment should remain constant, so you should use 3. 0 grams every time you perform a reaction between the calcium carbonate and the 1. 0 M hydrochloric acid. To make sure that you are using approximately 3. 0 grams of calcium carbonate in every experiment performed use a weighing balance to measure out the calcium carbonate. It is important to use 3. 0 grams of the calcium carbonate in every experiment because if you use more than 3. 0 grams then more carbon dioxide gas will be produced and the rate will increase because water is being displaced faster because of the excess amount of calcium carbonate. But, if you use less than 3. 0 grams of calcium carbonate then the rate will be slower than it should be. METHOD Materials: 500 mL Erlenmeyer Flask 300 mL Erlenmeyer Flask 2 corks (plugs for that fit the 500 mL and 300 mL Erlenmeyer Flasks) Rubber Tubing 25 mL Graduated Cylinder 50 mL Graduated Cylinder Weighing Balance Weighing Paper Stopwatch Calcium Carbonate Chips 1. 0 M Hydrochloric Acid 2 Glass Bowls Thermometer Heating Plate 400 mL Beaker Water Ice Procedure: Setup: Using the 500 mL Erlenmeyer Flask, 300 mL Erlenmeyer Flask, the rubber tubing, the 2 corks, and the 25 mL graduated cylinder make a water displacement apparatus like the one displayed in the diagram below. [pic] 2. Fill up the 300 mL Erlenmeyer Flask up to the 250 mL with water before each trial of the experiment is conducted. The larger 500 mL Erlenmeyer Flask is the reaction chamber in which the 1. M hydrochloric acid will be placed to react with the 3. 0 grams of calcium carbonate chips. The 25 mL graduated cylinder is where the water will be displaced into as the carbon dioxide gas enters the water chamber from the reaction chamber and displaced the water. Make sure to dispose of the water displaced into the 25 mL graduated cylinder after each trial. Experiment: Reaction at 10? C Set up an ice bath by putting ice and water into the glass bowl and set it aside so you can cool the hydrochloric acid later in the experiment. Using a clean 50 mL graduated cylinder, measure out 35 mL of 1. M hydrochloric acid and then place the measured out hydrochloric acid into the 500 mL Erlenmeyer Flask and set the flask with the 1. 0 M hydrochloric acid into the ice bath. Stick the thermometer into the hydrochloric acid and wait until the temperature of the hydrochloric acid drops to about 10? C. While waiting for the temperature of the 1. 0 hydrochloric acid to drop, use the weighing balance to measure out 3. 0 grams of calcium carbonate. First, place a piece of weighing paper on th e balance and tare it. After you have tared the weighing paper, measure out the 3. 0 grams of calcium carbonate. Put the calcium carbonate aside until you are ready to react it with the 1. 0 M hydrochloric acid. Swirl the 1. 0 hydrochloric acid in the ice bath until it reaches 10? C. If your temperature goes below 10? C, take the Erlenmeyer Flask with the hydrochloric acid out of the ice bath and wait for the temperature to go up to 10? C. Record the exact temperature of the hydrochloric acid in the 500 mL Erlenmeyer Flask. Once the temperature of the 1. 0 hydrochloric acid is about 10? C, place the 3. 0 grams of calcium carbonate into the 500 mL Erlenmeyer Flask containing the 1. 0 M hydrochloric acid at 10? C and cork it and start the timer. Stop the timer once 15 mL of water is displaced from the water chamber into the 25 mL graduated cylinder. Record the amount of time it took for the water being displaced to reach the 15 mL mark on the 25 mL graduated cylinder. Set up the water displacement apparatus for the next trial. Repeat steps 2-7 4 more times until you have done a total of 5 trials for the rate of the reaction between 1. 0 M hydrochloric acid and calcium carbonate at 10? C. Reaction at 20? C Set up an ice bath by putting ice and water into the glass bowl and set it aside so you can cool the hydrochloric acid later in the experiment. Using a clean 50 mL graduated cylinder, measure out 35 mL of 1. 0 M hydrochloric acid and then place the measured out hydrochloric acid into the 500 mL Erlenmeyer Flask and set the flask with the 1. 0 M hydrochloric acid into the ice bath. Stick the thermometer into the hydrochloric acid and wait until the temperature of the hydrochloric acid drops to about 20? C. While waiting for the temperature of the 1. 0 hydrochloric acid to drop, use the weighing balance to measure out 3. 0 grams of calcium carbonate. First, place a piece of weighing paper on the balance and tare it. After you have tarred the weighing paper, measure out the 3. grams of calcium carbonate. Put the calcium carbonate aside until you are ready to react it with the 1. 0 M hydrochloric acid. Swirl the 1. 0 hydrochloric acid in the ice bath until it reaches 20? C. If your temperature goes below 20? C, take the Erlenmeyer Flask with the hydrochloric acid out of the ice bath and wait for the temperature to go up to 20? C . Record the exact temperature of the hydrochloric acid in the 500 mL Erlenmeyer Flask. Once the temperature of the 1. 0 hydrochloric acid is about 20? C, place the 3. 0 grams of calcium carbonate into the 500 mL Erlenmeyer Flask containing the 1. 0 M hydrochloric acid at 20? C and cork it and start the timer. Stop the timer once 15 mL of water is displaced from the water chamber into the 25 mL graduated cylinder. Record the amount of time it took for the water being displaced to reach the 15 mL mark on the 25 mL graduated cylinder. Set up the water displacement apparatus for the next trial. Repeat steps 10-15 4 more times until you have done a total of 5 trials for the rate of the reaction between 1. 0 M hydrochloric acid and calcium carbonate at 20? C. Reaction at 30? C Fill up a 400 mL beaker of water and heat it up until boiling on a hot plate. After it starts boiling place the water into the glass bowl. Using a clean 50 mL graduated cylinder, measure out 35 mL of 1. 0 M hydrochloric acid and then place the measured out hydrochloric acid into the 500 mL Erlenmeyer Flask and set the flask with the 1. 0 M hydrochloric acid into the water bath. Stick the thermometer into the hydrochloric acid and wait until the temperature of the hydrochloric acid increases to about 30? C. While waiting for the temperature of the 1. 0 hydrochloric acid to increase, use the weighing balance to measure out 3. 0 grams of calcium carbonate. First, place a piece of weighing paper on the balance and tare it. After you have tared the weighing paper, measure out the 3. grams of calcium carbonate. Put the calcium carbonate aside until you are ready to react it with the 1. 0 M hydrochloric acid. Swirl the 1. 0 hydrochloric acid in the water bath until it reaches 30? C. If your temperature goes above 30? C, take the Erlenmeyer Flask with the hydrochloric acid out of the water bath and wait for the temperature to g o down to 30? C. Record the exact temperature of the hydrochloric acid in the 500 mL Erlenmeyer Flask. Once the temperature of the 1. 0 hydrochloric acid is about 30? C, place the 3. 0 grams of calcium carbonate into the 500 mL Erlenmeyer Flask containing the 1. 0 M hydrochloric acid at 30? C and cork it and start the timer. Stop the timer once 15 mL of water is displaced from the water chamber into the 25 mL graduated cylinder. Record the amount of time it took for the water being displaced to reach the 15 mL mark on the 25 mL graduated cylinder. Set up the water displacement apparatus for the next trial. Repeat steps 17-23 4 more times until you have done a total of 5 trials for the rate of the reaction between 1. 0 M hydrochloric acid and calcium carbonate at 30? C. Reaction at 40? C Fill up a 400 mL beaker of water and heat it up until boiling on a hot plate. After it starts boiling place the water into the glass bowl. Using a clean 50 mL graduated cylinder, measure out 35 mL of 1. 0 M hydrochloric acid and then place the measured out hydrochloric acid into the 500 mL Erlenmeyer Flask and set the flask with the 1. 0 M hydrochloric acid into the water bath. Stick the thermometer into the hydrochloric acid and wait until the temperature of the hydrochloric acid increases to about 40? C. While waiting for the temperature of the 1. 0 hydrochloric acid to increase, use the weighing balance to measure out 3. 0 grams of calcium carbonate. First, place a piece of weighing paper on the balance and tare it. After you have tared the weighing paper, measure out the 3. grams of calcium carbonate. Put the calcium carbonate aside until you are ready to react it with the 1. 0 M hydrochloric acid. Swirl the 1. 0 hydrochloric acid in the water bath until it reaches 40? C. If your temperature goes above 40? C, take the Erlenmeyer Flask with the hydrochloric acid out of the water bath and wait for the temperature to g o down to 40? C. Record the exact temperature of the hydrochloric acid in the 500 mL Erlenmeyer Flask. Once the temperature of the 1. 0 hydrochloric acid is about 40? C, place the 3. 0 grams of calcium carbonate into the 500 mL Erlenmeyer Flask containing the 1. 0 M hydrochloric acid at 40? C and cork it and start the timer. Stop the timer once 15 mL of water is displaced from the water chamber into the 25 mL graduated cylinder. Record the amount of time it took for the water being displaced to reach the 15 mL mark on the 25 mL graduated cylinder. Set up the water displacement apparatus for the next trial. Repeat steps 25-31 Â  4 more times until you have done a total of 5 trials for the rate of the reaction between 1. 0 M hydrochloric acid and calcium carbonate at 40? C. Reaction at 50? C Fill up a 400 mL beaker of water and heat it up until boiling on a hot plate. After it starts boiling place the water into the glass bowl.