Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Laws of conservation of mass
To verify the law of conservation of mass
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: Laws of conservation of mass
Introduction:
A balanced chemical equation has reactants and product that has to represent a formulae. The amount of each element, number needs to be the same on either side of the equation. (E.g., HCl(aq)+NaHCO3(s) reacts to produce NaCl(aq)+H2O(I)+CO2(g)). This helps us view the study of the Law of Conservation of Mass, and how it works in this equation.
The calculation for formula, mass helps us to determine if you need to convert grams to a particular substance to moles, from a product. Moles are numbers that are in front of formulae. E.g., 6NaCl(aq), 6 is the mole for this compound. A mole would help you balance a skeleton equation, and also allows you to calculate how many moles are needed to take part in a chemical reaction.
In the laboratory experiment, we are investigating the following equation and
…show more content…
how they react: HCl(aq)+NaHCO3(s) reacts to produce NaCl(aq)+H2O(I)+CO2(G) (Note*this chemical equation is already balanced on either side of the equation) When HCl(aq)+NaHCO3(s)reacts with each other, we would find the final product of how much NaCl(aq) would be produced in the end. Statement: How does the theoretical yield of the compound NaCl(aq) compare with the experimental (actual) yield? Hypothesis: If we mix HCl(aq) and NaHCO3(s) and CO2(g) fizzes in the meanwhile, then we can cook the solution and have H2O(l) to evaporate and leave NaCl(aq) as our final product. Materials: Refer to Mr.Papagapiou Relationship between Mole and Mass Laboratory, Revised November 2015 1. 5M hydrochloric acid (HCl(aq)) 2. Sodium hydrogen carbonate (NaHCO3(s)) -Materials that was changed -Instead of 6M hydrochloric acid (HCl(aq)), we used 5M Laboratory equipment’s: Refer to Mr.Papagapiou Relationship between Mole and Mass Laboratory, Revised November 2015 1. Electrical balance 2. Bunsen burner 3. Evaporating dish 4. Water glass 5. Scoopula 6. Beaker 7. Dropper pipette 8. Ring stand 9. Iron ring 10. Wire gauze 11. Safety googles -Materials not being used 1. Test tube (replaced by beaker) Procedure: 1. Flame-dry a clean evaporating dish by heating it in the part of the Bunsen burner for about 5 minutes. 2. Need to cool down all dishes. 3. Find the combined mass of the evaporating dish and the watch glass. This is (a) in the list of data. 4. Leaving the watch glass and evaporating dish on the electronic balance, measure an additional 3.50g, of sodium hydrogen carbonate (NaHCO3(s)) to the evaporating dish. Record the mass as (b) in the list of data. 5. Set up the ring stand, ring and wire gauze. Place the watch glass on top of the evaporating dish and place the dish on the wire gauze. 6. Obtain approximately 5ml of 5M hydrochloric acid (HCl(aq)) in a dry beaker. a. Obtain 5M of HCl(aq) in a clean dry beaker. Need to handle acid carefully. b. Using a dropper pipette, slowly add HCl to the NaHCO3in the evaporator dish, a few drops at a time. Add the acid until the reaction stops bubbling. c. Tilt evaporating dish back and forth a couple of times, to make sure that the acid has contacted all the NaHCO3 d. Make sure bubbling is stopped, remove the watch glass and place it curved side up on the lab bench 7. Light the Bunsen burner and gently heat the evaporating dish. Use a low flame and move the burner back and forth to avoid being splattered. When almost all liquid is has evaporated, remove the burner and replace the watch glass on the evaporating dish, leaving a small opening for vapour to escape. Heat gently again, until no liquid remains. 8. Compute the combined mass of the watch glass, evaporating dish, and contents (NaCl) 9. Record data for mass -Procedure that was changed: 1. Obtain approximately 6M hydrochloric acid (HCl(aq)) in a dry beacker. -instead of 6M hydrochloric acid, we used 5M Conclusion: Overall to conclude, the data shows that in this chemical equation HCl(aq)+NaHCO3(s) reacts to produce NaCl(aq)+H2O(I)+CO2(G), we are focusing only on NaHCO3(s) and NaCl(aq). We need to be precise when getting the grams of the products. The data shows that the evaporating dish+watch glass is 158.7g, then later adding the NaHCO3 came up to 162.2g. After cooking the solution, everything came up to 160.5g. 160.5g is an important number for our date because this helped us discover that when you subtract 160.5g by 3.50g of the NaHCO3(s) that was given, we got 1.8 as an actual yield for this experiment. The mole ratio is 1:1 ratio and in this lab we are mainly focusing on how much NaCl(aq) is produced when all the water is evaporated in a solution.
In the data (Q2) shows that we have approximately 0.0416mols of NaCl(aq), and also approximately 0.0416 of NaHCO3. In the end the yield for NaCl(aq)(product), we got was 3.077%. This percent is lower because of the incident that acquired during the lab. Which leads to possible errors that can happen during the lab. The percent was lower them hundred percent was because of the spill of the solution that happen while working on the lab. We lost a lot solution which affected the amount of mole for NaCl(aq) and the yield drastically from looking at the calculation. Another possible error can be when you are cooking the solution and didn’t get to evaporate all the water that is still visible in our eye, it can cause your calculation to be incorrect and less product you are looking for in the end. Last error can be when the electrical balance can malfunction during your experiment or it doesn’t work or possibly broken. These are some of the possible errors that can happen in the lab that can affect the data
analysis. This application can relate to the real world because we use certain liquids to find what they produce. For example coke, when you boil coke in heat, the liquid would start evaporating eventually. In the end results are the amount of sugar one coke bottle that was put in to this soft drink. Another example of a real life connection is rice. When rice is cooked, some of the water is absorbed into the rice and the rest of the water is evaporated. This relates to the lab that we have to boil the water to make sure the water is evaporated leaving the product behind. You have to use a certain amount of water for a certain amount of rice to cook properly. Last example is when you cook any soups, you use water and other ingredients. Some of the water evaporates while cooking and it leaves behind a ring around the bowl, which are products that were left behind when the water is at a process of evaporating. These are some of the examples of real life connections. In the end our hypothesis (If we mix HCl and NaHCO3 and CO2 fizzes in the meanwhile, then we can cook the solution and have H2O to evaporate and leave NaCl as our final product.) is acceptable. From looking at the data we are looking for NaCl of how much moles and yield that were produced. Therefore this lab was successful even though we made a mistake for spilling the solution (Sorry Mr.P) and that our data illustrated those procedures doing the lab.
Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.
In this experiment there were eight different equations used and they were, molecular equation, total ionic equation, net ionic equation, calculating the number of moles, calculating the theoretical yield and limiting reagent, calculating the mass of〖PbCrO〗_4, calculating actual yield, calculating percent yield (Lab Guide pg.83-85).
For example, a balanced chemical equation of a certain reaction specifies that an equal number of moles of two substances A and B is required. If there are more moles of B than of A, then A is the limiting reactant because it is completely consumed when the reaction stops and there is an excess of B left over. Increasing the amount of A until there are more moles of A than of B, however, will cause B to become the limiting reactant because the complete consumption of B, not A, forces the reaction to cease. Purpose
The Gravimetric Stoichiometry lab was a two-week lab in which we tested one of the fundamental laws of chemistry; the Law of Conservation of Mass. The law states that in chemical reactions, when you start with a set amount of reactant, the product should theoretically have the same mass. This can be hard sometimes because in certain reactions, gases are released and it’s hard to measure the mass of a gas. Some common gases released in chemical reactions include hydrogen, carbon dioxide, oxygen and water vapor.
Thorough analysis of the graph displayed enough evidence suggesting that an increase in substrate concentration will increase the height of bubbles until it reaches the optimum amount of substrate concentration, resulting in a plateau in the graphs (figure 2). Hence; supported the hypothesis.
Also, looking at Table 1, the percent yield is shown to be 44.9%. The percent yield is how much product was recovered after the reaction was carried out. The percent yield can be used to explain why the melting point observed in the experiment didn’t match the known melting point. Obtained melting points are generally lower than the literature value melting points of a substance due to the number of impurities present in the obtained product. The percent yield of 44.9% validates that the product could have had some impurities present, and thus the lower melting point.
This graph shows that as enzyme concentration increases absorption also increases. In this case absorbance can be used to measure the enzyme’s activity, the higher the absorption the higher the activity. Since absorption increases as enzyme concentration increases, enzyme activity is promoted by increased enzyme concentrations. After a certain point enzyme activity would fail to increase as a result of increased enzyme concentration since there wouldn’t be enough substrate for all of the enzymes to react with.
“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].
The equation shows how 1 mol of Na2CO3 reacts with 1 mol of H2SO4, so
According to the graph on amylase activity at various enzyme concentration (graph 1), the increase of enzyme dilution results in a slower decrease of amylose percentage. Looking at the graph, the amylose percentage decreases at a fast rate with the undiluted enzyme. However, the enzyme dilution with a concentration of 1:3 decreased at a slow rate over time. Additionally, the higher the enzyme dilution, the higher the amylose percentage. For example, in the graph it can be seen that the enzyme dilution with a 1:9 concentration increased over time. However, there is a drastic increase after four minutes, but this is most likely a result of the error that was encountered during the experiment. The undiluted enzyme and the enzyme dilution had a low amylose percentage because there was high enzyme activity. Also, there was an increase in amylose percentage with the enzyme dilution with a 1: 9 concentrations because there was low enzyme activity.
Unit 7: Chemical Reactions: Students will understand the basic concepts of reactions, bonding, the “mole” and how this relates to the law of conversion of matter.
Experimental error is something that always occurs, no matter how hard one tries to prevent it. One situation where error might have occurred would be in the mixing of the water and Pb(NO3)2 and mixing of the water and NaI solutions. The solids were not fully dissolved into the water and when mixed, the yellow solution had all the precipitate at the bottom of the beaker while the clear liquid remained at the top. The mixed solution was still all yellow in color but not all of it was the same shade of yellow. This might have impacted the experiment by producing more PbI2 than it was supposed
One possible source of experimental error could be not having a solid measurement of magnesium hydroxide nor citric acid. This is because we were told to measure out between 5.6g-5.8g for magnesium hydroxide and 14g-21g for citric acid. If accuracy measures how closely a measured value is to the accepted value and or true value, then accuracy may not have been an aspect that was achieved in this lab. Therefore, not having a solid precise measurement and accurate measurement was another source of experimental error.
Stoichiometry is a chemical branch that studies amounts of substances that are involved in reactions. Stoichiometry will help you to find out how much of the mixture you will need, or how much you started with. The calculations of a stoichiometry problem depends on a balanced chemical equations. The factors of the balanced equations signifies the molar ratio (the number of moles of each reactant needed to form a certain numbers of moles of each product) of the reactants and products taking part in the reaction. From the atomic and molecular point of view the stoichiometry in a chemical reaction is very simple. For example, one mole of oxygen reacts with two moles of hydrogen,
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.