Law of conservation of matter lab report.The chemical reaction used to research is: AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
Chemistry Lab Report
Law of Conservation of matter
To design and perform a quick experiment to prove the Law of Conservation of matter.
Does the mass of the reactants before the experiment is same as the mass of the product formed? Does the mass of the matter stays conserved during a chemical reaction as stated by the Law of Conservation of Mass?
Law of Conservation of matter states that matter can neither be created nor be destroyed. According to this, there must be no loss in mass and particle of reactants after any physical or chemical reaction.
The chemical reaction used to research is:
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
We hypothesis that the total mass of the reactants would be equal to the mass of products formed. This is because according to the Law of conservations of mass, there must be no loss in the mass of reactants in any reaction. Therefore, no loss in the total mass of reactants would prove the Law of Conservation of matter.
The independent variable is the mass of the reactants. The dependent variable is the product produced and it’s mass. The controlled variables are the same reactants, same volumes and types of the containers (beakers or graduated funnel, etc), same analytical balance to weigh and the same concentration of the reactants.
The reactants that are being used for all trials are Silver nitrate solution and Sodium chloride solution, and we are using same volumes and types of beakers so that there is no change in mass and same analytical balance with uncertainty of ±0.1. To keep the concentration of the reactants same, we will make the whole solution first so that there is no change in mass or reactivity.
This is a preview of the whole essay
- 5ml of Silver nitrate solution
- 5ml of Sodium chloride solution
- Pipette of 10 ml
- 2 beakers of 50 ml.
- 2 Graduated cylinders of 100ml
- Analytical Balance to weigh the mass
- A small square piece of paper (4cm x 4cm) to weigh the solids
- 4ml of distilled water to make the solution
- A glass rod to stir
Some Safety Issues:
Tie back your hairs.
Be careful to not get the substances onto your skin.
Do not eat the substances.
Wear safety glasses.
Wear gloves while using any toxic chemical.
Making up the Sodium chloride solution:
- Take a 1 graduated funnel of 50ml and clean it properly with water and pour 5ml of distilled water in it.
- Take the small square piece of paper and place it on the Analytical Balance. Tare the balance (set it to zero). Carefully weigh 2 grams of Sodium chloride (Or table salt) on it.
- Now put the 2 grams of Sodium chloride into the graduated funnel of 100ml with 5ml of distilled water in it. Stir the mixture with a glass rod so that Sodium chloride mixes completely in the water.
Making up the Silver nitrate solution:
- Take a 1 graduated funnel of 100ml and clean it properly with water and pour 4ml of distilled water in it.
- Take the small square piece of paper and place it on the Analytical Balance. Tare the balance (set it to zero). Carefully weigh 1grams of Silver nitrate on it.
- Now put the 1 grams of Silver nitrate into the graduated funnel of 100ml with 4ml of distilled water in it. Stir it with a glass rod so that Silver nitrate mixes completely in the water.
- Weigh a beaker of 50ml (wash properly and dry it) using an Analytical Balance, but do not remove it from the balance after weighing and tare the balance (set it to zero).
- With a of pipette of 10ml (which is cleaned before with distilled water) measure out 5ml of solution of Sodium chloride by looking at top of the line horizontally, at eye level and slowly to ensure that the bottom of the meniscus is on the line of the pipette.
- Pour it in the beaker of 50 ml.
- Weigh 10 ml of Sodium chloride solution using Analytical Balance.
- Weigh a beaker of 50 ml(wash properly and dry it) using a Analytical Balance, but don not remove it from the balance after weighing and tare the balance(set it to zero).
- With a of pipette of 10mL (which is cleaned before with distilled water) measure out 5mL of Silver nitrate by looking at top of the line horizontally, at eye level and slowly to ensure that the bottom of the meniscus is on the line of the pipette.
- Pour the measured out 10mL of Silver nitrate into the weighed beaker of 50mL (wash properly and dry it)
- Pour the 5 ml of Sodium chloride solution into the beaker containing 5 ml of Silver nitrate.
- Now weigh the product formed using Analytical Balance.
When two solutions are mixed together, the color changes to white and afterwards it changes to pink and the mixture become cloudy which shows that there are some solid particles in it. The color of the mixture gradually changes to pinkish purple.
Table showing the mass of the Sodium Chloride solution in grams, mass of the Silver nitrate in grams, mass of the product formed in grams and the actual calculated mass of the product formed in grams during five trails of the reaction.
Average mass of the product formed, i.e., experimental yield ± 0.1= 59.2grams ±0.1
Average of the actual calculated mass of the product = 59.5grams
- Trail 1: 7.8+19.3=27.1
- Trail 2: 15.5+38.5=54
- Trail 3: 23.3+57.8=81.1
- Trail 4: 11.6+28.9=40.5
- Trail 5: 27.2+67.4=94.6
Average mass of the product formed, i.e., experimental yield ±0.1
= (27.0+53.9+81.1+40.3+94.6)/5=59.2 grams
Average of the actual calculated mass of the product
From the Table and the graph, we concluded that average mass of the product formed, which is 59.2 grams is less then the theoretical calculations of mass of the product, which is 59.5grams.
The mass of the product formed in Trail 1 is 27.0 grams, in trail 2 is 53.9grams, in Trail 3 is 81.1grams, in Trail 4 is 40.3 and in Trail 5 is 94.6grams. There is uncertainty of 0.1grams in all the trial.
By looking at the data table above you can clearly see that the two substances Sodium Chloride Solution and Silver Nitrate’s (total product formed when both liquids where added together) total mass of the product remained almost same. As you can see from the information of the data table above, trial 3 and 5 had the exact mass which was required. Trial 3: The mass of sodium 23.3 added together with the mass of silver nitrate 57.8 gave the total mass of 81.1. This was exactly the mass calculated. In the most cases the total mass of the product formed was nearly exact; however, there where slight differences of 1 or two grams. This experiment clearly proved the Law of conservation.
However, we know that during a chemical reaction total mass of the product formed does not change, but in this case there are little differences in the mass of the product formed and the calculated mass of the product. The gradient of line of best fit is 1.0024, which is approximately 1. So this shows that data collected is reliable.
The most likely cause of this error was the fact that the according to the procedure we had to mix two solutions by transferring the Sodium chloride solution from its beaker to the beaker containing Silver nitrate solution. When I transfer the Sodium chloride solution from its beaker to the beaker containing Silver nitrate, some Sodium chloride was attached on the beaker which didn’t come out. Though it changes the mass of the product very little but still there is a change which shouldn’t be there.
There are some uncertainties +/- 0.1g in weighing the product. These all factors might have affected the experimental yield. The temperature and pressure was not controlled as it was assumed that the experiment is conducted at room temperature but there might be some changes in temperature and pressure which might have influenced.
Realistic modification to the experiment that explicitly addresses the error(s)/weakness(s) that I identified:
The beakers, graduated cylinders and pipettes used must be cleaned properly. The proper caution should be taken while weighing the product and insure that there is no loss of product while weighing it and insure that reading on measuring balance is zero before you weigh it. Practice dropping water with dropper while preparing solution and ensure that the bottom of the meniscus is on the line and look horizontally, at the eye level. While it is necessary to transfer the content into another flask with filter paper in order to filter it, and therefore some loss of product is unavoidable, I do not think that the procedure made it clear just what impact this could have on the results. Therefore, in the future I think that this error could be minimized by placing an explicit warning in the procedure and by using the only solution to this problem would be to ensure that the lid is on the crucible and to carry it as carefully as possible to prevent the loss of the product.