Conservation Of Mass Lab
Conservation of Mass Lab
Author: Aubrey Bryant
Team Members: Elianna Chavez, Berkley BresemannDate of Experiment:
Date Report Submitted: September 30, 2014
Instructor: Josh GeisingerClass: Chemistry
Purpose:
The purpose of this experiment was to use the Law of Conservation of Mass and the Law of Definite Proportions to determine the quantity of zinc chloride that is produced in a chemical change from a given amount of zinc.
Background:
We used two important laws of chemistry in this lab. Firstly, the Law of Conservation of Mass states that matter is neither created nor destroyed during a chemical reaction and the mass of a system should therefore remain constant during any chemical process. In other words, the mass of any one …show more content…
element at the beginning of a reaction will equal the mass of that element at the end of the reaction (1). Secondly, the Law of Definite Proportions states that a chemical compound always contains exactly the same proportion of elements by mass. For example, if oxygen makes up 8/9 of the mass of pure water, then hydrogen must make up the remaining 1/9 of the mass (2). We used two main substances in this lab, zinc (Zn) and hydrochloric acid (HCI). Hydrochloric acid is a clear, colorless, highly pungent compound which is composed of a hydrogen atom and a chorine atom. It is highly corrosive and is known to break down many metals including aluminum, zinc, calcium, magnesium, and iron to generate flammable hydrogen gas (3). In these reactions, a colorless gas is emitted and the metal seems to disappear. This colorless gas produced in the reaction is hydrogen gas. Zinc is a silver gray chemical element which is dense, brittle, and solid at room temperature. We have previously seen the reaction between zinc and hydrochloric acid and therefore know it bubbles and breaks down the zinc. The formula representing the reaction of the two substances is as follows: Zn + 2 HCI = ZnCl2 + H2
This equation shows the law of conservation of mass, as there is the exact number of each element on each side of the equation, just in different forms. There is one zinc atom, two hydrogen atoms, and two chlorine atoms on either side. The zinc and hydrochloric acid react together to produce zinc chloride and hydrogen gas. The reaction also shows the law of definite proportions, as the zinc chloride will always result in a fixed ratio of the mass of one zinc atom to the mass of two chlorine atoms in the compound.
Based on this Law of Definite proportion, we determined a 1:2 ratio to find the percentage amount of zinc in ZnCl2.
Because this compound occurs in fixed proportions, for every one zinc atom, there are two chlorine atoms. The following formula can be used to determine the percentage of the mass of zinc chloride in zinc:
Mass of ZnMass of ZnCl2×100%=% mass of Zn (1)
The percentage of mass of zinc in ZnCl2 was then discovered by inserting the atomic massed of zinc and zinc chloride, which can be found on the periodic table, into formula 1.
65.39 amu65.39 amu+235.453 amu×100%=47.89% Zn According to these calculations, zinc should theoretically make up approximately 48% of the mass of ZnCl2.
In order to observe the law of conservation of mass and the law of definite proportions at work in this lab, we mixed zinc and hydrochloric acid, then we boiled the mixture to remove excess liquid which produced the compound zinc chloride. By altering formula 1, we predicted the amount of zinc chloride …show more content…
produced.
Mass of ZnCl2=mass of Zn 0.4789 (2)
Procedure:
Materials: flask scale powdered zinc, Zn hydrochloric acid, 4M graduated cylinder stirring stick hot plate oven mitt
First, we labeled our flask with our team name, Glitter Kittens.
Next, we measured and recorded the mass of our flask and then zeroed the scale. We then obtained a sample of zinc from our instructor and added it to the flask. Afterward, we measured and recorded the mass of the zinc and the flask. We calculated the mass of the zinc by subtracting the mass of the flask and the zinc from the mass of the flask by itself. Making sure it was between 0.8g and 1.15g. We carefully measured 10mL of 4M hydrochloric acid (HCI) in our graduated cylinder. This we then poured into the to the flask and recorded our observations such as sight and smells. We then set aside the flask and waited five days for the reaction to complete. When we returned to the flask after the five days, we made and recorded observations about the reactions which had taken place. We turned on our hot plate and set it to 275o C. We set the flask on the hot plate and waited for the liquid to begin to boil. We recorded our observations throughout this step until the liquid had completely evaporated. After the flask cooled down, we observed and measured the mass of the flask and its contents on a zeroed balance. We then recorded this data and cleaned the flask with
water.
Results:
Table 1 shows the quantitative measurements that were recorded.
Table 1. Quantitative measurements
Mass of Flask
(empty) Mass of Flask
(with zinc) Mass of Flask
(after boiled) Mass of Zinc Mass of Solid Zinc Chloride
69.75g 70.88g 72.18g 1.13g 2.43g
Before mixing the substances, the zinc was a dark gray, fine powder. The Hydrochloric Acid was a clear liquid. When the two substances first reacted, it he mixture began to fizz and bubble. We saw a white gas coming out of the flask and the flask heated up.
Discussion:
With the data collected throughout the experiment and the two laws stated in the background, the Law of Conservation of Mass and the Law of Definite Proportions, we were able to find the amount of zinc chloride produced from the combination of zinc and hydrochloric acid. To find this measurement, we used formula 1 and plugged in our measurements of zinc and zinc chloride.
1.13g2.43g×100%=46.50%We discovered that based on our calculations the amount of zinc chloride in the mixture was 46.50%. The actual measured percentage was 47.89% so our calculations were very close. Our percentage of error was 2.9% error. Our error was very low but the error that was present may have been caused by incorrect rounding when doing calculations. That is the only possible point of error in this experiment.
This experiment supports the law of conservation of mass because it shows that even though the zinc seemed to have disappeared, it simply changed forms. This is seen through the measurements we took throughout the experiment.
Conclusion:
Our results show that the percentage of zinc chloride produced through the chemical change of the combination of zinc and hydrochloric acid is 46.50% this was very close to our predicted percentage of 47.89% and gave us only a 2.9% error. In future experiments be careful when rounding measerments during the calculations, as this is where our error was most likely caused. References:
"The Conservation of Mass." Nature.com. Nature Publishing Group, n.d. Web. 28 Sept. 2014.
"Law of Definite Proportions." Princeton University. N.p., n.d. Web. 27 Sept. 2014.
"Hydrochloric Acid (Hydrogen Chloride)." EPA. Environmental Protection Agency, n.d. Web. 30 Sept. 2014.
Author: Aubrey Bryant
Team Members: Elianna Chavez, Berkley BresemannDate of Experiment:
Date Report Submitted: September 30, 2014
Instructor: Josh GeisingerClass: Chemistry
Purpose:
The purpose of this experiment was to use the Law of Conservation of Mass and the Law of Definite Proportions to determine the quantity of zinc chloride that is produced in a chemical change from a given amount of zinc.
Background:
We used two important laws of chemistry in this lab. Firstly, the Law of Conservation of Mass states that matter is neither created nor destroyed during a chemical reaction and the mass of a system should therefore remain constant during any chemical process. In other words, the mass of any one …show more content…
element at the beginning of a reaction will equal the mass of that element at the end of the reaction (1). Secondly, the Law of Definite Proportions states that a chemical compound always contains exactly the same proportion of elements by mass. For example, if oxygen makes up 8/9 of the mass of pure water, then hydrogen must make up the remaining 1/9 of the mass (2). We used two main substances in this lab, zinc (Zn) and hydrochloric acid (HCI). Hydrochloric acid is a clear, colorless, highly pungent compound which is composed of a hydrogen atom and a chorine atom. It is highly corrosive and is known to break down many metals including aluminum, zinc, calcium, magnesium, and iron to generate flammable hydrogen gas (3). In these reactions, a colorless gas is emitted and the metal seems to disappear. This colorless gas produced in the reaction is hydrogen gas. Zinc is a silver gray chemical element which is dense, brittle, and solid at room temperature. We have previously seen the reaction between zinc and hydrochloric acid and therefore know it bubbles and breaks down the zinc. The formula representing the reaction of the two substances is as follows: Zn + 2 HCI = ZnCl2 + H2
This equation shows the law of conservation of mass, as there is the exact number of each element on each side of the equation, just in different forms. There is one zinc atom, two hydrogen atoms, and two chlorine atoms on either side. The zinc and hydrochloric acid react together to produce zinc chloride and hydrogen gas. The reaction also shows the law of definite proportions, as the zinc chloride will always result in a fixed ratio of the mass of one zinc atom to the mass of two chlorine atoms in the compound.
Based on this Law of Definite proportion, we determined a 1:2 ratio to find the percentage amount of zinc in ZnCl2.
Because this compound occurs in fixed proportions, for every one zinc atom, there are two chlorine atoms. The following formula can be used to determine the percentage of the mass of zinc chloride in zinc:
Mass of ZnMass of ZnCl2×100%=% mass of Zn (1)
The percentage of mass of zinc in ZnCl2 was then discovered by inserting the atomic massed of zinc and zinc chloride, which can be found on the periodic table, into formula 1.
65.39 amu65.39 amu+235.453 amu×100%=47.89% Zn According to these calculations, zinc should theoretically make up approximately 48% of the mass of ZnCl2.
In order to observe the law of conservation of mass and the law of definite proportions at work in this lab, we mixed zinc and hydrochloric acid, then we boiled the mixture to remove excess liquid which produced the compound zinc chloride. By altering formula 1, we predicted the amount of zinc chloride …show more content…
produced.
Mass of ZnCl2=mass of Zn 0.4789 (2)
Procedure:
Materials: flask scale powdered zinc, Zn hydrochloric acid, 4M graduated cylinder stirring stick hot plate oven mitt
First, we labeled our flask with our team name, Glitter Kittens.
Next, we measured and recorded the mass of our flask and then zeroed the scale. We then obtained a sample of zinc from our instructor and added it to the flask. Afterward, we measured and recorded the mass of the zinc and the flask. We calculated the mass of the zinc by subtracting the mass of the flask and the zinc from the mass of the flask by itself. Making sure it was between 0.8g and 1.15g. We carefully measured 10mL of 4M hydrochloric acid (HCI) in our graduated cylinder. This we then poured into the to the flask and recorded our observations such as sight and smells. We then set aside the flask and waited five days for the reaction to complete. When we returned to the flask after the five days, we made and recorded observations about the reactions which had taken place. We turned on our hot plate and set it to 275o C. We set the flask on the hot plate and waited for the liquid to begin to boil. We recorded our observations throughout this step until the liquid had completely evaporated. After the flask cooled down, we observed and measured the mass of the flask and its contents on a zeroed balance. We then recorded this data and cleaned the flask with
water.
Results:
Table 1 shows the quantitative measurements that were recorded.
Table 1. Quantitative measurements
Mass of Flask
(empty) Mass of Flask
(with zinc) Mass of Flask
(after boiled) Mass of Zinc Mass of Solid Zinc Chloride
69.75g 70.88g 72.18g 1.13g 2.43g
Before mixing the substances, the zinc was a dark gray, fine powder. The Hydrochloric Acid was a clear liquid. When the two substances first reacted, it he mixture began to fizz and bubble. We saw a white gas coming out of the flask and the flask heated up.
Discussion:
With the data collected throughout the experiment and the two laws stated in the background, the Law of Conservation of Mass and the Law of Definite Proportions, we were able to find the amount of zinc chloride produced from the combination of zinc and hydrochloric acid. To find this measurement, we used formula 1 and plugged in our measurements of zinc and zinc chloride.
1.13g2.43g×100%=46.50%We discovered that based on our calculations the amount of zinc chloride in the mixture was 46.50%. The actual measured percentage was 47.89% so our calculations were very close. Our percentage of error was 2.9% error. Our error was very low but the error that was present may have been caused by incorrect rounding when doing calculations. That is the only possible point of error in this experiment.
This experiment supports the law of conservation of mass because it shows that even though the zinc seemed to have disappeared, it simply changed forms. This is seen through the measurements we took throughout the experiment.
Conclusion:
Our results show that the percentage of zinc chloride produced through the chemical change of the combination of zinc and hydrochloric acid is 46.50% this was very close to our predicted percentage of 47.89% and gave us only a 2.9% error. In future experiments be careful when rounding measerments during the calculations, as this is where our error was most likely caused. References:
"The Conservation of Mass." Nature.com. Nature Publishing Group, n.d. Web. 28 Sept. 2014.
"Law of Definite Proportions." Princeton University. N.p., n.d. Web. 27 Sept. 2014.
"Hydrochloric Acid (Hydrogen Chloride)." EPA. Environmental Protection Agency, n.d. Web. 30 Sept. 2014.