Conservation of mass lab
Firstly, the Law of Conservation of Mass states that matter is neither created nor destroyed during a chemical exaction and the mass of a system should therefore remain constant during any chemical process. In other words, the mass of any one 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 (Zen) 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: Zen + 2 HCI = zincs H2O 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 exult 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 Zincs.
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 Zamias of mass of Zen (1) The percentage of mass of zinc In Zincs was then discovered by inserting the atomic eased of zinc and zinc chloride, which can be found on the periodic table, into 1 OFF calculations, zinc should theoretically make up approximately 48% of the mass of Zincs.
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 produced. Mass of zincs=mass of Zen 0. 4789 (2) Procedure: Materials: flask scale powdered zinc, Zen hydrochloric acid, MM 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. G and 1. 1 g. We carefully measured ml of MM 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 2750 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 lolled down, we observed and measured the mass of the flask and its contents on a zeroed balance.