University:
Ball State University
Course:
CHEM 111 | General Chemistry 1
Academic year:

2023
Views:

346

Pages:

5
Author:

michelle kh.

Laboratory : Conservation L a w of Mass (Lavoisier's Law) Watch the paper burning reaction. At first glance we can see that the mass of ash resulting from burning is smaller than the mass of paper that is burned. Is burning paper accompanied by a reduction in mass? Antoine Laurent Lavoisier investigated the masses of substances before and after reactions. Lavoisier weighed the substances before they reacted, then weighed the products of the reaction. It turns out that the mass of the substance before and after the reaction is always the same. Lavoisier summed up his findings in a law called the law of conservation of mass: "In a closed system, the mass of matter before and after the reaction is the same". The changes in matter that we observe in everyday life generally take place in open containers. If the reaction results are in the form of gas (as in burning paper), then the mass of the substance that is left behind becomes smaller than the original mass. Conversely, if the reaction binds something from the environment (eg oxygen), then the result of the reaction will be greater than the original mass. For example, the rusting reaction of iron (iron binds oxygen from the air) is as follows. Iron which has a certain mass will react with a certain amount of oxygen in the air to form a new iron oxide compound (Fe2O3(s)) which has the same mass as the initial mass of iron and oxygen. Fe(s) + O2 (g) Fe2 O3 (s) Laboratory Group Task I. Title Basic Laws of Chemistry (Lavoisier's Laws) II. Basic competencies Discover the basic laws of chemistry through experimentation and communicating the application of the basic laws of chemistry through experiments. III. Tools and materials IV. Trial Procedure 1. One leg of the Y tube is filled with 2 mL of lead(II) nitrate solution, while the other leg is filled with 2 mL of lead(II) nitrate solution the other tube is filled with 2 mL of potassium iodide solution. Then close with plugged and weighed. 2. After that, the two kinds of solutions are mixed in a tilted Y tube. Record the changes that occur. Then reweigh the Y tube together contents. V. Experimental Data VI. Question 1. Is the mass before and after the reaction the same? 2. Is your conclusion based on the masses of the substances before and after reaction? 3. How does Lavoisier's law sound based on the experiment above?