Chemical Change Lab Report

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The question is, how does a physical or chemical change affect the mass of a substance within a closed system? To respond to this question, my group did a lab to determine whether or not the mass would change or not. Our lab was to have a plastic bag containing baking soda, then add a cup of vinegar and a block of clay to the mix. We made sure to weight every element separately and then add them up for our total mass of 31 grams before the reaction. During the reaction, as soon as the vinegar was poured in there was a gas produced, bubbles. We immediately knew it was a chemical change, then we added in the clay. The bag was very cold and the block of clay had gone from squishy to rock solid. After they were put together and the chemical reaction reduced and calmed down. One thing we did wrong was let out a little bit of air because the bag was not fully closed, in return, it messed up our weight. Our ending mass was 30 grams. We conducted our investigation this way because we wanted to easily find a way to prove that no mass can be created or destroyed in a reaction. The data we collected was the mass of the cup which …show more content…

Added mass (clay, baking soda, vinegar) was 31 while the final was 30. We left eh bag open a little to pour in the vinegar and a little of the air gas had time to escape. Those three signs are known as signals of when substances combine in a chemical change to form one substance (so we can prove our explanation was a chemical change). The Law of Conservation of Mass states that matter cannot be created or destroyed, supporting our claim that matter cannot change in a closed system. In our experiment the mass changed from the beginning and end, meaning that mass must have escaped. During our experiment was had to have the bag open for a second at the beginning giving the gas time to escape and with it, its mass. This caused the mass the be