Friday, 2/10/17

Success Criteria I can follow directions. I can work cooperatively with my peers. I can handle equipment correctly. I can keep the product away until I get home (or teachers will take it!) I can show proof of the Law of Conservation of mass.

#24. Goop Lab! Goop Lab! Matter can not be created or destroyed. It changes form through chemical reactions. Today we are going to show that the mass of the materials we start with (reactants) will be the same as the mass of the materials we end with (products).

1. Using a ruler and a permanent felt tipped marker, make a mark 1/2 inch from the bottom on the outside of the baggie. Fill the baggie to the mark with white glue. This will be about 25 ml. 2. Using a graduated cylinder, measure out 25 ml of water and add it to the glue in the baggie. Stir well. 3. Using a beaker, measure out 15-20 ml of sodium borate solution: pour it into the cup. The glue solution and sodium borate solution are the reactants.

Find the combined mass of the reactants by placing the cup with the sodium borate solution and the baggie with the glue solution on the scale at the same time. Record the combined mass. 5. Pour the sodium borate solution into the plastic baggie. Seal the baggie and knead the mixture for a few seconds. Make and record observations.

Remove the solid material from the bag Remove the solid material from the bag. As you remove the solid material from the bag, hold the solid over the bag for a few seconds to allow any liquid to drip back into the bag. 7. Reseal the bag and set it aside. Work the material with your hands until it forms a “Silly Putty”-type solid. Experiment with this material and record observations of its special properties. The solid material and the liquid left in the bag are the products of this chemical reaction.

Find the combined mass of the products by placing the bag with the remaining liquid, the “Silly Putty”-type solid, and the cup on the scale. (Make sure you understand that it is necessary to weigh the cup because its mass was included when the sodium borate was weighed.) Record the mass. Compare the combined masses of the reactants and the products. Record what you have learned. ***Finally, make sure your name is on your baggie and your paper. Materials manager will turn-in everyone’s paper at your group.