Number Of Drops Of A Penny Lab Report

In this case, it's how many drops I can get onto a penny without the water spilling off. Controlled Variables: These are things that I keep the same throughout all of the experiments to make sure that my results are actually due to the changes in the independent variable, not some other random change you made. I used the same penny and dropper. Procedure:

Add RO water to the 25 ml volumetric flask up to the mark. Put stopper on the flask and shake it properly.

Add 3 more pennies to the 3 pennies on the scale (making it 6 pennies) then record the result.

I think that 0 drops of water will fit on the penny. I feel as soon as you will put a drop of water on the penny it won’t stay, it will spread and eventually spill onto the paper towel.

1.) Measure out 20ml out of the water and place it into a glass beaker

9.  I filled the pipette with the soapy water solution and began to start adding drops of the solution to the same penny, from the distance of ½ centimeter, at a rate of one drop per second.

After performing the experiment, the results were that copper pennies have a greater density and mass than the zinc pennies. These results supported my hypothesis of since copper has a greater density than zinc, then the copper pennies will have a greater mass than the zinc pennies. Some errors that occurred during this experiment are the non-precise measurement of the water and how some of the copper pennies had grime on them because they were old. This extra grime caused the mass of the pennies greater. A precise measurement of 15 mL of water and clean copper pennies would improve the experiment and the amount of errors would be

10. As described in problem 7, a procedure was developed to determine the percent zinc in post 1982 pennies. In that procedure 50 ml of an HCl was used to react (dissolve) all of the zinc in the penny. To ensure complete reaction, the solution contains twice as many moles of HCl that is actually needed. To determine the percent zinc in the penny, the excess (unreacted) HCl was titrated with NaOH. Determine the concentration of NaOH needed if you want to use approximately 25 mL of NaOH to titrate the excess HCl.

Thereafter I used a pipette to meticulously drop in water up to the 250ml mark.

the water when the timer went off. Final steps were to stack quarters on the center of the paper towel

Filled two bags with three-quarters of water and one with the salt solution by using the pipette and the pipette pump. Closed carefully with the thread and cut the excess of bag or thread, make sure they are completely sealed before placing them in the beakers. The beakers should be labeled with the crayon and with a pen write down in the paper towel the contents of each beaker and bags respectively to avoid confusions, in the following order. 1) Bag 1 will be filled with distilled water and beaker 1 will be filled with two-thirds of 10% NaCl solution. 2) Bag 2 will be filled with 10% NaCl solution and beaker 2 will be filled with two-thirds of distilled water.

Procedure: Cut top off 2 liter bottle and bottom off another. Fill the one without a top with water and put a

Dispense .5 mL water into the already weighed conical vial, replace cap and face insert on its down side.

8. Repeat step 7 with H2SO4, except that you should use a 10 mL graduated cylinder of H2SO4 and adding 15 mL water.

The independent variable for the experiment was the paper towels. The dependent variable was the absorbency and strength. The constants for the experiment were the size of the paper towels that were used, the amount of water, the size of the beaker, the size of the cylinder and the amount of the weight.