Purpose:

Practicing determine the density of the solution.

Developing the method for determine the percent of density for the solution.

Examining the linear relationship by learning to use the best-fit straight line.

Using the linear relationship to determine the percent of density by the solution.

Be familiar with recording data and observations.

Methods & Material:

Methods:

Weight the mass for the different percent of zinc and copper mixtures, which have 11 groups.

Determining the volume of the zinc and copper mixtures each, and record the data.

Using equation get the density of the pennies. Compare the results.

Find the best-fit straight line.

Material:

0%Cu—100%Cu

0%Zn—100% Zn

5, 10, 20, and 30 pre 1982 pennies.

5, 10, 20, and 30 post 1982 pennies.

Graduated Cylinder

Procedure:

Weight the mass of the different percentages of zinc and copper mixtures.

Determining the volume of the different percentages of zinc and copper mixtures.

Weight the mass of the pennies and record the data.

Put the pennies (5, 10, 20, 30) into the mixtures; determine the volume of the pennies.

Record the data into the table.

Repeat the step 1-5. At least three times.

Using the data from before created a graph.

Using the graph, get the best-fit straight line to examine the relationship.

Using the predicative model (the best-fit line) to determine the percent copper and zinc in pennies.

Then accuracy the errors and error percentages.

Precision the absolute deviation and the deviation percentages.

Observation:

Part 1: Pre-82 Pennies

Weight 10 dry pre-82 pennies which get 30.29g, using 30ml initial volume measuring the volume of 10 pennies, record the data 3.0ml. Using equation Density= Mass/Volume, get the density of the pre-82 pennies is 10.10g/ml. Then calculate the error%=0.23%, and the deviation%=11.03%.

Weight 20 dry pre-82 pennies which get 50.89g, using 30ml initial volume