Density of a Metal Cylinder:



Name: _____________________________ Lab section: _______________

DETERMINATION OF DENSITY OF METAL CYLINDER:

MASS: Use a balance to obtain 3 mass readings of a metal cylinder. Include units and sig fig.

Mass = ____________, ____________, _____________ AVERAGE = ______________

VOLUME FROM LINEAR DIMENSIONS:

Using a metric ruler measure the height and diameter of the cylinder. Calculate the radius.

Height = _____________ Diameter = ________________ Radius = ______________

From Vol = Pi r 2 h calculate the volume of the cylinder. Report the volume in the correct significant figures and include units.

Volume = _______________cm3_

VOLUME FROM WATER DISPLACEMENT:

Place 15.0 mL R.O. water in a 25 or 50 mL.graduated cylinder. Use a disposable eyedropper to adjust the water level and to dislodge trapped air bubbles. Read the water level at the bottom of the meniscus to +/- 0.5mL. This is the initial reading. Record it below.

Tilt the graduated cylinder. Carefully place the metal cylinder in the graduated cylinder.

Record the water level to +/- 0.5 mL as the final reading. Calculate the volume of the metal cylinder. Include units and the correct significant figures in your values.

Final volume reading = _____________________

Initial volume reading = _____________________

Volume of metal cylinder = ___________________

DENSITY OF METAL CYLINDER:

Calculate the density of the metal cylinder from your data. Include the correct sig. figs and units.

Density = Mass / Volume from linear dimensions = ________________

Density = Mass / Volume from water displacement = _________________

Compare your calculated density values to known density values of metals (below).

Which element is the metal cylinder most likely composed of?

Metal ________________________ Known density = _________________________

Is density a chemical or physical property? _________________________(see textbook)

Known Density Values of Metals: (g / cm3)

Fe 7.86 Cu 8.96 Al 2.7 Pb 11.34 Sn 7.34

Ni 8.91 Ag 10.5 Au 19.3 Pt 21.4 Zn 7.13

Name: _____________________________ Lab section: _________________

WHY DO SOME PENNIES HAVE DIFFERENT MASSES?

The composition of a penny (known as a Lincoln cent) changed in 1982. Prior to 1982, pennies were made of 95 % Cu and 5 % Zn. After 1982, pennies were composed of only 2.5% Cu and 97.5 % Zn. Post 1982 pennies are more susceptible to corrosion and pitting.

Pennies dated 1982 could be either composition.

Density copper = 8.96 g/ cm3 Density zinc = 7.13 g/ cm3

The density values for pennies below indicate the change in the composition of the penny.

Density of Penny BEFORE 1982 = 8.87 g / cm3 AFTER 1982 = 7.18 g / cm3

Therefore, pennies prior to 1982 have a different mass than pennies after 1982.

This data can be used to determine the volume of a penny.

DETERMINATION OF THE VOLUME OF A PENNY

FIND MASS: Use a balance to obtain 3 mass readings of a penny. Include units and sig. fig.

Mass = ____________, ____________, _____________ AVERAGE = ______________

YEAR of the Penny ______________

Using the Density values for pennies (given above) and the measured mass, calculate the volume of the penny. Show your calculation. Circle your answer. Include units and sig. figs.

Explain 2 other methods that can be used to determine the volume of a penny.

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