Marquez, GabePrado, AngelMilicevic, PavleKeulinde, TobiTiffany CulverCHEM 1315-07716 October 2013

Heat Laws Systems Lab D-S: System 5

I. Introduction/Purpose

The purpose of the qualitative experiment is to use the temperature change of water upon the addition of various metals in order to determine if the metal is endothermic or exothermic. A quantitative determination will then be performed on the heat produced by adding a known mass of brass, zinc, aluminum, lead, copper, or iron to water using the temperature change of the water (T), the mass of the water (m), and the specific heat of the water (Cs=4.18 J/gC). The heat produced (q) will be found using the equation q=m Cs T and data will be collected for various masses of each metal. The theoretical heat of the reaction and the specific heat capacity of each metal should be able to be predicted by using the information found from the change in temperature and the mass of each reactant metal.

II. Procedure/Experimental Setup

The goal of this experiment is to be able to distinguish the differences in each metal by appearance, mass, density, specific heat, temperature change, and heat produced.

Materials

1 pair of goggles 1 ring stand 1 thermometer clamp 1 50 mL beaker 1 10 mL graduated cylinder 1 thermometer 1 polystyrene cup 1 stirring rod 1 pair of test tube tongs Various samples of brass, zinc, aluminum, lead, copper, and iron

Method

Put on safety goggles to ensure safety.

Obtain the various samples of lead, copper, and iron. Record and describe the appearance of each metal. Accurately weigh the samples of brass, zinc, aluminum, lead, copper, and iron on the analytical balance. Record the exact mass.

Obtain about 5 mL of distilled water in a 10 mL graduated cylinder. Insert the metal and record the volume displacement. Repeat this process for each metal.

Using the data from the mass (m) and volume of each metal, determine the density of each metal.

Suspend a thermometer into a polystyrene cup so that it is about inch from the bottom by using the ring stand and thermometer clamp. Using a volumetric cylinder, add 50.0 mL of distilled water and record the initial temperature.

At a separate station, give your metal sample to the TA to heat in a beaker filled with boiling water. After a few minutes, obtain the metal sample by using tongs and placing the metal into an empty beaker. Place the metal into the polystyrene cup filled with water. Record the final temperature of the system. Repeat this process for each metal.

By using your data, determine the change in temperature (T) from the initial and final temperatures of the water and metal. From this data, determine the amount of heat (q) produced from the system by using the equation, q=m Cs T. (The specific heat (Cs) of water is 4.18 J/gC).

Determine the specific heat (CS) of each metal by using the equation: q=m Cs T .

III. Data

See Table.

IV. Data Analysis

See Table and attached handwritten equations.

Density = mass/volume

Specific Heat of metal = (Mass of water * Specific Heat of water * Change in Temperature of water) / (Mass of metal * Change in Temperature of metal)

% Error = (actual theoretical) / theoretical * 100%

V. Conclusion

By using the equation, q=m Cs T, we were able to determine the heat of the reaction (q) and the specific heat capacity (Cs) of each metal.

The errors seen in the calculation of density may be due to water splashing out of the graduated cylinders, causing a miscalculation in displacement. The error seen in the calculation of specific heat may be due to the large mass of water used in the experiment. The difference between the masses of the metal and water made it more difficult to accurately calculate the change in temperature of the system.

Through this experiment, we were able to distinguish between the six metals by using different forms of data such as appearance, mass, density, specific heat, temperature change, and heat produced.

1. Brass2. Copper3. Lead4. Zinc5. Aluminum6. Iron

Work Cited

1. Metals Specific Heats. Metals Specific Heats. N.p., n.d, Web. 15 Oct 2013 2. Metal Alloys Specific Heats. Metal Alloys Specific Heats. N.p., n.d, Web. 15 Oct 2013 < http://www.engineeringtoolbox.com/specific-heat-metal-alloys-d_153.html>