Chem

3. Analyze: What do you notice about the density of the Styrofoam pieces? The density remains the same.

because each of the objects displaced the water by 1 mL, their mass over that mL is their density.

Mole of chlorine : 1.0217g - .221g - .3946 g = .4061 g of chlorine

Purpose: Weighing objects. Figuring out the density with an object by calculated volume and Archimedes’ Principle.

5. Calculate the density of an object that has a mass of 43 g and a volume of 56.0 mL.

5. Calculate the mass of the water by subtracting “Mass A” from “Mass B.” Record the mass of the water in Data Table 4.

This experiment was performed to observe differences in density based on the chemical makeup of an object. Pennies minted before 1982, pennies minted after 1982, and an unknown metal sample was tested to see if there were any differences in their densities. Ten pennies from each category and the metal sample were weighed using a scale to find mass and the displacement method was used to find their volumes. The masses and volumes were then used to calculate the densities of the pennies (D=m/v). The density of the pre-1982 pennies were 8.6 g/mL while the post-1982 pennies were 6.9 g/mL. The metal sample’s density was 1.7 g/mL. Following the experiment we were given the real densities of each item to calculate the percent error with the formula

CHM130 Lab 6 Exploring Density Name A. Data Tables Place your completed Data Tables here Part IIIa (3 points) Volume of water in graduated cylinder (mL)10 mlMass of rubber stopper (g)11.15Volume of water and rubber stopper (mL)16.5 Part IIIb (6 points) Volume of water in graduated cylinder (mL)20Mass of iron nail (g)3.66Volume of water and iron nail (mL)20.5 Part IV (20 points) Type of Aluminum FoilMass (g)Length (cm)Width (cm)Volume (cm3)Thickness (cm)Regular.63g15 cm 10.02 cm.21 cm3.0014 cm Heavy Duty.97g15 cm10.01 cm .36 cm3.0024 cm B. Follow Up Questions Show all work for questions involving calculations. Part I Use the concepts/vocabulary of density to explain why the liquids formed layers in Part I of the procedure. (8 pts)

Introduction: Accuracy and precision were the major aspects of the lab. Accuracy is how close the average of the measured values are to the actual value. Precision is the closeness of repeated measurements. In the lab, the aim was to get as close as possible with both accuracy and precision when determining the mass and volume of the spheres. The mass was determined by weighing the spheres on the Analytical Scale and Triple Beam Balance Scale. The volume is determined by measuring with a ruler and by water displacement. The standard

The mass of salt (.26 grams) was then divided by the total mass of mixture (3 grams) and then multiplied by 100 to get 8.7% salt. The mass of sand was determined by subtracting the 100mL beaker with filter paper and sand (54.57 grams) by the the empty 100mL beaker with filter paper weighing 52.74 grams, to get 1.83 grams of sand. The mass percent of sand was determined by dividing the 1.83 grams of sand by the mass of mixture (3 grams) and multiplying by 100 to get 61%

4. A solid block of exactly 100.0 cm3 has a mass of 153.6 g. Determine its density. Will the block

In the third stage of this experiment, the density of a liquid was determined and compared to known standards. A 100ml beaker was filled to about half-full with room-temperature distilled water. The temperature of the water in ◦C was recorded in order to compare to known standards later. A 50ml beaker was then weighed on a scale in order to determine mass and recorded. A sample of the distilled water with an exact volume of 10ml was then placed in the 50ml beaker using a volumetric pipette. The 50ml beaker with the 10ml of water was then weighed again and the initial mass of the beaker was subtracted from this mass to obtain the mass of the 10ml of water. With the volume and the mass of the water now known, density was calculated using d = m/V and recorded in g/ml. This process was then repeated to check for precision and compared to standard values to check for accuracy. Standard values were obtained from CRC Handbook, 88th Ed.

It used mass, temperature, length, volume, density, and making a dilute solution. I learned the importance as well as the difficulty of making proper measurements in a lab setting. If one measurement is off, it will throw the entire equation off. This will give either incorrect or inaccurate results.

The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.

Furthermore, the measurements from a wooden block and a metal object were taken to calculate their volume and density. In this case, the calculations were more precise but due to other sources of errors, which may be systematic, random or personal, the data was not 100% accurate. There are always certain uncertainties associated with any type of measurement and it is important to know that no measurement will be one hundred percent correct.