density, accuracy and precision lab

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

Purpose: To become familiar with the International System of Units and common laboratory equipment and techniques. To learn how to determine volume, mass, length, and temperature of a wide variety of items. To learn how to calculate density and concentration of dilutions.

Density is the amount of matter per unit of measurement (Merriam-Webster. Merriam-Webster, n.d. Web. 26 Aug. 2016.). If water has a density of 1.0 g/mL and you place a substance with a density of 1.8 g/mL the substance will sink because it is denser than water. Density is often measured in g/cm^3 or g/mL because the formula for density is D=m/v.

E. What would happen if you dropped the object into the beaker while using the Archimedes’ Principle method instead of submerging the object?

If I fill up two different containers with different amounts of water, then I will be able to understand the density of the two different mass/volumes of two different containers.

To start off the lab we did simple measurements with two different rulers, both measuring in centimeters but had different amounts of divisions on the second one making its measurements more precise. The first item to measure was a 13 x 100 mm test tube, again using the two different ruler’s metric ruler A and metric ruler B. After recording the measurements with the accurate rounding, we did the same steps to measure the diameter of a watch glass and an evaporating dish.

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

2. In order to calculate the density of a solid or liquid sample, what measurements are needed?

In Measuring and Understanding Density, several experiments were performed to find density of regularly shaped objects, irregularly shaped objects, liquids and gasses. An additional experiment was done to find the specific gravity of a sampling of liquids. The purpose of the experiment was to provide a better understanding of density and to be able to extrapolate unknowns based upon these calculations. The experiments yielded data in keeping with Kinetic-molecular theory in regards to the density of water versus its temperature. Key measurements and formulae were also used to determine densities of metal and plastic objects as well as irregularly shaped rocks. It is possible to find the density of an object (be it liquid, gas or

D. A sample of gold (Au) has a mass of 26.15 g. Given that the theoretical density is 19.30 g/mL,

The volume of a small test tube and a thin-stemmed pipet were determined in this section of the lab. Water was poured into a small test tube until the water reached the very top edge of the test tube. The test tube was then emptied into a plastic 25 mL graduated cylinder and volume was measured and recorded into data table 3. A think-stemmed pipet was completely filled with water. Drops were carefully counted and emptied into the empty plastic 25 mL graduated cylinder until the water level reached 1 mL. The number of drops in 1 mL was recorded into data table 3. The thin-stemmed pipet had a total volume of 4 mL and that was also recorded into data table 3.

The purpose of this lab was for the student to get involved with his or hers new lab kit as well as being able to know, identify and use each other tools provided in the kit. Another key learning aspect of this lab is to teach the student how to measure properly the many units in the SI system. I will be using laboratory dilutions, measurements, and weights to then calculate using algebraic formula.

b) An empty beaker was weighted. Then, water was filled in the beaker. The temperature was recorded at uniform intervals.