Basic Laboratory Techniques and Operations

 

BASIC LABORATORY TECHNIQUES AND OPERATIONS ABSTRACT The main purpose of this experiment is to familiarize ourselves with the tools and equipment inside the laboratory. The experiment trained us the basic skills in the proper handling chemicals and equipment, as well as the basic ways of measurement that we must know, such as getting the mass, volume, density, and temperature of an object. For computing the density, we used the geometric measurement method and the water displacement method. We also compared the theoretical and actual values of the density of the metal ball. We computed for the equivalent temperatures of the water in Celsius, Fahrenheit, and Kelvin.

INTRODUCTION Mass is defined as a measurement of the amount of matter in an object. It is determined by weighing, while volume and density is determined by using the following formulas: Volume = length x width x height Volume (cylinder) = pi x r^2 x height Volume (sphere) = pi/6(D^3) Volume (water displacement) = final volume – initial volume Density = mass/volume There are three temperature scales: Celsius, Fahrenheit, and Kelvin. The Celsius and Fahrenheit scales are more commonly used, while the Kelvin scale is the absolute temperature scale because the zero on the Kelvin scale is the lowest temperature that can be attained theoretically. The following formulas are used to convert from one scale to another (Chang and Goldsby, 2014) Celsius = 5/9(F-32) Fahrenheit = 9/5(C) + 32 Kelvin = C + 273.15 We also computed for the average density and the percentage error. Average density = total mass/total volume Percent error = (theoretical value-actual value)/theoretical value x 100

OBJECTIVES

  Be able to handle and use chemicals and laboratory equipment properly   able to compute the mass, length, volume, and temperature of a given object with accuracy Be able to present the t he data accurately, observing the rules of significant figures   Be

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  Be able to convert a unit to another unit properly (e.g. Celsius to Fahrenheit)

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MATERIALS AND METHODS Equipment: -Bunsen burner -test tube -test tube holder -water -triple beam balance -heating pad -Vernier calliper -graduated cylinder -beaker -thermometer -metal ball Procedure: 1.  Prepare the Bunsen burner. Place 5 mL water in a test tube and heat it over the flame. Record the time it takes to boil. Close C lose the air holes and do the same. O Observe bserve the changes in the color of the flame. 2.  Get a sample of a rectangular object. Measure its length, width, and height. Compute for its volume. 3.  Get a sample of a cylindrical object. Measure its height. Measure its diameter using a Ver Vernier nier Calliper. 4.  Weigh an empty 250 mL beaker using a triple beam balance. Using a 100 mL graduated cylinder, measure 50 mL of water, and place it in the beaker. Weigh the beaker. Calculate the mass and density of the water. Make two trials. t rials. Compute the average density and the percentage error. 5.  Measure the diameter of the metal ball using the Vernier Calliper. Weigh it using the triple beam balance. Calculate its volume and density. 6.  Pour 50 mL of water in a 100 mL graduated cylinder. Slowly drop the metal ball in the graduated cylinder and record the final volume of the water. water . Calculate the volume and density of the met metal al ball. 7.  Measure 50 mL of water and place it in a beaker. Measure its temperature. Heat the beaker and record its boiling temperature. Express it in Celsius, Fahrenheit, and Kelvin. Repeat using 75 mL of water.