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2. laboratory measurements


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2. laboratory measurements

  1. 1. Technological Institute of the Philippines 938 Aurora Blvd., Quezon City Experiment no. 2 Laboratory Measurements Submitted By: Group No.2 of Section ES11FB4 MEMBERS TASK PERFORMANCE TIME IN TIME OUT LAB GOWN (X/√) SIGNATURES OF MEMBERS Davis Banoog 1:30 4:30 Jenny-Ann Cabrera 1:30 4:30 Luis Miguel Benitez 1:30 4:30 Date Performed: July 05, 2013 Date Submitted: July 27, 2013 Engr. Renato Agustin Professor
  2. 2. OBJECTIVES: 1.1To be able to measure objects using the metric scale and convert the measurements into English scale. 1.2To be able to appreciate the usefulness of measurements in Chemistry. APPARATUS AND MATERIALS: 1 Bunsen burner 1 Match 1 beaker 1 thermometer 1 wooden block Wire gauze Ruler Stones Platform balance Iron stand Watch glass Graduated cylinder
  3. 3. THEORY: Chemistry as a quantitative science requires knowledge of measurement. Two systems of measurements are often using in scientific studies- the metric systems and the English system. The metric system or international system of measurement is now popularly being used. In system of measurement, it is important to distinguish between the physical quantities and the units of measurements. The following are the seven fundamental units of measurements: length (meter), mass (kilogram), time (second), electrical current (ampere), temperature (Kelvin), amount of substance (mole), and luminous intensity (candela). Accuracy refers to the closeness of measurements to the accepted value for a specific quantity. On the other hand, precision is the agreement among several measurements that have been made in the same way. Measurement of physical quantity is always subject to some degree of uncertainty that can be attributed to three factors; the researcher, the method and the instrument. The degree of uncertainty can be express in term of accuracy. It is express as either absolute relative error. | EV-AV | AV 100AE
  4. 4. PROCEDURE: 1. Measurement of Physical Quantities 1.1 Secure from the laboratory technician the above listed objects. Measure the objects in metric scales and convert the measurements into English scale. Use the table for your data. 1.2 Make three trials of measurements for each object and get the average values. 1.3 Round off your answer to three decimal places. 1.4 Record the date measured on the table provided the next page. 1.5 Show your solution. 2. Length (diameter) 2.1 Get a watch glass then mark its 2 opposite sides, passing through the center. 2.2 Using a ruler, measure the distance between the two points. That is the diameter. Record it as T1. 2.3 Repeat steps 2.1 and 2.2 using two more pairs of opposite points. This will serve as T2 and T3. Take the readings accurately and record on the table. 3. Volume of a Liquid 3.1 Measure 25mL of water in beaker and record the volume. 3.2 Transfer the liquid to a 50mL graduated cylinder. Record the volume 4. Area and Volume 4.1 Get a wooden block measures its length and width. Solve for the area. 4.2 Proceed to the measurement of height. Solve for the volume. 5. Mass and Density 5.1 Weight the wooden block and record its mass. 5.2 Solve for the density of the wooden block using the volume obtained in procedure 4. 6. Density of an irregular solid 6.1 Weight a stone and record its mass. 6.2 Measures 25mL of water using a graduated cylinder. Record its initial volume. 6.3 Drop the stone along the side of the graduated cylinder. Record the final volume. 6.4 Get the volume of the stone. (Final Volume – initial Volume = Volume of Stone) 6.5 Solve the density of the stone. 7. Temperature 7.1 Set up the apparatus as shown. 7.2 Pour 50mL of water in the beaker. 7.3 Get the initial temperature of water and record it on the table. 7.4 Bring the water into the boiling and record the final temperature.
  5. 5. OBSERVATION: DATA AND RESULTS: ANALYSIS AND INTERPRETATION: OBJECT MEASURED PHYSICAL QUANTITIES T1 T2 T3 AVERAGE Watch Glass Diameter cm 10 9.9 10 29.9 Inch 4 4.7 4 12.7 Water Volume (mL) Beaker 25 25 25 75 Graduated Cylinder 22 22 22 66 Wooden block Area cm2 50 50 50 150 in2 8 8 8 24 Wooden Block Volume cm3 2.500 2.500 2.500 7.5 in3 0.020 0.020 0.020 0.06 Wooden Block Mass G 19.2 19.2 19.2 57.6 Lb 0.042 0.042 0.042 0.027 Stone Mass G 4 4 4 12 Lb 0.009 0.009 0.009 0.027 Water Volume (mL) Initial 22 22 22 66 Final 23 23 23 69 Stone Volume (final-initial) 1 1 1 3 temperature °C 69 85 90 244
  6. 6. Conclusion: Boiling point is a physical property. Boiling point is used by scientist to identify unknown liquids because each liquid has a slightly different boiling point. Another reason scientists use boiling point is because you don’t have to change the chemical formula to find the boiling point. This makes the boiling point unique and specific to each substance. We used water in the lab to heat the liquids. Because water has a boiling point of 100°C, we could not find the boiling point of any substance that has a boiling point over 100°C. To measure the volume (cm3) of the wooden block you need to multiply the length, width and the height. To measure the volume of the rock which is irregular in shape we used the water displacement method. The water displacement method is a technique used to measure the volume of objects by calculating how much water it displaces, or pushes aside when it's placed into a sample of water. You determine the volume by subtracting the volume of the water without the object from the new measurement with the object - it will be the difference between the two. Typically it's done in a graduated cylinder or other measuring device you can more easily determine the difference.