Week 3 SLG 4.5.1 - Mass of Matter PDF

Nature of Science - Measurements LESSON 4.5.1 Mass of Matter (Solids Time Limit: 30 mins and Liquids) At the end of this learning, you should be able to determine the mass of solids and liquids. TA...

Nature of Science - Measurements LESSON 4.5.1 Mass of Matter (Solids Time Limit: 30 mins and Liquids) At the end of this learning, you should be able to determine the mass of solids and liquids. TA 1 min AT When buying sugar or rice in a grocery or in a “sari-sari” store, the mass is usually expressed in kilogram (kg). In a doctor’s prescription, medical doctors usually prescribe tablets or capsules expressed in milligram (mg), like 500-mg of Mefenamic acid. The image below shows the Nutritional Facts of a pack of chocolate chip cookies. What can you observe on the amount per serving of the different nutrients and contents? _____________________________ TA 3 mins AT Figure 4.5.1.1. Nutritional Facts of a Chocolate Chip Cookies These units that we are using in our daily lives are the same units of measure we use in measuring mass of a substance. The concept of mass was already introduced in Learning Guide 4.2, and we will discuss more about it in this Learning Guide. Mass is a basic property of matter. It is a fundamental quantity of measurement. Can you still remember what is mass? Mass is the measure of the amount of matter an object contains. The SI (International System of Units) unit of mass is kilogram (kg). In the laboratories, scientists measure small quantities of chemicals or solutions and use gram (g) or milligram (mg) instead of kilogram (kg). Pound (lb), an TA 12 mins English unit of measurement, is also used for measuring mass. One-kilogram (1.0-kg) is equal to about 2.2 pounds (2.0-lb). AT Mass of an object is constant regardless of location and the gravitational force applied to the it. Learning Guide 4.5.1 page 1 of 9 MEASURING THE MASS OF MATTER Mass is measured using a balance. There are different types of balance used in the laboratory. These balances are triple beam balance, digital balance, and analytical balance. A triple beam balance is a single pan balance used to measure the mass of an object precisely. This tool got its name from three long, horizontal metal bars called beams connected to a pointer on the right side. The rear beam has 100 g scale with a 10 g rider, the middle beam has 500 g scale with a 100 g rider and the front beam has 10 g scale with a 0.1 g rider. Figure 4.5.1.2 shows other parts of a triple beam balance. Figure 4.5.1.2. The different parts of a triple beam balance Another device used in measuring mass accurately and precisely is the analytical balance. It records measurement between 0.1 mg to 0.01 mg. The capacity of commonly used analytical balance is 100 g and mass of substance greater than its capacity will cause damage. This type of balance is sensitive. Shown in Figure 4.5.1.3 the basic parts of an analytical balance. The analytical balance needs and enclosure known as draft shield that helps blocking environmental influences like air currents and dust in the room and will not affect the weighing performance as well as the mass of the sample. One distinguishable feature of analytical balance from a triple beam balance is the digital panel and the tare button. Tare means “to adjust a scale on which an empty container has been placed to reduce the displayed weight to zero” (Merriam-Webster, n.d). Learning Guide 4.5.1 page 2 of 9  Glass Doors/ Draft Shield Weighing Chamber Tare Button Pan Display Panel Figure 4.5.1.3. “Analytical Balance” by Ebultoof is licensed under Public Domain. Here are the essential steps for using an analytical balance. The balance should be placed in a tabletop free from vibrations and should be leveled. Step 1. Plug and turn on the analytical balance. Close all doors and press the “Tare” button. After few seconds, a row of zeros will appear in the display panel (Figure 4.5.1.4) Figure 4.5.1.4. “Taring an Analytical Balance” by Oliver Seely is licensed under CC BY- NC-SA 3.0. Learning Guide 4.5.1 page 3 of 9  Step 2. Open the door and place a weigh paper or small container. Close the door and press Tare button again. Take note to NEVER place the substance to be weighed directly on top of the pan. The container should also be completely dry and at room temperature. Step 3. Add the substance to the weigh paper or a small container by using a small scoop. Be careful not to spill any chemical as it will cause damage to the pan. Always placed the substance to be measured at the center of the weighing pan. Step 4. Close the doors of the balance and wait for a few seconds for the mass reading to stabilize. A. Measuring Mass of Solids You already know the different parts of a triple beam balance but how are we going to use it in measuring mass? A sample triple beam balance reading is shown in Figure 4.5.1.5. How did we come up with this measurement? Figure 4.5.1.3. Triple Beam Balance (Source: Sanders, S.L. (2018). Triple beam balance [Photograph]. Department of Earth Science, College of Arts and Sciences, Northeastern Illinois University. Retrieved from http://homepages.neiu.edu/~llsander/121/Spring17/Balance1.jpg.) Here are the key steps when measuring mass of solids. STEP 1A: Calibrate the balance before using. Empty the pan and slide all three riders to their left most positions. Twist the adjustment knob to make sure the balance pointer is aligned with the fixed zero mark. STEP 2A: Put the object/substance to be weighed on the center of the pan. STEP 3: Slide the 100-gram rider (center beam) to the right one notch at a time. Once the pointer drops below the zero mark, slide the rider back once to the left. STEP 4A: Slide the 10-gram rider (rear beam) to the right one notch at a time. Once the pointer drops below the zero mark, slide the rider back once to the left. STEP 5A: Using a pencil or index finger (pointer finger) slide the 0.1-gram rider (front beam) to the right. Unlike the other beams, no notches are found in the front beam, so keep track of the pointer as you slide. Stop moving the rider when the pointer is in line with the zero mark. STEP 6A: Add the recorded values of the three beams to get the mass of your object. Learning Guide 4.5.1 page 4 of 9  Do not forget to always return the riders to its original position (near the pan) before removing the measured object. In Figure 4.5.1.5, the 100-gram rider is positioned at 200 g, the 10-gram rider is at 10 grams and the 0.1 g is exactly located at 6.1 g. What is the mass of the object? You can practice on how to use and how to get the exact reading of mass measurement using a triple beam balance through this interactive website – Reading a Triple Beam Balance (https://www.wisc-online.com/learn/natural-science/chemistry/gch202/reading-a- triple-beam-balance). B. Measuring Mass of Liquids It is quite easy to measure the mass of solid substances or objects. The mass of solids like rocks, pencil, mug, paper clips etc. can be measured on its own without putting them in a container. However, the mass of a liquid like water cannot be directly measured. Liquids need container. Do you know how to measure the mass of a liquid? Just like measuring the mass of solids, we need to prepare first our triple beam balance. There are only three (3) simple steps to follow. STEP 1B: Measure first the mass of the container. (Follow Steps 1A-6A) STEP 2B: Add the liquid to the container. Measure the mass. STEP 3B: Subtract the mass of the container from the total mass of the container and liquid. The difference is the liquid’s mass. Graded Formative Assessment Now, let us test your understanding of the concepts discussed in this learning guide. Read the direction carefully. Record the measurement of the triple beam balance in each image with correct unit. TA 12 mins A. Measuring Mass of Solids AT 1. Mass of the Object: ________________ Learning Guide 4.5.1 page 5 of 9 2. Mass of the Object: ________________ Learning Guide 4.5.1 page 6 of 9 3. Mass of the Object: ________________ 4. What is the mass of the 250 mL liquid inside a 500 mL beaker? 4.a What is the initial mass of the beaker? Learning Guide 4.5.1 page 7 of 9  4.b What is the total mass of the 250 mL liquid and 500-mL beaker? 4.c What is the mass of the 250 mL liquid? Show your solution. Scoring for item number 4.c 3 points ✓ Correct Solution were shown with units ✓ Final answer is expressed in correct number of significant figures and proper units 2 points ✓ Correct Solution were shown with units ✓ Final answer is not expressed in correct number of significant figures and with proper units 1 point ✓ Correct Solution were shown with no units ✓ Final answer is not expressed in correct number of significant figures and no proper units In Summary Mass is the measure of the amount of matter an object contains. The SI (International System of Units) unit of mass is kilograms (kg). Mass is measured using a balance. TA 2 mins A triple beam balance is a pan balance use to measure mass precisely. AT The analytical balance measure mass accurately and precisely than the triple beam balance. The different parts of a triple beam balance are the pan, three (3) beam and riders, adjustment knob, and the pointer. The steps in measuring the mass of solids are: Learning Guide 4.5.1 page 8 of 9  STEP 1A: Calibrate the balance before using. Empty the pan and slide all three riders to their left most positions. Twist the adjustment knob to make sure the balance pointer is aligned with the fixed zero mark. STEP 2A: Put the object/substance to be weighed on the center of the pan. STEP 3: Slide the 100-gram rider (center beam) to the right one notch at a time. Once the pointer drops below the zero mark, slide the rider back once to the left. STEP 4A: Slide the 10-gram rider (rear beam) to the right one notch at a time. Once the pointer drops below the zero mark, slide the rider back once to the left. STEP 5A: Using a pencil or index finger (pointer finger) slide the 0.1-gram rider (front beam) to the right. Unlike the other beams, no notches are found in the front beam, so keep track of the pointer as you slide. Stop moving the rider when the pointer is in line with the zero mark. STEP 6A: Add the recorded values of the three beams to get the mass of your object. The steps in measuring the mass of liquids are: STEP 1B: Measure first the mass of the container. (Follow Steps 1A-6A) STEP 2B: Add the liquid to the container. Measure the mass. STEP 3B: Subtract the mass of the container from the total mass of the container and liquid. The difference is the liquid’s mass. Albarico, J.M. (2013). THINK Framework. Based on Ramos, E.G. and N. Apolinario. (n.d.) Science LINKS. Quezon City: Rex Bookstore Inc. Bissonnette, C., Herring, F. G., Madura, J. D., & Petrucci, R. H. (2011). General Chemistry: Principles and Modern Applications (10th ed.). Pearson Prentice Hall. Buthelezi, T., Dingrando, L., Hainen, N., Wistrom, C., & Zike, D. (2008). Chemistry: Matter and Change. The McGraw-Hill Companies, Inc. Silberberg, M. S. (2013). Principles of General Chemistry (3rd ed.). McGraw-Hill,. De Camp, U. and Seely, O. (2019, June 06). Proper Use of Balances. Chemistry LibreTexts. https://chem.libretexts.org/Bookshelves/Ancillary_Materials/Demos_Techniques_and_Exp eriments/General_Lab_Techniques/Proper_Use_of_Balances. CC BY-NC-SA 3.0 license. Merriam-Webster. (n.d.). Tare. In Merriam-Webster.com dictionary. https://www.merriam- webster.com/dictionary/tare. Prepared by Reviewed by Reviewed and Approved by PRINCESS GARNET Q. ALBISO CARLITO C. LARIOSA ALICE C. MANUEL Special Science Teacher II Special Science Teacher Special Science Teacher IV Central Visayas Campus Central Mindanao Campus Cagayan Valley Campus Learning Guide 4.5.1 page 9 of 9 © 2020 Philippine Science High School System. All rights reserved. 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