it's a lab

Chemistry is a quantitative science. That is, we are often interested in how much of a reactant we need and how much of a particular product we can expect to produce. In this virtual lab you will see how we can use top-loading electronic balances, with centigram precision. Centigram precision means that they can measure masses to the nearest one hundredth of a Bram, which we can express as 10.01g. All of the masses obtained will be expressed to two decimal places, the nearest 0.019 We never round off data; if the second decimal place is a zero, report it as such. In the process, we will illustrate an important law of nature, the law of conservation of mass. Strictly speaking, weight refers to the force gravity exerts on an object, and since gravity depends on the altitude at which you're working, so does weight. To avoid this variability, we choose to determine the mass, rather than weight. An object's mass is the amount of matter present, which does not change with altitude. At sea level on earth, 10 kilogram of mass (1.0 kg) weighs about 2.2 lb. Someone who weighs 180 pounds on earth, would weigh only 30 lb on the moon, but that 180-1b Individual has a mass of 82 kg. regardless of his or her location . . Procedure 1. Our measurements will involve four items: Two 50-ml beakers, labeled Beaker A and Beaker B. Two different objects with obviously different masses, identified simply as Object 1 and Object 2 2. Determine the mass of each one, 10.01 g. Use the On-Tare (O/T) button to zero the balance before each weighing Beaker A (alone) Beaker B (alone) Object 1 (alone) Object 2 (alone) 3. We now place Object 1 in Beaker A and record the mass. Beaker A+Object 1: Using this mass and the mass of Beaker A alone, we can determine the mass of Object 1. Calculated mass of Object 1 4. Next, we place Object 1 in Beaker B and record the mass again, Beaker B+ Object 1: We use this result and the mass of Beaker 8 alone to determine the mass of Object 1 again. Calculated mass of Object 1 . . . 5. The next step is to repeat the process, but this time using Object 2. Beaker A.Object 2: Beaker B+Object 2 Calculated mass of Object 2 uting Beaker A data (show setup) Calculated mass of Object 2 using Beaker data (show setup 6. Finally, switch to a different balance, weigh Beaker A three times alone, with Object 1, and with Object 2. Beaker A: B Beaker A+Object 1: Beaker A+Object 2: Calculated mass of Object 1 (show setup): Calculated mass of Object 2 (show setup: . . . . Experiment 1: Conservation of Mass Analysis and Conclusions (1) How closely did the mass of Object 1 when weighed alone agree with its mass determined when using Beaker A and Beaker B? Answer the same question regarding the mass of Object 2. (Variations of 0.03 g are considered negligible.) (2) Even though Beakers A and B have different masses, Object I should have the same mass when calculated using Beaker A as it has when calculated using Beaker B. The same should be true for Object 2. Why should this be so? (3) How did the mass of Beaker A on the first balance compare with its mass on the second balance? If there was a difference, suggest an explanation for what you found. (4) Suggest a reason why one should do all mass determinations on the same balance. (5) Some solid objects can be weighed directly, but substances in general should always be weighed in a container. Why? [Hint: the answer is not related to physical state. It applies to solids, liquids, pure substances and compounds.) Chemistry is a quantitative science. That is, we are often interested in how much of a reactant we need and how much of a particular product we can expect to produce. In this virtual lab you will see how we can use top-loading electronic balances, with centigram precision. Centigram precision means that they can measure masses to the nearest one hundredth of a Bram, which we can express as 10.01g. All of the masses obtained will be expressed to two decimal places, the nearest 0.019 We never round off data; if the second decimal place is a zero, report it as such. In the process, we will illustrate an important law of nature, the law of conservation of mass. Strictly speaking, weight refers to the force gravity exerts on an object, and since gravity depends on the altitude at which you're working, so does weight. To avoid this variability, we choose to determine the mass, rather than weight. An object's mass is the amount of matter present, which does not change with altitude. At sea level on earth, 10 kilogram of mass (1.0 kg) weighs about 2.2 lb. Someone who weighs 180 pounds on earth, would weigh only 30 lb on the moon, but that 180-1b Individual has a mass of 82 kg. regardless of his or her location . . Procedure 1. Our measurements will involve four items: Two 50-ml beakers, labeled Beaker A and Beaker B. Two different objects with obviously different masses, identified simply as Object 1 and Object 2 2. Determine the mass of each one, 10.01 g. Use the On-Tare (O/T) button to zero the balance before each weighing Beaker A (alone) Beaker B (alone) Object 1 (alone) Object 2 (alone) 3. We now place Object 1 in Beaker A and record the mass. Beaker A+Object 1: Using this mass and the mass of Beaker A alone, we can determine the mass of Object 1. Calculated mass of Object 1 4. Next, we place Object 1 in Beaker B and record the mass again, Beaker B+ Object 1: We use this result and the mass of Beaker 8 alone to determine the mass of Object 1 again. Calculated mass of Object 1 . . . 5. The next step is to repeat the process, but this time using Object 2. Beaker A.Object 2: Beaker B+Object 2 Calculated mass of Object 2 uting Beaker A data (show setup) Calculated mass of Object 2 using Beaker data (show setup 6. Finally, switch to a different balance, weigh Beaker A three times alone, with Object 1, and with Object 2. Beaker A: B Beaker A+Object 1: Beaker A+Object 2: Calculated mass of Object 1 (show setup): Calculated mass of Object 2 (show setup: . . . . Experiment 1: Conservation of Mass Analysis and Conclusions (1) How closely did the mass of Object 1 when weighed alone agree with its mass determined when using Beaker A and Beaker B? Answer the same question regarding the mass of Object 2. (Variations of 0.03 g are considered negligible.) (2) Even though Beakers A and B have different masses, Object I should have the same mass when calculated using Beaker A as it has when calculated using Beaker B. The same should be true for Object 2. Why should this be so? (3) How did the mass of Beaker A on the first balance compare with its mass on the second balance? If there was a difference, suggest an explanation for what you found. (4) Suggest a reason why one should do all mass determinations on the same balance. (5) Some solid objects can be weighed directly, but substances in general should always be weighed in a container. Why? [Hint: the answer is not related to physical state. It applies to solids, liquids, pure substances and compounds.)