Balance Lab Title: Get familiar with a Centigram Balance Purpose: The purpose of this lab was to use the Centigram Balance and the Electronic Balance to measure the weight in grams of a copper slug, a 100ml Beaker, and an unknown substance. The experiment was to help me get familiar with the weighing of certain materials and the different types of weighing, including direct weighing and weighing by difference. Materials: 2 Copper slugs, 2 100ml Glass Beaker, 2 Centigram Balances, 2 Electronic Balances, 2 unknown weights. Method: First, measure the copper slug using the centigram balance, then put the slug inside of a 100ml Beaker and measure its weight and record the value in the table below. Then measure the Beaker by itself and calculate the weight of the slug by difference.
5.51: Which Reagent is limiting and How Much Precipitate is formed? SCH-3UI-03 David Yu Mrs. Hatton Due Date: May 5, 2012 Cut-Off Date: May 12, 2012 Purpose: To experience and use what you have learned in class about gravimetric stoichiometry by predicting and determining the mass of precipitate of two reactants and then comparing what you experience and what you calculated. Background: Avogadro’s constant is 6.02 x 1023 to find the number of entities. A mole is a useable amount of chemicals that is practical to use. The molar mass of a compound or atom is the mass of 1 mole of anything; this is relative to the atomic mass from the periodic table.
Procedure Centigram balance- direct weighing technique 1) Obtain the centigram balance 2) Add the copper slug to the balance 3) Record the mass of the cooper slug in (g) 4) Retain scale and slug for future use. Centigram balance- weighing by difference 1) Obtain the centigram balance 2) Obtain a 100mL beaker. 3) Put the beaker on the scale and record the mass in (g) 4) Transfer the copper slug from the first part of the experiment to the beaker 5) Weight and record the mass of the beaker & slug. 6) Subtract the mass of the beaker from the mass of the beaker & slug. 7) Record the mass of the copper slug in (g) 8) Retain the beaker and slug for future use.
Pre Lab Objective: The purpose of this lab is to obtain the mass and volume of two different metal samples, to graph data, to obtain the slope of graphed data and to display a best fit curve of experimental data in order to graphically determine the density of each metal Background: Understanding the relationship that exists between a substance’s mass and its volume. This relationship is expressed by the physical property called density. (D = M/V). In order to determine the volume of solids, a technique called water displacement is used. A fixed amount of water is added to a graduated cylinder and the volume of water is recorded.
2. Write a complete and accurate procedure for weighing a chemical on the top loading balance. * Turn on the top loading balance by pressing down on the bar, located on the lower front of the balance. * Wait untill the scale zeros out, showing “g” for grams to the far right of the display screen on the balance. * Place a weighing paper on the balance.
Weigh the beaker this will be the weight of the salt record its mass. Calculate the percent mass for salt to water. Observation and Results 1. Mass beaker = 75.000 g 2. Mass beaker + Mixture = 85.175 g 3.
Calculate the concentration of grams of sodium stearate per milliliter of diluted solution. To do this, multiply the concentration of sodium stearate in the dishwashing liquid by the dilution of the solution (1.50 mL dishwashing liquid per 100 mL solution). Answer = 1.5 *10^-4 g/mL 4. Calculate the number of moles of sodium stearate in a single layer. To do this, first take the number of drops used to achieve the monolayer (1 drop) and convert it to mL using the calibrated number of drops per mL.
12. Place a paper towel over the drain, pour the content of the well plate, throw the paper towel and rinse the well plate. DATA, OBSERVATIONS, AND CALCULATIONS: Data Table: Oxidation - Reduction | | Reactions | Mg in Na2SO4 | Bubbles | Zn in MgSO4 | Small bubbles | Pb in Zn(NO3)2 | Dark lead changed into lighter color | Pb in FeCl3 | Changed the lead into slight green yellow | Fe in CuSO4 | Changed the iron into orange color | Note: I added more than 10 drops to make sure that the pieces are well covered. QUESTIONS: A. Based on your observations make an activity series of the metals used.
Introduction: Thyme contains a surprising amount of iron compounds. This experiment enables us to determine the amount of iron(II) present in dried thyme by means of a redox reaction. Method: 1. Weigh accurately about 1g of dried thyme and put into a 250cm3 beaker. Record the mass of thyme used.
Weigh out .15-.16 g of the unknown zinc compound and record exact mass. Transfer it to a dry 125 ml Erlenmeyer flask 13. Conduct a titration and calculate the percent zinc (average of all the trials conducted). V. Post lab questions 1. What is the theoretical percent zinc in a sample of zinc iodide?