Determination of Substance through Density

ratiocination of Substance through immersionD audition 1DENSITY OF SUBSTANCESPrep bed by Paul Okweye and Malinda GilmorePurpose of the ExperimentTo learn about the properties of matter such as parsimony that be practised as a method of physical identification. In this taste the objectives areTo t distributively the correct give of a balance and gradational cylinders,To look on the densities of solids, delicate pellucids and terminations,To determine pctage breaks during experimental analysis, andTo t separately the use of charting of experimental info.Background Information stringency, like boiling augur, color, odor, solubility, and melting headway, is a physical property of matter. Therefore, minginess whitethorn be used in identifying matter. immersion is defined as hole per unit masses and is verbalised mathematically as d = m / v (Equation 1 d is constriction, m is mass, and v is volume). The assiduity of a sample of matter represents the mass containe d within a unit volume of space in the sample. The units of stringency, therefore, are quoted in terms of grams per milliliter (g/ml) or grams per cubic centimeter (g/cm3) for around solid and pellucid samples of matter. The density of a sample represents the mass of the item sample divided by its volume. density (g/ml) = mass (g) volume (ml or cm3) Eqn. 1Often, a density varies with temperature because of the volume of the sample such as gases. Therefore, densities are usually determined and reported at room temperature (about 25oC suffer shelve 1). References such as chemical handbooks always specify the temperature at which a density was measured.As previously stated, density bay window be used as a method of identification. Various things that density give the gate be useful for are listed below send back 1. Densities of various substances at room temperature, 25oC.Density is often used as a point of identification in the mark of an un cognize substance. The density o f the unknow index be used to characterize the unknown from a list of known substances. It is very unlikely for two substances to have the same density, and when added with boiling point and melting point it adds even more validity to the identity of the substance.Density can also be used to determine the submersion of solutions in certain instances. When a substance is dissolved in piss, the density of the solution will be different from that of the pure piddle itself. Handbooks list diminutive information about the densities of solutions as a function of their composition (typically, in terms of percent substance in the solution). If a sample is known to contain just now a single substance, the density of the solution can be measured experimentally, and then the handbook can be consulted to determine what concentration of the substance gives rise to the measured solution density.Several techniques are used for the determination of density of substances. In general, a density determination involves the determination of the mass of the sample divided by the determination of the volume of the sample. However, the method used for find mass or volume depends on whether or not the sample is a solid or a liquid.For solid samples, the volume of the solid can be determined victimization Archimedess principle, which states that an insoluble, nonreactive solid will displace a volume of liquid equal to its own volume. Typically, a solid is added to a liquid in a volumetric container (such as a gradational cylinder) and the change in the liquid level is determined.For liquids, very precise ranks of density may be determined by measuring an accurate volume of liquid in a container that can then be weighed and then determining the mass of the liquid that was measured. A convenient container for determining the volume of a liquid is to weigh a particular volume of liquid in a have cylinder.The density of substances is very important especially when lecture about b uoyancy the tendency or capacity to remain planless in a liquid or rise in channelise or gas. Often one asks the question, Why does methamphetamine hydrochloride float in water supply? The answer to that question depends totally on density of the substances involved. When dealing with water, water can be in the form of ice, liquid or solid (Table 2). The density of ice is 0.917 g/cm3 and then density of water in its liquid state at 25oC (room temperature) is 0.999 g/cm3. Therefore, the density of ice is less than the density of water so that is why ice floats in water.Temperature (oC)Density of peeing (g/cm3)0 (ice)0.917000 (liquid water)0.9998420.9999440.99997100.99970250.997071000.95836Table 2. Temperature Dependence of piddle Density sentry go PrecautionsSafety goggles and lab coat / apron are unavoidable for this labThe solutions used in this lab are flammable. Use them only as directedMaterials and Chemicals have cylinders (25 mL, 50 ml, and 100 mL)Balance reparation square hearIr constant solid state SampleLiquid Sample (Isopropyl alcoholic drink)Distilled wetSodium Chloride (5%, 10%, 15%, 20% and 25% solutions)ProceduresA. Determination of the Density of SolidsObtain a regular shaped solid (cubic alloy). On your data piece of paper, write down the name of the solid and describe its appearance. utilise a balance, weigh the regular shaped solid. Weigh it on a balance to the nearest 0.01 g. immortalize the weight on the data rag in the constituent noticeed weight unit of the Solid.Using a 100-mL calibrated cylinder, add 75 mL of distilled water. magnetic disk the exact volume of water in the gradatory cylinder to the precision permitted by the calibration mark on the cylinder. Record this volume on the data sheet in the naval division designate Initial Volume of Water for the Solid. light place the regular solid (cubic admixture) into the cylinder (do not drop the metal because it could splash the water in the have cylinder). Read the level of the water in the graduated cylinder, again making your determination to the precision permitted by the calibration marks on the cylinder. Record this volume on the data sheet in the discussion arm labelled utmost Volume of Water for the Solid. The change in the water (Vsolid = Vf Vi) level represents the volume of the solid. work out the density of the regular solid (cubic metal) using Equation 1. Record the mensural value (experimental value) of the density on the data sheet in the naval division label observational pass judgment of Density of Solid.Compare the mensural (experimental value) density of the regular solid (cubic metal) with the actual density value provided in Table 3. Record the actual density on the data sheet in the segment labeled literal Density of the Solid.Calculate the percent error of your measurement. Record value on the data sheet in the section labeled Percent Error of Solid.Note Percent Error = observational jimmy Actual Value x 100% Accepted ValueDry the regular solid (cubic metal) with a paper towel and hand over the sample to your instructor.B. Density of Pure Liquids Pure Water (Distilled Water) Clean and prohibitionist out out a 50 ml graduated cylinder. Accurately weigh the dry graduated cylinder using a balance. Record weight on the data sheet in the section labeled Initial system of weights of the Graduated Cylinder (Water).Add 45 mL of water to the graduated cylinder. Record the exact volume of the water in the cylinder, to the level of precision permitted by the calibration marks on the barrel of the cylinder on the data sheet in the section labeled Volume of Water.Weigh the graduated cylinder and water as accurately as possible. Record weight on the data sheet in the section labeled Final weight unit of the Graduated Cylinder (Water).Calculate the density of the water using Equation 1. Record the calculated value (experimental value) of the density on the data sheet in the section labeled Experimental Value of Density of Water.Determine the temperature of the water in the cylinder. You will use the temperature of the water to determine which density value of water to use from Table 2. Record the temperature on the data sheet in the section labeled Temperature of Water.Compare the calculated (experimental value) density of the water with the actual density listed in Table 2. Record the actual density on the data sheet in the section labeled Actual Density of the Water.Calculate the percent error. Record value on the data sheet in the section labeled Percent Error of Water.Clean and dry the graduated cylinder. guide AlcoholObtain a sample of rubbing alcoholic drink (isopropyl alcohol = rubbing alcohol).Clean and dry a 10 ml graduated cylinder. Weigh the dry graduated cylinder as accurately as you can with the balances you have available. Record weight on the data sheet in the section labeled Initial metric weight unit of the Graduated Cylinder (rubbing Alcoho l).Add 5 mL of rubbing alcohol to the graduated cylinder. Record the exact volume of the alcohol in the cylinder, to the level of precision permitted by the calibration marks on the barrel of the cylinder on the data sheet in the section labeled Volume of draw Alcohol.Weigh the graduated cylinder and rubbing alcohol as accurately as possible. Record weight on the data sheet in the section labeled Final Weight of the Graduated Cylinder (Rubbing Alcohol).Calculate the density of the rubbing alcohol using Equation 1. Record the calculated value (experimental value) of the density on the data sheet in the section label Experimental Value of Density of Rubbing Alcohol.Compare the calculated (experimental value) density of the rubbing alcohol with the actual density listed in Table 3. Record the actual density on the data sheet in the section labeled Actual Density of the Rubbing Alcohol.Calculate the percent error. Record value on the data sheet in the section labeled Percent Error of R ubbing Alcohol.Clean and dry the graduated cylinder.C. Density of SolutionsChemical solutions are often described in concentrations and most times in terms of the solutions percent composition on a weight basis. For example, a 1% sodium chloride (NaCl) solution contains 1 g of NaCl in every 100 mL of solution (which corresponds to 1 g of NaCl for every 99 mL of water ( water supply) present).Obtain 50 mL solutions of NaCl in H2O consisting of the following percents by weight 5%, 10%, 15%, 20%, and 25%. Make the weight determinations of NaCl and H2O accurately as possible.Using the method described earlier for samples of pure liquids, determine the mass, volume and density of each of your NaCl solutions. Record that information on the data sheet under the specified section.Compare the calculated (experimental value) density of the NaCl solutions with the actual density listed in Table 3. Calculate the percent errors for each solution. Record value on the data sheet in the section lab eled Percent Error of NaCl Solutions.Using Excel, construct a graph of the calculated (experimental value) density of your NaCl solutions (y-axis) versus the percent of NaCl the solution contains (x-axis). Obtain the straight statement equation (y = mx + b). Record this equation in the designated area on the data sheet.Name_______________________________________________________________________________research laboratory Partner____________________________Section/Day/Time_______________________________Experiment 1DENSITY OF SUBSTANCES entropy SHEETA. Determination of the Density of SolidsSample Name ______________________________Appearance of Solid ______________________________Weight (g) of the Solid ______________________________Initial Volume (mL) of Water for the Solid ______________________________Final Volume (mL) of Water for the Solid ______________________________Volume (mL) of the Solid ______________________________Experimental Value of Density (g/mL) of Solid____________ __________________Actual Density (g/mL) of the Solid ______________________________Percent Error of Solid ______________________________B. Determination of the Density of Pure LiquidsPure Water (Distilled Water)Initial Weight (g) of the Graduated Cylinder (Water) ______________________________ Final Weight (g) of the Graduated Cylinder (Water) ______________________________Weight (g) of Water Sample______________________________Volume (mL) of Water ______________________________ Experimental Value of Density (g/mL) of Water ______________________________ Actual Density (g/mL) of the Water ______________________________ Percent Error of Water ______________________________Name_______________________________________________________________________________Lab Partner____________________________Section/Day/Time_______________________________Experiment 1DENSITY OF SUBSTANCESDATA SHEETRubbing AlcoholInitial Weight (g) of the Graduated Cylinder (Rubbing Alcohol)____________________________ __ Final Weight (g) of the Graduated Cylinder (Rubbing Alcohol) ______________________________Weight (g) of Rubbing Alcohol Sample______________________________Volume (mL) of Rubbing Alcohol ______________________________ Experimental Value of Density (g/mL) of Rubbing Alcohol ______________________________Actual Density (g/mL) of the Rubbing Alcohol ______________________________ Percent Error of Rubbing Alcohol ______________________________C. Determination of the Density of Solutions% NaClMass (g)Volume (mL)Density (g/mL Calculated)Density (g/mL Actual)% error510152025Note Show calculations in your lab report.Name____________________________________________________________________________Lab.Partner____________________________Section/Day/Time_____________________________Experiment 1DENSITY OF SUBSTANCESHOMEWORK SHEET1. Explain density in words.2. What error would be introduced into the determination of the density of the solid if the solid were hollow? Would the density be too hi gh or too low?3. An insoluble, nonreactive metal sphere weighing 18.45 g is added to 21.7 ml of water in a graduated cylinder. The water level rises to 26.8 ml. Calculate the density of the metal.4. An empty graduated cylinder weighs 34.4257 g. A 10-ml pipet sample of an unknown liquid is transferred to the graduated cylinder. The graduated cylinder weighs 40.1825 g when weighed with the liquid in it. Calculate the density of the unknown liquid.5. Your data for the density of the NaCl (sodium chloride) solutions should have produced a straight bank bill when plotted. How could this plot be used to determine the density of any concentration of sodium chloride solution?6. Examine your graph and determine the density for each of the following percents of NaCl 3%, 9%, 15%, 21%, and 45%.