In order to find the molar mass of an unknown compound, a research scientist prepared a solution of 0930 g of unknown in 125 g of a solvent the pure solvent had a freezing point. Determination of relative atomic mass refer to cleapss laboratory handbook section 10101 2 if a balance weighing to 0001 g is not available, reasonable results could be obtained by weighing a much longer (eg 30 cm) piece of magnesium ribbon beforehand on a balance weighing to 001 g, measuring its length and then cutting it accurately. A lab team places 0250g of an unknown solid acid in an erlenmeyer flask they neutralize the solid acid with 150ml of 210 m na(oh)(aq) one mole of the acid reacts with one mole of the base calculate the molar mass of the unknown solid acid calculate the molar mass of the unknown acid.
Determination of the equivalent weight of an unknown acid 99 purpose: one mole of hcl is also its molar mass (mm), its equivalent weight and molar mass have the same numerical value in an acid such as h the possible unknown acids in this experiment are given in the table 81. Calculate the molar mass of the unknown substance 71 °c/m x 204 g (solute) x 248 g (solvent) x 224 °c = 2600 g molar mass = 260 g 2 what are colligative properties colligative properties are properties of a solution that change when the condition of the solution changes. Lab 7 - determination of the molar mass of an unknown solid by freezing point depression goal and overview in the first part of the lab, a series of solutions will be made in order to determine the freezing point depression constant, k f , for cyclohexane. In our example, since we have 25 grams of a substance with a molar mass of 56 g/mol, we calculate 25g x (1 / 56g/mol) = approximately 045 moles koh in our solution 4 divide by the liter measurement of the solution to find the molarity.
Determination of the molar mass of an unknown solid by freezing point depression calculate the molar mass of the unknown solid substance a solution containing a known mass of solute per mass of solvent is prepared and its freezing point is measured the number of moles of solute can be determined by rearranging eq. Experiment 15: ideal gas law: molecular weight of a vapor purpose: in this experiment you will use the ideal gas law to calculate the molecular weight of a volatile liquid compound by measuring the mass, volume, temperature, and pressure of the compound in its. Determining the heat capacity of unknown metals heat capacity of an unknown substance by putting it in water and measure the temperature change of the water and the unknown substance in this experiment, this is exactly what was performed lastly, to find the molar mass of the metal, i then divided 25 j/mole k by the heat capacity of. The aim of this experiment is to determine the molar mass and identity of an unknown compound by measuring the depression in freezing point in this experiment, we will first measure the freezing point of pure naphthalene, then.
The objective of this lab is to experimentally determine the molar mass of an unknown and volatile liquid by narendran in types research science molar mass of a volatile liquid lab report for later save related info embed the temperature of the water in the 1 liter beaker was observed through out the experiment. Determining molar mass we can use a measurement of any one of the following properties to determine the molar mass (molecular weight) of an unknown that is the solute in a solution. The number of moles of anything is calculated from the mass of sample and the molar mass the molar mass of fe(nh 4 ) 2 (so 4 ) 2 6h 2 o is 3922 g for sample 1, in which the mas of fas taken was 10092 g, calculate the number of moles of fas present, then click here to check your answer. Part b: determining the molar mass of an unknown acid in this part of the experiment you will use your standardized sodium hydroxide solution to titrate an unknown acid and determine its molecular mass.
Titration of an unknown acid to determine molar mass: the units of molar mass are g/mol this intensive property is the ratio of two extensive properties, as is shown in the figure below. It is likely that the unknown substance is cyclohexane because the average of molar mass from the three trials is 998 g/mol [(945515+89052+115826)/3] and the largest molar mass of the possible substances is 84 g/mol. This experiment is designed to find the identity of an unknown compound by using the phenomenon of freezing-point depression to determine its molecular weight the compound will be dissolved in cyclohexane, and the freezing point of this solution, as well as that of pure cyclohexane, will be measured. To determine the molecular mass of an unknown substance by finding the freezing point of two solutions (bht and para-dichlorobenzene, and bht and the unknown group 1 trial 1 the molecular mass of the unknown substance is 307 g/mol.
Example #2: a hydrate of na 2 co 3 has a mass of 431 g before heating after heating, the mass of the anhydrous compound is found to be 322 g determine the formula of the hydrate and then write out the name of the hydrate. Density is a physical property of a substance and is often used as an aid to its identification density (d) is defined as the ratio of the mass (m) of a substance. 6-1 experiment 6 titration of an unknown acid prepared by stephen e schullery and ross nord, eastern michigan university purpose to determine the apparent molar mass of an unknown monoprotic acid by titrating with a standardized naoh solution. Conclusion: the purpose of this experiment, to become familiar with colligative properties and to use them to determine the molar mass of a substance, was achieved successfully the experiment was not very accurate, but it was still successful in terms of the original purpose.