Mass of standard = Initial mass - final mass
= ( 25.6589 +- 0.0002g) - ( 24.7924 +-0.0002g)
= ( 25.6589 - 24.7924) g +- ( 0.0002g + 0.0002g)
= 0.8665 +/- 0.0004 g
A student weighs a sample of a standard by difference. The initial mass is 25.6589 ± 0.0002 g and the final mass is...
The molar mass of sodium carbonate is 105.9888 g/mol. A student weighs out 0.2211 g of it to standardize their HCI solution. The initial reading is 0.23 mL and the final is 41.82 mL. Fill in the missing conversions to determine mols of acid titrated: What is the volume HCI titrated? What is the molarity of the HCI titrated?
A student weighs a sample of potassium hydrogen phthalate (KHP) to prepare a primary standard for a titration. She later discovers that the KHP was contaminated with sugar. To determine the amount of KHP in the mixture, she takes 5.942 g of the mixture and make a 100.0 mL solution. The student then titrates 10.00 mL of this solution with a 0.1491 M sodium hydroxide solution. She finds that 13.12 mL of the NaOH solution is needed to reach the...
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3. A student performs a crystallization on an impure sample of biphenyl. The sample weighs 0.5 g and contains about 5% impurity. Based on his knowledge of solubility, the student de- cides to use benzene as the solvent. After crystallization, the crystals are dried and the final weight is found to be 0.02 g. Assume that all steps in the crystallization are performed cor- rectly, there are no spills, and the student lost very little solid on any glassware...
Initial mass of ice = 150.89 g Final mass of ice = 99.69 g Initial temperature of water = 42 °C Final temperature of water = 0.4 °C Determine the mass of the ice that has melted. Determine the variation of the water temperature (ΔT). a) Calculate the energy (in J) released by 100 g of water when it cooled by ΔT. The specific heat capacity(c) of water is 4.18 J/(g°C). Use the formula Q = mcΔT and the mass...
A student weighs 0.683 g of potassium acid phthalate, HKC_8H_4O_4, abbreviated KHP (MM = 204.2 g/mol) and titrates it with NaoH. The initial buret reading is 0.12 mL and the final buret reading at the end-point is 33.86 mL. a. How many moles of KHP were used? _________ b. How many moles of NaoH were used? ___________ c. What is the molarity of the base? The student then titrates 5.00 mL of vinegar with the same base. The initial buret...
Initial Final Final A student dissolves 8.00 g of NH NO() in 100. g of H2O(l) in a coffee cup calorimeter. Based on the initial and final temperatures of the mixture in degrees Celsius shown in the diagram above the laboratory setup, what is the calculated AT of the water reported to the appropriate number of significant figures? -5.500°C ) -5.50°C © -5.5°C .
A 500.0±0.2-mL solution was prepared by dissolving 25.00±0.03 mL of methanol (CH3OH, density=0.7914±0.0002 g/mL, molecular mass=32.0419±0.0009 g/mol) in chloroform. Find the molarity ± uncertainty of the methanol.
A student weighs out a 3.07 g sample of NiF2, transfers it to a 250. mL volumetric flask, adds enough water to dissolve it and then adds water to the 250. mL tick mark. What is the molarity of nickel(II) fluoride in the resulting solution?
A student weighs out a 14.4 g sample of KBr, transfers it to a 500. mL volumetric flask, adds enough water to dissolve it and then adds water to the 500. mL tick mark. What is the molarity of potassium bromide in the resulting solution? Molarity = M
A student is given a sample of a manganese(II) chloride hydrate. She weighs the sample in a dry, covered crucible and obtains a mass of 24.747 g for the crucible, cover, and sample. Earlier she had found that the crucible and cover weighed 23.599 g. She then heats the crucible to drive off the water of hydration, keeping the crucible at red heat for about 10 minutes with the cover slightly ajar. She then lets the crucible cool, and finds...