Lab 5 MW

Heat of Neutralization Reaction between a Strong Acid and a Strong Base In calculating the mass of water in the mixture, assume that the volume of the solution is mainly from water and that the volume of HCl and NaOH are negligible. Also, assume that the density of water is 1 g/mL.  volume of HCl solution: 100ml volume of NaOH solution:100 ml total volume of mixture: 200ml mass of water in the mixture:200g initial temperature of water:20°c final temperature of water:23.41°c qwater? qreaction? molarity of HCl solution: molarity of NaOH solution moles of HCl: moles of NaOH: limiting reactant: moles of limiting reactant Δ?reaction:

How to find Moles of magnesium chloride. #7? Freezing-point depression constant (°C/m) Freezing-point of DI water (°C) Magnesium chloride Molar mass (g/mol) Mass of calorimeter (g) Volume of DI water (mL) Mass of magnesium chloride (g) Moles of magnesium chloride (mol) Mass of calorimeter + solution (g) Mass of calorimeter + solution + ice (g) Freezing-point of solution (°C) Mass of calorimeter + ice after decanting (g) Mass of ice added (g) Mass of ice remaining after decanting (g) Mass of melted ice (g) Mass of water in final solution (g) Mass of water in final solution (ko) Solution 1 MgCl2 95.21 17.28 49.0 1.46 0.0153 67.51 113.17 -1.02 43.92 45.66 26.64 19.02 67.79 0.06779 17.46 51.0 Solution 2 MgCl 95.21 2.11 0.0222 70.49 115.77 -1.46 1.86 41.32 45.28 23.86 21.42 72.34 0.07234 0.20 Solution 3 MgCl2 95.21 17.41 49.5 2.98 I

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Using the thermodynamic tables find the enthalpy of reaction for the reaction B2H6 (g) + 6 F2 (g) 2 BF3 (g) + 6 HF (g) --> Select one: a. + 572 kJ b. none of these C. - 3947 kJ d. – 3877 kJ e. - 3912 kJ f. + 3947 kJ g. + 3877 kJ

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B. Calculate how many liters of CO2 are produced 1. For 1.25g sodium bicarbonate 2. For 2.8g sodium bicarbonate 3. For 5.0g sodium bicarbonate

Using the thermodynamic tables find the enthalpy of reaction for the reaction      B2H6 (g)   +   6 F2 (g)    -->    2 BF3 (g)   +    6 HF (g)     a. – 3877 kJ b. – 3912 kJ c. + 3877 kJ d. + 3947 kJ e. – 3947 kJ f. none of these g. + 572 kJ

Write the balanced NET ionic equation for the reaction when aqueous Cs3PO4 and aqueous AgNO3 are mixed in solution to form solid Ag3PO4 and aqueous CSNO3. Be sure to include the proper phases for all species within the reaction.

The concentration of arsenic in an insectide is determined gravimetrically by precipitating MgNH4AsSO4 and isolating Mg2As2O7. Determine the %w/w Arsenic in a 1.500-g sample of insectide if it yields 0.1105g of Mg2As2O7. Solve using gravimetric calculation. Show the complete solution in a paper

Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube turns blue. Select the ions present.   Question 4 options:   Ba2+   Ca2+   Mg2+   NH41+

Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube remains red. Select the ions present.   Question 5 options:   Ba2+   Ca2+   Mg2+   NH41+

In a lab, you diluted a sample of bleach to 1/10 concentration in a 250 vol. flask. Then quantitatively transferred into into a beaker and titrated it with a standard sodium thiosulfate solution with a molarity of 0.1215M. You repeated this 3 times. The data below is the amount of sodium thiosulfate that was titrated in the 3 runs. Calculate the molarity in each run of the diluted bleach and the concentration of undiluted bleach sample.

1. Calcium in a sample solution is determined by atomic absorption spectroscopy (AAS). A stock solution of calcium is prepared by dissolving 1.834 g CaCl, 2H,0 in water and diluting to 1 litre. From this stock solution, the second stock solution is prepared by the dilution factor of 10. Three standard solutions of calcium are prepared from the second stock solution with the following dilution factor: 20 (first standard solution), 10 (second standard solution) and 5 (third standard solution). A blank solution is prepared as well. Absorbance signals of AAS are as follows: 1.5 (blank solution), 10.6 (first standard solution), 20.1 (second standard solution), 38.5 (third standard solution), 29.6 (sample solution). (Molar mass; Ca = 40.00 g mol-, CI = 35.45 g mol-, 0 = 16.00 g mol-', H = 1.00 g mol-1) a. Construct ONE (1) plot that could be used to represent the calibration curve. b. From the plot of Q1a, determine the amount of calcium in parts per million.

Answer question 12&13. Give only the important solutions.

Heat of Reaction, Mole Fraction 1. A group of students perform a series of experiments mixing HCI with an unknown base of the formula M(OH)n. For each trial the total volume of acid and base was 50.0 mL. The concentration of the acid and base solutions were 0.6000 M. The data is plotted in the graph provided. The density of the aqueous solution is assumed to be 1.00 g/mL and the specific heat of water is 4.18 J/g °C in joules 1600 1400 1200 1000 800 600 400 200 0 0.0000 0.6000 M HCI 0 2000 0.6000 M(OH)x 0 4000 0 6000 Mole Fraction of Acid 0 8000 10000 a) What is the limiting reagent at a mole fraction of 0.6 of acid? b) Write a balanced equation for the reaction of M(OH), with HCI. (You must determine "n") c) For one trial, the students measured a temperature change of + 2.9 °C. Calculate q. d) The students calculated a value of q of 1.5 x 10³ J for one of their trials. For this trial 0.015 mol of HCI and 0.015 mol of M(OH), were used. Calculate heat per mole for this reaction.

1. Balance the chemical reaction for combustion of hexane (C6H₁4) with standard air at ratios of 1.0 and 0.7. Determine the mole fractions of O₂, CO₂ and N₂ in a dry sample of the combustion product gas for = 0.7. equivalence

is number 9 correct?

- Calculate the concerntration of NaOH in the solution provided.

b) Determine the standard enthalpy change and std. Gibbs free energy change of reaction at 400 k for the reaction Co(g) +2H2(g) → CH;OH (g) At 298.15 K, AH?.co )= -26.41 kcal/mol, AH?.CH,OH()= -48.08 kcal/mol, AG.co )= -32.8079 kcal/mol, AG.CH,OH(@)= -38.69 kcal/mol, The standard heat capacity of various components is given by. CS = a + bT + cT2 + dT³, where C is in cal/mol-K and T is in K |Component b x10 e x105 d x10° a -0.291 CH3OH CO 4.55 2.186 -1.92 6.726 0.04 0.1283 -0.5307 H2 6.952 -0.0457 0.09563 -0.2079