Pre-Laboratory Assignment for Equivalent Weight of a Metal 1) You are asked to m

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Pre-Laboratory Assignment for Equivalent Weight of a Metal
1) You are asked to make 133 mL of 1.294 M HCl starting with 6.0 M HCl. a) The volume of 6.0 M HCl needed is (to 0.1 mL) ______________ mL
2) You standardize the "1.294 M" HCl by pipetting a known amount of it into a flask and titrating to the phenolphthalein endpoint with an NaOH solution of known concentration Experimental Data: Volume of "1.294 M" HCl used 4.32 mL Concentration of NaOH used 0.1964 M Initial buret reading 0.07 mL Buret Reading at endpoint 27.69 mL Calculate: b) Exact molarity of your HCl ______________ M
3) You weigh an empty gas buret, fill it to the 50.00 mL mark with distilled water and weigh it again. Experimental Data: Mass of empty gas buret 49.05 g Mass of gas buret filled to 50 mL mark with water 103.25 g Temperature of the water 22.4 °C Density of water... @ 20.0 °C 0.9982 g/cc; D35 °C=0.9941 g/cc Specific Gravity of Mercury... 13.55 Calculate: c) Density of water at 22.4 °C (by interpolation) ______________ g/cc d) Volume of water filling buret to 50.00 mL mark ______________ mL e) Extra volume of water in addition to the 50.00 mL ______________ mL
4) You pipet a known amount of this standardized HCl into a 15 cm sample tube and float a "boat" containing your unknown. You hook up the sample tube and contents to the gas buret. You shake the tube to sink the boat and to start the reaction. When the metal unknown is completely dissolved, you read the gas buret and measure the height of the buret's meniscus above the water level. Experimental Data: Volume of standardized HCl used 4.36 mL Weight of metal unknown used 95.1 mg Gas buret reading after reaction is compete 32.61 mL Height of meniscus above water level 10.8 cm Atmospheric pressure 766.6 mmHg Temperature of the water 27.2 °C Calculate (R = 0.0821 L atm/mol K): f) Vapor pressure of water at 27.2 °C interpolate data at... http://genchem.rutgers.edu/vpwater.html ______________ mmHg g) Total volume of gas released ______________ mL h) Partial pressure of hydrogen ______________ mmHg i) Equivalent weight of metal based on amount of hydrogen generated ______________ g/eq
5) The remaining solution in the 15 cm sample tube containing the reaction products and the unused HCl is quantitatively transfered to a flask and titrated to its endpoint with the standard NaOH. Experimental data: Initial volume of buret 0.10 mL Final volume of buret 14.07 mL Calculate: j) Equivalent weight based on the amount of acid used up ______________
Pre-Laboratory Assignment for Equivalent Weight of a Metal
1) You are asked to make 133 mL of 1.294 M HCl starting with 6.0 M HCl. a) The volume of 6.0 M HCl needed is (to 0.1 mL) ______________ mL
2) You standardize the "1.294 M" HCl by pipetting a known amount of it into a flask and titrating to the phenolphthalein endpoint with an NaOH solution of known concentration Experimental Data: Volume of "1.294 M" HCl used 4.32 mL Concentration of NaOH used 0.1964 M Initial buret reading 0.07 mL Buret Reading at endpoint 27.69 mL Calculate: b) Exact molarity of your HCl ______________ M
3) You weigh an empty gas buret, fill it to the 50.00 mL mark with distilled water and weigh it again. Experimental Data: Mass of empty gas buret 49.05 g Mass of gas buret filled to 50 mL mark with water 103.25 g Temperature of the water 22.4 °C Density of water... @ 20.0 °C 0.9982 g/cc; D35 °C=0.9941 g/cc Specific Gravity of Mercury... 13.55 Calculate: c) Density of water at 22.4 °C (by interpolation) ______________ g/cc d) Volume of water filling buret to 50.00 mL mark ______________ mL e) Extra volume of water in addition to the 50.00 mL ______________ mL
4) You pipet a known amount of this standardized HCl into a 15 cm sample tube and float a "boat" containing your unknown. You hook up the sample tube and contents to the gas buret. You shake the tube to sink the boat and to start the reaction. When the metal unknown is completely dissolved, you read the gas buret and measure the height of the buret's meniscus above the water level. Experimental Data: Volume of standardized HCl used 4.36 mL Weight of metal unknown used 95.1 mg Gas buret reading after reaction is compete 32.61 mL Height of meniscus above water level 10.8 cm Atmospheric pressure 766.6 mmHg Temperature of the water 27.2 °C Calculate (R = 0.0821 L atm/mol K): f) Vapor pressure of water at 27.2 °C interpolate data at... http://genchem.rutgers.edu/vpwater.html ______________ mmHg g) Total volume of gas released ______________ mL h) Partial pressure of hydrogen ______________ mmHg i) Equivalent weight of metal based on amount of hydrogen generated ______________ g/eq
5) The remaining solution in the 15 cm sample tube containing the reaction products and the unused HCl is quantitatively transfered to a flask and titrated to its endpoint with the standard NaOH. Experimental data: Initial volume of buret 0.10 mL Final volume of buret 14.07 mL Calculate: j) Equivalent weight based on the amount of acid used up ______________
Pre-Laboratory Assignment for Equivalent Weight of a Metal
1) You are asked to make 133 mL of 1.294 M HCl starting with 6.0 M HCl. a) The volume of 6.0 M HCl needed is (to 0.1 mL) ______________ mL
2) You standardize the "1.294 M" HCl by pipetting a known amount of it into a flask and titrating to the phenolphthalein endpoint with an NaOH solution of known concentration Experimental Data: Volume of "1.294 M" HCl used 4.32 mL Concentration of NaOH used 0.1964 M Initial buret reading 0.07 mL Buret Reading at endpoint 27.69 mL Calculate: b) Exact molarity of your HCl ______________ M
3) You weigh an empty gas buret, fill it to the 50.00 mL mark with distilled water and weigh it again. Experimental Data: Mass of empty gas buret 49.05 g Mass of gas buret filled to 50 mL mark with water 103.25 g Temperature of the water 22.4 °C Density of water... @ 20.0 °C 0.9982 g/cc; D35 °C=0.9941 g/cc Specific Gravity of Mercury... 13.55 Calculate: c) Density of water at 22.4 °C (by interpolation) ______________ g/cc d) Volume of water filling buret to 50.00 mL mark ______________ mL e) Extra volume of water in addition to the 50.00 mL ______________ mL
4) You pipet a known amount of this standardized HCl into a 15 cm sample tube and float a "boat" containing your unknown. You hook up the sample tube and contents to the gas buret. You shake the tube to sink the boat and to start the reaction. When the metal unknown is completely dissolved, you read the gas buret and measure the height of the buret's meniscus above the water level. Experimental Data: Volume of standardized HCl used 4.36 mL Weight of metal unknown used 95.1 mg Gas buret reading after reaction is compete 32.61 mL Height of meniscus above water level 10.8 cm Atmospheric pressure 766.6 mmHg Temperature of the water 27.2 °C Calculate (R = 0.0821 L atm/mol K): f) Vapor pressure of water at 27.2 °C interpolate data at... http://genchem.rutgers.edu/vpwater.html ______________ mmHg g) Total volume of gas released ______________ mL h) Partial pressure of hydrogen ______________ mmHg i) Equivalent weight of metal based on amount of hydrogen generated ______________ g/eq
5) The remaining solution in the 15 cm sample tube containing the reaction products and the unused HCl is quantitatively transfered to a flask and titrated to its endpoint with the standard NaOH. Experimental data: Initial volume of buret 0.10 mL Final volume of buret 14.07 mL Calculate: j) Equivalent weight based on the amount of acid used up ______________

Explanation / Answer

(1) According to law of dilution   MV = M'V'

Where M = Molarity of stock HCl solution = 6.0 M

V = Volume of the stock = ?

M' = Molarity of dilute solution = 1.294 M

V' = Volume of the dilute solution = 133 mL

Plug the values we get , V = (M'V') / M

                                       = (1.294x133)/6.0

                                      = 28.7 mL

So take 28.7 mL of stock 6.0 M HCl solution and make up its solution to 133 mL with water then we get required solution

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