Determining the Concentration of a Solution: Beer’s Law Purpose: The purpose of this lab was to measure absorbance value of standard solutions. And to find the relationship between absorbance and concentration. Then determine the concentration and the formula of the unknown CO(NO3)2*nH2O solution. Introduction: The reason we conducted this experiment was to determine the concentration and formula of an unknown solution. We used a calorimeter to monitor the light received by the photocell to determine the absorbance of different concentrations of cobalt chloride hexahydrate.
This is a neutralization reaction between a strong acid and strong base. Therefore the heat of reaction (∆H2) is called as the heat of neutralization of HCl and NaOH solutions. The ∆H2 calculated from this experiment is -6.6944KJ/mol. This is because the enthalpy changes when one mole of H+ ions from an acid (HCl) reacts with one mole of OH- from an alkali (NaOH) to form one mole of water molecules under the stated conditions of the experiment. In the final reaction of the experiment (Part C), solid NaOH will react with an aqueous solution of HCl.
(4 points) q = m × c × Δt Given: q=? m = 34.720g c = 4.18 j/(g x °C) Δt = 41.6°C - 25.2°C = 16.4°C q = (34.720g) (4.18 j/(g x °C) (16.4°C) q = 2380.13j You are trying to figure out the energy change of the water which is the surroundings in the lab. To do that you must take the mass of the metal, which for me was Aluminum, and multiply it by the heat capacity of the water, which was given, then multiply that by the change in temperature, which is the final temperature of the mixture
The more active the metal the more basic it’s saturated hydroxide solution. The sulfate compounds of alkaline earth metals show decreasing solubilites as you go down a group. This characteristic is used as a means of separating and identifying metallic ions in a group. Carbonates are pretty insoluble. You will observe in this experiment some of the characteristics of the alkaline earth metals discussed here and will write balanced equations for all reactions.
How do you go from calculated/measured values to accomplishing stated purpose? (4 pts) The purpose of this lab is to determine the exact concentration of an unknown acetic acid solution. Titrations for two different reactions will be performed. Controlled volumes of one reagent are added to a flask containing the other reagent until the equivalence point of the reaction is reached, one between sodium hydroxide (NaOH) and potassium hydrogen phthalate (KHP) and the other between NaOH and acetic acid (CH3COOH). NaOH (aq) + KHP (aq) —› Na+ (aq) + K + (aq) + P2- (aq) + H2O (l) NaOH (aq) + CH3COOH (aq) —› Na+ (aq) + CH3COO- (aq) + H2O (l) The titration of NaOH with KHP will identify the concentration of the NaOH provided.
Hypothesis: The hypothesis is that the component ions of the solution can be identified. This is because each ion has different solubility conditions. Thus, using their difference in their solubility, the ions can be separated through the method of selective precipitation. After the separation, the ions can be confirmed through other means such as reacting with other substances to see the color change and etc. Materials: Materials Distilled water 0.2 M Silver nitrate (AgNO3) 0.2 M Copper(II) nitrate (Cu(NO3)2) 0.2 M Zinc nitrate (Zn(NO3)2) 0.2 M Iron(III) nitrate (Fe(NO3)3) 0.2 M Manganese(II) nitrate (Mn(NO3)2) 0.2 M Aluminum nitrate (Al(NO3)3) 0.2 M Potassium iodide (KI) 0.2 M Sodium bromide (NaBr) 0.2 M Sodium carbonate (Na2CO3) 0.2 M Sodium chloride (NaCl) 0.2 M Sodium nitrate (NaNO3) 0.2 M Sodium sulfate (Na2SO4) 6 M Sodium hydroxide (NaOH) 6 M Sulfuric acid (H2SO4) 6 M Nitric acid solution (HNO3) 6 M Acetic acid solution (CH3COOH) 6 M Hydrochloric acid (HCl) 6 M Ammonia solution (NH3) 0.1 M Barium chloride (BaCl2) 0.1 M Silver nitrate (AgNO3) 0.1 M Potassium ferrocyanide (K4Fe(CN)6) 0.1 M Potassium permanganate (KMnO4) 0.1 M Potassium thiocyanate (KSCN) Aluminum granules (Al) Saturated barium hydroxide (Ba(OH)2) 0.1% Aluminon 3% Hydrogen peroxide (H2O2) Mineral oil Quantities 25 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 5 mL 8 mL 10 mL 10 mL 10 mL
Introduction The purpose of this lab is to determine the normality of an unknown base using a volumetric titration. The volumetric titration used for this experiment consisted of a standard acid called potassium hydrogen phthalate (KHC8H4O4) titrated with a weak unknown base. An acid-base indicator called phenolphthalein is used in order to view the reaction proceeding to completion. The indicator allows visualization of the acid changing colour when the solution has reached the end point. The normality of the unknown base is calculated after the solution has reached the end point.
Chose and Obtain Sulfate Solution will form aqueous compound as sulfate when combined with anything is aqueous · Is an anion 3. Chose and Obtain Nitrate Is an anion · Need another anion to test and see if order of reactivity is correct for each anion Solution will always form an aqueous compound according to Alchem Table 4. Chose and Obtain Copper Used by different lab partners whose data was observed Carrying Out The Reactions & Collecting Data How Why 5.Place 10ml of water in a test tube Done so aqueous solution may be made 6. Take magnesium nitrate and place 3 drops into test tube with water Done to have one part of the reaction 7. Repeat step 5 and 6 but replace magnesium with zinc Done so 2 metals can be tested at the same time 8.
By recording the amount of silver nitrate (AgNO3) is used, the amount of the chloride used is figured. An indicator is used to help determine when the reaction is complete. The indicator used in this experiment is potassium chromate (K2CrO4). The recorded volume of silver nitrate (AgNO3) used is then used to determine the molarity of the silver chloride (AgCl) created. Moles of AgCl = (Volume of AgNO3 added) × (Molarity of AgNO3) Using the molarity of the silver chloride (AgCl) and the atomic weight of the chloride (35.4527), the weight of the chloride from the original unknown chloride salt sample.
The indicator Phenolphthalein was the substance used to signal when the titration reached the point at which the reactants are stoichiometrically equal as defined by the balance reaction equation. Phenolphthalein is a chemical compound with the formula C₂₀H₁₄O₄ and is often written as "HIn" or "phph" in shorthand notation. Often used in titrations, it turns colorless in acidic solutions and pink in basic solutions. Sodium hydroxide or Hydrochloric acid would not have been as effective or accurate because they would have reacted with the water vapor from the air. In this lab setup, graduated cylinders or beakers were not used.