At 50C our results indicated a solubility of 89 g/100mL of H2O which was close to the known solubility of 80 g/100mL. Introduction: When a salt, such as potassium nitrate or sodium chloride, is placed in water a dissolving reaction will occur. At first, the positive and negative ions of the salt compound are only attracted to each other. In order for the salt to dissolve, these bonds must be broken so that the ions disassociate from each other. In the water molecules, hydrogen is slightly positive and oxygen slightly negative so they are attracted to ions of the opposite charge, known as dipole attraction.
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.
The rate law for this reaction is rate = k[acetone]m[H+]n[I2]p where k is the rate constant for the reaction and m, n, and p are the orders of the reaction with respect to acetone, hydrogen ions (acid), and iodine, respectively. Although orders of reaction can be any value, for this lab we will be looking only for integer values for the orders of reaction (0, 1, 2 are acceptable but not 0.5, 1.3, etc.) The rate of the reaction can also be expressed as the change in the concentration of a reactant divided by the time interval: rate = - Δ[ I 2 ] Δt The iodination of acetone is easily investigated because iodine (I2) has a deep yellow/brown color. As the acetone is iodinated and the iodine converted to the iodide anion, this color will disappear, allowing the rate of the reaction to be easily monitored. We can study the rate of this reaction by simply making I2 the limiting reactant in a large excess of acetone and H+ ion.
Background: A reaction rate is the decrease in concentration of a reactant or the increase in concentration of a product with time. Thus, the units for the reaction rate are usually Molarity per second (M/s) – that is , the change in concentration (measured in molarity) divided by a time interval (seconds in this case) (Chemistry: The Central Science, P. 527). Rate is usually calculated by taking an average of the disappearance or appearance of a compound with respect to time. In this case it is calculated by the absorbance of the light. Reaction rate is affected by any catalysts present (which speed up the reaction usually with an intermediate step), temperature (increases the number of particles collisions), concentration (increases the number of collisions), and surface area (increases the space available for collisions).
Sodium Hydroxide + Hydrochloric Acid Sodium Chloride + Water NaOH(aq) + HClaq → NaCl(aq) + H2O(l) Variables Independent The independent variable of the experiment was the amount of sodium hydroxide that we added to the acid. To keep the variable controlled we would measure 1 ml of the sodium hydroxide and pouring that to the hydrochloric acid. Dependent The dependent variables of the experiment were the temperature and the pH number of the mixture. To control the pH and temperature use the electronic probe and data logger. Controlled The controlled variables of the experiment were: A.
Neutralization Osaji Obi 3/28/2013 Introduction The objective of this experiment is to determine the neutralization curves for weak monoprotic and polyprotic acids, and to learn potentiometric pH measurement. Pka is also needed to be determined by the equation of –log(Ka). To find that we use half neutralization and titration with a strong acid. Procedure The solution is diluted to the mark with distilled water. A burette with the standardized NaOH solution is filled.
Then, sodium hydroxide would have to be titrated against the potassium hydrogen phthalate to standardize sodium hydroxide to 0.1M as well. Titration is the procedure used to determine the concentration of some substance by the controlled addition of a solution into a reaction vessel (flask) from a burette. By using titration, the volume of the solution delivered from the burette may be determined very precisely. This reliable primary standard solution became useful as a titration was made against the orange juice to find the molarity of the citric acid. 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.
Calculate the mass of water present in 5.00 ml of the solution. DETERMINATION OF THE EQUILIBRIUM CONSTANT FOR THE HYDROLYSIS OF AN ESTER I. Theory: In order to determine the equilibrium constant for a reaction, it is necessary to know the initial concentrations of the reactants and products and to be able to determine the equilibrium concentration of one of the compounds. Using the stoichiometry of the reaction and the change in concentration of that compound, the changes in concentration and the equilibrium concentrations of all the other reactants and products can be determined. From these equilibrium concentrations, the equilibrium constant for the reaction can be determined.
2Al + Fe2O3 ( Al2O3 + 2Fe (26.98) ( 159.7) (101.96) 124 601 80 b. Al c. 234.3 d. 234 e. 34.1% 1c. A strip of zinc metal with a mass of 2.0g undergoes single displacement reaction with an aqueous solution containing 2.5g of silver(I) nitrate A. Write a balance equation for the above reaction B. Which of the 2 reactants is the limiting reagent? C. Calculate the mass of zinc (II) nitrate formed D. How much excess reagent is left at the end of the reaction?
An Investigation to determine the reaction kinetics of the Iodine-Propanone reaction The Aim for this investigation to use the reaction between Iodine and Propanone, with an acid catalyst, to determine the reaction kinetics of each of the reactants and find out which order each of the reactants is and to develop a rate equation. This will be done by changing the concentrations of the reactants and reacting them in a colorimeter and measuring the colour change over time by measuring the percentage of light absorbed over a constant period of time. Equation- CH3COCH3(aq) + I2(aq) → CH3COCH2I(aq) + H+(aq) + I-(aq) Source- http://www.chemtopics.com/unit09/iodina.pdf This is a substitution reaction because a Hydrogen atom gets substituted for an Iodine atom. The role of the acid catalyst is to speed up the otherwise slow rate of reaction. Nuc: + R-LG → R-Nuc + LG: The electron pair (:) from the nucleophile (Nuc) attacks the substrate (R-LG) forming a new bond, while the leaving group (LG) departs with an electron pair.