Experiment 8: Identification of metal ions and inorganic compounds in aqueous solution Introduction: Qualitative analysis is the identification a sample's component(s). Unlike a quantitative analysis, we are not concerned with the amount of a substance present in a sample but only with its identity. In this exercise we will focus on identifying the cations and anions that make up ionic compounds, both solid and in solution. Ideally there would be chemical tests that could be used to identify individual ions without interference by any other ions. Unfortunately, there are often complications. For example, the formation of a yellow precipitate upon addition of aqueous S2- confirms the presence of Cd2+ in a solution. The color of this compound, however, will be hidden if any Pb2+ or Cu2+ are present in solution since they will form a black precipitate with added …show more content…
The most common are precipitation and complexation. In a precipitation reaction, an ion in solution reacts with an added reagent to form a solid. Whether a solid will form from a given reaction can be predicted by the solubility product constant (Ksp) of the solid under the given conditions. Solubility product constants are the equilibrium constants for the dissolution of an "insoluble" ionic solid in water. A low Ksp implies that the compound does not dissolve to an appreciable degree in water. If the two ions are mixed in solution, a precipitate will tend to form. If steps have been taken to remove ions that form competing precipitates, the presence of a properly colored solid can be used to confirm the presence of a given ion. If several different precipitates remain, the conditions of the solution can be manipulated to selectively redissolve one or more of the solids. When the equilibria involved are well understood, selective precipitation can be a powerful tool in the identification of unknown
An error that could have been present during the lab includes not letting the zinc react completely with the chloride ions by removing the penny too early from the solution. For instance, the percent error of this lab was 45.6%, which was determined by the subtraction of the theoretical percent of Cu 2.5% and the experimental percent of Cu 3.64% and dividing by the theoretical percent of Cu 2.5%. This experiment showed how reactants react with one another in a solution to drive a chemical reaction and the products that result from the
It is one of the major inorganic anions. An anion is “a negatively charged ion, as one attracted to the anode in electrolysis.” (dictionary.com). Sodium ions and chloride ions combine to form sodium chloride. While examining the percent of chloride ion is at 40%of the dissolved solids.
Minerals 1. The minerals under the DRI for my age group would be calcium, potassium, sodium, copper ,iron, magnesium, phosphorous, selenium, and zinc. The mineral that comes below the DRI would be be potassium. However, it is not more than 80% below the DRI. However I did have a low potassium intake.
To find chemical equilibrium, the following chemical equation is used in the experiment: Fe3+(aq) + SCN-(aq) FeSCN2+(aq). When iron (III) and thiocyanate react, thiocyanoiron (III) is produced. When the concentration of all ions at equilibrium are known, the equilibrium constant can be calculated by dividing the equilibrium concentration of the reactant by the equilibrium concentration of the products. In this experiment, four equilibrium systems containing different concentrations of three different ion types (Fe(NO3)3, KSCN-, and distilled water) are made and used to determine equilibrium concentrations.
It will be helpful to refer to your chemistry journal notes. Answer questions in complete sentences. Were any of your substances difficult to identify as polar, nonpolar, or ionic? Explain.
These color changes indicate a chemical change, which show that a reaction had occurred. In the first step when o-vanillin and p-toludine, imine was formed. The color change from green to orange suggests that imine appears as orange colored. In the second step, the addition of sodium borohydride reduced the imine into another derivative, which was yellowish lime color. The solution turned clear when acids and anhydrides was added, which indicated the precipitate were dissolved.
+ H2O (g) Reaction 4: when a sulphuric acid is added to the solution that contains copper (II) oxide, a double displacement reaction will occur. the copper (II) oxide will react with the sulphuric acid producing copper (II) sulfate and water. The copper and hydrogen gas replace each other. Balanced Chemical Equation: CuO (s) + H2SO4 (aq) —> CuSO4 (aq) + H2O (l) Reaction 5: when zinc is added to the copper (II) sulfate solution, a single displacement reaction will occur.
Throughout the experiment, copper was altered a total of 5 times, but after the final chemical reaction, solid, elemental copper returned. Each time the solution changed color, a precipitate formed, or when gas appeared, indicated that a chemical reaction was occurring. For the first reaction, copper was added to nitric acid, forming the aqueous copper (II) nitrate (where the copper went), along with liquid water, and
In this assignment you will learn about which ions are responsible for acidity and basicity. You will learn about some of the common properties of acids and bases. You will as well learn about the three main theories defining acids and bases. Last you will learn about the pH scale. The ions that are responsible for making a solution an acid or a base is H+ for responsible for acidic properties and OH- is responsible for base properties.
Electrons in Metals Fallyn Walker 14423422 An electron is a negatively charged, sub atomic particle. It is a fermion, a particle named after the Fermi-Dirac statistics, which describes the electrons behaviour . Bohr proposed that the electron could move from orbitals. This could explain the spectrum for hydrogen but failed for other elements.
Properties of Substances Express Lab 1)The purpose of this lab was to compare the physical properties of different types of solids and how the properties of solids are determined by their intermolecular forces and their intramolecular bonds. Then we were to classify each type of solid as either ionic, metallic, non-polar molecular, polar molecular, or network. Paraffin wax classified as a non-polar molecular, Silicon dioxide was classifies as a network, Sodium chloride was classified as ionic, Sucrose was classified as polar molecular and Tin was classified as metallic. (2)The intermolecular forces that are present in Paraffin wax are dispersion forces, because it is non-polar and carries a negative charge. Followed by Sucrose that has
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, research of definitions of each relating led to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound forms when two or more nonmetal atoms share valence electrons; covalent compounds are also
Nonosmotic Sodium Accumulation and Salt Sensitive hypertension As we discussed earlier, high sodium diet causes water retention and increases the blood pressure by increasing extracellular fluid volume. In contrast to this traditional view, Heer et al. 2000 performed an experiment in which they showed that consumption of high dietary sodium causes a relative shift of fluid from interstitial compartment to intravascular space. They selected 32 healthy male subjects and provided them with a diet rich in sodium (50meq/day to 550meq/day)for 7 days. They observed that total body water present in the subjects didn’t increase.
Through the titration process, we are able to identify physical changes to the mixture such as the colour change to indicate the end point of the experiment. For example, the colour changes of phenolphthalein from colourless to pink and methyl orange from red to orange and subsequently yellow. Acids produce hydrogen ions and bases produce hydroxide ions. This causes the indicator to change colour due to the colour difference from the undissociate molecules.
Dissolving is the process in which a solvent and a solute interact with each other and form a solution. Melting is a physical, or state, change of a solid to a liquid. Based on the provided information if a substance requires a high temperature to melt and dissolves in water, then it is an ionic compound; and if a substance requires a low temperature to melt and does not dissolve in water, then it is a covalent compound. I predict that salt will be an ionic compound, since it is soluble in water, and sugar and wax will be covalent compounds because they