Unknown Compounds Lab Report

By identifying the solubility of the unknown, it could lead to a closer interpretation as to what the functional group the unknown may be. Solubility is determined based on intermolecular attractive forces, such as hydrogen bonding, dipole-dipole, and London dispersion forces. Intermolecular attractive forces arise due to different electron environments in different molecules. For example, water molecules are good at dissolving

Solubility – Very soluble (water), Freely soluble (methylene chloride, chloroform, alcohol), Slightly soluble (acetone) and Insoluble (ether).6 Melting point - 120°C or 248°F.5

Solubility is the ability for a solute to dissolve in a solvent which forms a homogeneous solution. For compounds, to be soluble in a solvent, it has to be attracted to the solvent. Which is where intermolecular forces come in. Intermolecular forces are the attractive forces between

The objective of the experiment is to find out which of the known substances were ionic compounds and which were molecular compounds based on their properties. We predict that the compounds with high melting points and conduction of electricity would be ionic compounds because those are the specific properties of an ionic compound. The compounds with low melting points and no conduction of electricity would be covalent compounds because those are the specific properties of a covalent compound. The solubility of the six compounds were checked when each compound was mixed in water and the conductivity of electricity was tested with the electrodes. High and low melting points were tested by putting different substances above a flame and seeing how long it took to melt. It was found that three mystery compounds were ionic compounds while the other three mystery compounds were molecular compounds.

Polar solutes dissolve in polar solvents, and non-polar solutes dissolve in non-polar solvents. Polar solutes dissolve in polar solvents due to the presence of partial charges within the molecules. Electrons are not equally distributed within the electron cloud and therefore one portion of the molecule has a slightly positive charge, and another to have a slightly negative charge. The presence of partial charges within both the solute and solvent allow for the molecules to adhere to one another. For example, water is very polar and its partial charges can dissolve sodium chloride by adhering to the positive sodium ions, and the negative chlorine ions. Polar solutes dissolve in polar solvents because there are no partial charges within either of them. Both substances will mix together because no molecules show significant affinity for the others. The reason the oils and fats did not dissolve in water was because the polar water molecules had no significant partial charges to adhere to in the non-polar solutes. The water molecules therefore were attracted to each other and not the solute and subsequently they were not

As found in the group lab, polar covalent substances are soluble in water due to the dipole-dipole attraction between water and the molecule. They are also soluble in ethyl alcohol for this same reason. Also, they are not conductors in H2O because there are no charged particles floating freely, they are elements, not ions. Lastly, they have a melting point between 1000C and 5000C due to the dipole-dipole forces within the molecule. In the independent lab, it was found that the substance in container 4 met most of the requirements for it to be classified as a polar substance. It was soluble in water and ethyl alcohol, it did not conduct electricity in H2O and had a melting point between 1000C and 5000C. Although, the chemical within this container was not soluble in ethyl alcohol and soluble in hexane. This could have been due to the ratio of the substance and volume of

Salicylic acid, sucrose, paraffin, and sodium stearate are all covalent compounds. The ionic compounds, on average, took much longer to melt than the covalent compounds did. For example, sodium chloride did not melt at all, but paraffin melted, on average, in 28 seconds. The ionic compounds also were more likely to dissolve in the water than the covalent compounds. Sodium carbonate dissolved in the water, but the salicylic acid did not. The ionic compounds also were more likely to conduct energy than the covalent compounds. Sodium bicarbonate conducted some electricity, but sucrose did not. Some exceptions were calcium carbonate, which did not dissolve or conduct electricity, sodium bicarbonate and copper (II) sulfate, which both melted, and copper (II) sulfate which did not conduct

Ionic bonds form by the nature of the atoms themselves. When the atoms chemically combine together, the atoms create a compound that has different properties. The electronegativity between the atoms in the bond determines what type it is. Atoms with higher electronegativity hold atoms more tightly than those with a lower electronegativity. Therefore, when two elements bond, they must fill each others orbitals to create a stable energy electron configuration. Each will have eight electrons in their outer energy. The solubility and bond type lab was to use the compounds solubility to predict the type of bond it contains. To determine so, I added sodium chloride to water in a test tube and some of it dissolved. When the sodium chloride was put

Copper is formed by metallic bonds. This is because it is formed by a strong attraction between the closely packed positive metal ions and because these are surrounded by delocalised electrons to form outer shells. Due to this, we can also deduce that its structure is a Giant Metallic Lattice, meaning that it has a high melting and boiling point, conducts electricity and is insoluble.

Not all materials are created equal in terms of their conductive ability. Some materials are better conductors than others and offer less resistance to the flow of charge. Silver is one of the best conductors, but is never used in wires of household circuits due to its cost. Copper and aluminum are among the least expensive materials with suitable conducting ability to permit their use in wires of household circuits. The conducting ability of a material is often indicated by its resistivity. The resistivity of a material is dependent upon the material's electronic structure and its temperature. For most (but not all) materials, resistivity increases with increasing temperature. The table below lists resistivity values for various materials at temperatures of 20 degrees Celsius.

From their respective structures, we can determine which compounds are polar and which are non-polar. All of the six compounds listed above are polar solutes except for Naphthalene (C10H8). This signifies that all compounds except for naphthalene, which is soluble in water because water is a polar, compound as well. According to the Like-Dissolve-Like theory, if they have the same polarity, then they would dissolve each other. Thus, Sodium chloride, citric acid, sugar, sodium bicarbonate and copper (II) sulfate are soluble in water because both the solute and solvent are polar. Although naphthalene is insoluble in water, it is however soluble in hexane because hexane is a non-polar solvent. Like the other solutes that would dissolve in water because they have the same polarity, naphthalene is soluble in hexane because naphthalene is a non-polar solute and hexane is a non-polar

Water ( ) has a simple molecular structure. It is composed of one oxygen atom and two hydrogen atoms. The water properties are, adhesive forces, cohesive forces, it is a universal solvent, also has a boiling point of 100°C and has a freezing point of 0°C. Adhesive forces are the attractive forces between unlike molecules. Dipole – dipole is a common type of adhesive force. Dipole – dipole forces account for water being attracted to most substances. Dipole – dipole forces are attractions and repulsion between polar moles. These are forces that attract partial positive and negative charge. Dipole – dipole interactions and dipole – ionic interactions accounts for solubility of substances in water. A special type of dipole – dipole interaction is hydrogen bonds. Cohesive forces are intermolecular forces such has those from hydrogen bonding which cause a tendency in liquids to resist separation. Cohesive forces exist between molecules of the same substance. Hydrogen bonds occur when hydrogen is bonded with either a nitrogen, oxygen or fluorine. So in water hydrogen is bonds with oxygen. Hydrogen bonds accounts for water molecules being attracted to each other. Water molecules consist of two hydrogen atoms bonded to an oxygen atom, and its overall structure is bent, form a V shape. This is because the oxygen atom, in addition to forming bonds with the hydrogen atoms, also carries two pairs of unshared electrons. Due to this hydrogen bonds water has a high melting

As mentioned in the discussion, olive oil, vegetable oil, crisco, and lard were soluble in nonpolar solvents and insoluble in polar solvents. This is due to the chemical composition of polar and nonpolar substances which results from the molecular shape as well as properties of dissolving solutes in solution. Polar substances are hydrophilic and contain polar Van Der Waals interactions (intermolecular forces) such as dipole-dipole forces, ion-dipole forces, and hydrogen bonding. Nonpolar substances are hydrophobic and contain non-polar Van Der Waals interactions. ‘Like dissolve like’ is the reason only polar solutes dissolve in polar solvents and why nonpolar solutes dissolve in nonpolar solvents. Molecules with similar polarity have similar intermolecular forces and therefore, can interact with each, or in this case dissolve9. Additionally, the solubility of a compound is determined by the length of the hydrocarbon chain. Long hydrocarbon chains such as the one found in oleic acid makes a compound more insoluble10. Therefore, since the lipids used in this experiment were hydrophobic substances and each lipid has long hydrocarbon chains, the results were consistent with the scientific literature and principles.

Solubility is the property of a chemical substance, in any state, to dissolve within an adequate solvent. Many chemical experiments in the lab will contain a solute in a solvent, therefore important to know the exact reactions that will ensue. Symmetry and polarity play crucial roles in the occurrence of solubility. A primary rule of “like dissolves like”, describes how molecules with the same symmetry are more likely to be soluble with each other. The same rule can be attributed to the tendencies of polar versus nonpolar molecules.

If these metals are put in contact (or otherwise electrically connected), this potential difference yields electron flow amidst them. Corrosion of the less corrosion-resistant metal is usually elevated and attack to the more resistant material is decreased, as compared to the behaviour of these metals when they are not in contact. The less resistant metal becomes anode and the more resistant metal becomes the cathode. Usually the cathodic metal corrodes very less or not at all in this form of couple. Due to the electric currents and dissimilar metals involved, this type of corrosion is called galvanic or two metal corrosion. It is an electrochemical