Chemistry Design Lab Kim Li Feb 20th,11 Investigating the effect of different concentration of nitric acid on the its drop volume DESIGN Introduction: Intermolecular forces are forces that hold molecules together. They play important roles in determining the properties of a substance, properties such as boiling point, volatility, viscosity, miscibility, and electrical conductivity. [6] Examples of intermolecular forces include Van der Waals forces, dipole-dipole forces, and hydrogen bonding. Van der Waals forces are temporary dipole all species can form due to uneven distribution of electrons. Dipole-dipole forces are permanent dipoles due to different electronegativity.
2) Mineral chromite contains magnesium, iron, and chromium. Tests will be done to determine if these are in the sample. 3) Magnesium does not absorb nor emit
CHL 161 Laboratory Experiment 4 and 5 Molecular and Electronic Structure Ionic vs. Covalent Compounds and Water Objective: 1. The objective of the Molecular and Electronic Structure Lab was to determine the color of light each solution emits. We also had to identify unknown solutions according the color of light each solution emits. Objective: 2: The objective of the Ionic vs. Covalent Compounds was to determine the physical appearance, solubility and conductivity of compounds. We also have to determine if the compound is ionic or covalent based on our findings.
The second exception to the Octet Rule is when there are too few valence electrons that results in an incomplete Octet. There are even more occasions where the octet rule does not give the most correct depiction of a molecule or ion. This is also the case with incomplete octets. Species with incomplete octets are pretty rare and generally are only found in some beryllium, aluminum, and boron compounds including the boron hydrides. Let's take a look at one such hydride, BH3 (Borane).
that are present in a sample, by generally observing the physical and chemical properties of the sample when they react with compounds with known reagents. After qualitative analysis has positively confirmed the presence of a particular element, ion, or compound, the amount of the substance can then be quantitatively determined through careful measurement (Barezzaghi, 2007). The qualitative detection of particular ions that are dissociated in a solution is dependent on the observed physical and chemical properties that result when the unknown ions react with a specific analyzing reagent with a known outcome. This qualitative method involves testing small samples of the unknown with different unique
Due to their low ionization energy, these metals have low melting points and are highly reactive. The reactivity of this family increases as you move down the table. Alkali metals are noted for how vigorously they react with water. Due to this, they are often stored in mineral oil and are not found in their elemental forms in nature. These characteristics can be explained by examining the electronic structure of each element in this group.
Yuxin Qi IB Chemistry HL II Mr. Balakrishnan Nov. 30th. 2013 Factors Affecting EMF of Electrochemical Cell Aim: To find out one or more factors which affects the EMF of the galvanic cell. Introduction: Galvanic cell is a reaction, producing electricity though redox reactions happening on electrochemical cell. The EMF is a shorten expression of electromotive force which is the voltage. Because of the difference in electronegativity between those town metals, redox reaction happens: Zn(s) → Zn2+(aq) + 2e- Cu2+(aq) + 2e- → Cu(s) In the comparison of voltages produced in this experiment, concentration can be determined whether it is a factor or not.
A circumstance without any of the evidences present concludes that a chemical reaction has not occurred and thus a displacement reaction has not taken place. Figure 1 Figure 1 chlorine + sodium iodide iodine + sodium chloride (non-metal) (compound) (non-metal) (compound) Cl2 + 2 NaI I2 + 2 NaCl Figure 2 Figure 3 Figure 3 (Source of Figure 3: http://vinstan.wikispaces.com/Chapter+3+++++Chemical+Reactions) Purpose: The main objective of Activity Series of Metals is to determine the reactivity of common metals. For this lab we should be able to find out and predict the products that come from a
Mass Spectrometry According to R.William, in order to measure the characteristics of individual molecules, a mass spectrometer converts them to ions so that they can roam about and be manipulated by external electrical and magnetic fields. Since ions are very reactive and short-lived, their formation and manipulation must be conducted in vacuum. Atmospheric pressure must be around 760 torr (mm of mercury). The pressure under which ions may be handled is roughly 10-5 to 10-8 torr (less than a billionth of an atmosphere). In one common procedure, ionization is affected by a high energy beam of electrons and ion separation is achieved by accelerating and focusing the ions in a beam, which is then bent by an external magnetic field.
DISPERSION FORCE / LONDON FORCE The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. This force is sometimes called an induced dipole-induced dipole attraction. London forces are the attractive forces that cause nonpolar substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently. Because of the constant motion of the electrons, an atom or molecule can develop a temporary (instantaneous) dipole when its electrons are distributed unsymmetrically about the nucleus.