All matter is made up of atoms. An atom is like a tiny solar system. In the center of the atom is the nucleus which is a cluster of protons and neutrons. The protons have a positive electric charge while the neutrons are electrically neutral. The nucleus makes up almost all of an atom's mass or weight. Whirling at fantastic speeds around the nucleus are smaller and lighter particles called electrons which have a negative electric charge. . The protons have a positive electric charge while the neutrons are electrically neutral. The nucleus makes up almost all of an atom's mass or weight. Whirling at fantastic speeds around the nucleus are smaller and lighter particles called electrons which have a negative electric charge. An atom has the same number of electrons with positive charge and negative charge. An extremely powerful force, called the nuclear force, holds the protons together in the nucleus as they naturally repelled one another electrically. The atoms of each chemical element have a different nucleus. An atom of hydrogen has one proton and no neutrons. An atom of nitrogen has 7 protons and 7 neutrons. Heavy elements have a large number of protons and neutrons. For example, the most common isotope of uranium, uranium-238 has 92 protons and 146 neutrons in its nucleus. Protons are positively charged and so would be deflected on a curving path towards the negative plate. Electrons are negatively charged and so would be deflected on a curving path towards the positive plate. Neutrons don't have a charge, and so would continue on in a straight line. Isotopes are atoms which have the same atomic number but different mass numbers. They have the same number of protons but different numbers of neutrons. The electrons are found at considerable distances from the nucleus in a series of levels called energy levels. Each energy level can only hold a certain number of electrons. Atomic theory, first put in a quantitative conceptual framework by John Dalton, and quantum theory, which emerged in the 1920s as a result of the work of Werner Heisenberg, Erwin Schrödinger, and Max Planck, are the cornerstones of our present-day view on atomic structure. Atomic theory holds that matter consists of vast numbers of small particles called atoms which combine together to form molecules existing in the three main states of matter as gases, liquids or solids. Thomson's experiments led him to propose a "plum-pudding" view of the atom in which a continuous distribution of positive mass extends over the size of the atom with negative "plums" of much smaller mass (i.e. electrons) inserted into it. This model was overthrown by a series of alpha particle scattering experiments carried out by Rutherford, Hans Geiger and Ernest Madden. They were able to observe back-scattering of alpha particles emitted by a piece of radium as they were being shot through a thin gold foil. The fact that alpha particles are positive and that some of them were scattered back could only be explained by proposing that the positive charge and mass in the gold atoms making up the foil could not be continuous and had to be concentrated in a very small region and that the negative region had to be large enough to let some alpha particles through. This led to a view of the atom in which the positive nucleus is central, very dense and significantly smaller than the size of the overall atom. Modern neutron scattering experiments have shown that the radius of a nucleus is proportional to the cubic root of its mass number and that atomic radii, including electron clouds, are about twenty thousand times bigger with a spherical shape or elongated like a football. The view that electrons can be thought of as being arranged in successive shells of increasing energy around the nucleus is called the Bohr model of the atom and one of the most significant contributions of quantum theory has been to show that these energy levels are quantized. This led to the orbital…
values were made and plotted in a thermometer calibration graph as observed temperature vs. correction factor. In subsequent experiments the graph can be used to account for the correction factor of the temperature measured.
2014. Chem 2401 Organic Chemistry I Experiment Manual. P. 1-6.
Cook, N. and McDonald R.S. 2013. Organic Chemistry I&II Techniques Manual for the Organic Laboratory. P 33-37.
The CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, FL.
Garbage to Decompose? Retrieved December 14, 2012, from The Greenest Dollar: http://www.thegreenestdollar.com/2009/05/how-long-our-garbage-lasts/
Lower, S. (2009, September 01). Polymers and Plastics: An Introduction. Retrieved December 10, 2012, from Chem 1 Virtual Textbook: http://www.chem1.com/acad/webtext/states/polymers.html
Moss, L. (2011, September 07). Wasting away: Our garbage by the numbers. Retrieved December 10, 2012, from Mother Nature Network: http://www.mnn.com/lifestyle/responsible-…
Review I: Chemical Compounds, Formulas, and Names
CHEM 1A Dr. Preeti Srinivasan Evergreen Valley College
Formulas Describe Compounds
• A compound is a distinct substance that is composed of atoms of two or more elements. • Describe the compound by describing the number and type of each atom in the simplest unit of the compound.
– molecules or ions
• Each element is represented by its letter symbol. • The number of atoms of each element is written to the right of the element…
titrations in part II and III. Once we determine that, we use it with the sets of titrations with NaOH. Both Marisa and I will equally do work for both parts I, II, and III.
Part I - Acid-Base Titrations with Chemical Indicators
We obtained a 24 chem well-plate, 40 mL of HCl, and 100 mL of NaOH.
We cleaned out a buret with the base, NaOH.
We then obtained three different indicators: Boomcreiol green, Methyl orange, and 1% Phenolphthalein.
Using the well-plate we sorted the indicators into 3…
THE MOLAR VOLUME OF HYDROGEN:
THE REACTION OF MAGNESIUM WITH HYDROCHLORIC ACID
• The molar volume of hydrogen gas will be determined by experimentally measuring the
of hydrogen evolved during the reaction of magnesium with hydrochloric acid.
• The universal gas constant will be measured and class data will be combined for statistical data
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
Laws and concepts…
CHEM 142- Lab Report
Introduction to Measurement
The materials used for this lab was a large beaker and a (250 mL) beaker, Erlenmyer flask (25 mL), pipet, ice, thermometer, ring stand, bunsen burner, and a thermometer clamp.
A beaker (250 mL) was filled completly with ice. Included was just enough water to cover the ice and then a thermometer was placed (2 cm) away from the bottom of the beaker. The temperture was recorded to the nearest .1…
electrolytes. The heat of neutralization for all reactions involving strong electrolytes will be constant and the same amount of heat will be formed (Petrucci et al., 2011).
The experimental procedure used for this experiment was outlined in the CHEM 120L lab manual, experiment #4. All steps were followed without deviation
Part A: Heat of dissolution of NaOH
Mass of calorimeter: 44.90g
Mass of NaOH used: 10.00g
Initial temperature before NaOH added: 23.5°C
Table 1: Temperature of…
February 4, 2015
Precision and Accuracy of Scientific Glassware
The objective of this experiment is to learn which scientific glassware should be used in various circumstances, how to measure volume and mass and how to record laboratory data and observations. Become familiar with significant figures, errors, precision and accuracy associated with the various tools and techniques. To Contain Glassware you will need two Erlenemeyer Flasks, one 125 mL to measure…
Chem 100 Research Project: Essay Outline
Lasers & Medicine
A. Definitions of Lasers and Medicine
1. Laser is a device that emits light through a process of optical amplification
based on the stimulated emission of electromagnetic radiation.
2. Medicine is the applied science or practice of the diagnosis, treatment, and
prevention of disease.
B. How they relate?
1. Cure diseases, surgeries, etc.
WE DID IT
FINAL WAS COMPLETED
Chem Final Review
Intro to chemistry
○ Dimensional analysis (5)
○ Measurements (3)
○ Accuracy and Precision (4)
Matter and energy
○ Matter (2)
○ Nuclear Reactions (41)
○ Fission and Fusion (42)
■ Nuclear bombardment
■ Energy and “missing” Mass
■ Law of Conservation of Mass and Energy
■ Einstein’s Famous Equation (E=mc
■ Nuclear Chain Reactions…