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Short essay on atoms
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Lab #4- Molar Relationships
INTRODUCTION
The mole is an important concept in chemistry. This unit is the measure of atoms or particles present in a compound, which is represented by Avogadro’s number, 6.022*1023. Avogadro’s number can be used in conjunction with other measures, like mass, to determine the number of particles in a compound. This allows chemists to learn more about how a compound may react or the behaviors of different chemicals. Another important concept in chemistry in the molar mass of elements and compounds. The molar mass of elements and compounds represents the mass of one mole of that particular particle. For a compound, the molar mass is simply the total of the molar mass of each atom present in the compound. By understanding
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MATERIALS AND PROCEDURE
Materials:
Sealed plastic bags of unknown compounds
Empty plastic bags
Electronic balance
Periodic table
Procedure:
Calculate the molar mass of each of the seven known compounds by adding the molar mass of each element proportionally. Use a periodic table as a guide.
Weigh one empty plastic bag on an electronic balance and record the mass on the data table.
Weigh the sealed plastic bag filled with unknown compound A using the electronic balance and record the mass. Repeat this step for a second trial.
Calculate the average mass of the bag including unknown A for accuracy. Record the data.
Subtract the mass of the empty bag from the average weighed mass of the bag of substance A to find the mass of the substance alone. Record this data on the table.
Divide the mass of unknown A by its respective amount of moles to find its molar mass. Record the data.
Repeat steps 3-6 for unknowns B, C and D.
Compare the unknowns’ molar masses to each known compound’s molar mass in order to determine its identity.
DATA AND OBSERVATIONS
Known Compounds
Compound
Molar Mass
Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.
The Gravimetric Stoichiometry lab was a two-week lab in which we tested one of the fundamental laws of chemistry: the Law of Conservation of Mass. The law states that in chemical reactions, when you start with a set amount of reactant, the product should theoretically have the same mass. This can be hard sometimes because in certain reactions, gases are released and it’s hard to measure the mass of a gas. Some common gases released in chemical reactions include hydrogen, carbon dioxide, oxygen and water vapor. One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout).
Moles Volume HCl Volume Water 2 M 10 cm 3 0 cm 3 1.5 M 7.5 cm 3 2.5 cm 3 1 M 5 cm 3 5 cm 3 0.5 M 2.5 cm 3 7.5 cm 3
This lab was designed so that we, the students, could learn how to determine the molar volume of a gas effectively.
By doing this experiment, I can know the physical and chemical properties of these samples. After I get my results about the physical and chemical properties of these samples, I can compare my results with the information given by the past student and identify the 5 unknown samples, finding out which sample is which substance. Hypothesis = ==
1 mole of a molecular compound contains 6.01 x 1023 molecules. This means that in a reaction in which 2 molecules of one substance react with 1 molecule of another, for instance the formation of water: 2H2 + O2 2H2O, 2 moles of hydrogen molecules will react with 1 mole of oxygen molecules to give 2 moles of water molecules. For an element, the mass of 1 mole is the same as the atomic mass in grams. For a compound, the mass of one mole is the same as the relative formula mass or molecular mass in grams. The molecular or formula mass of a compound is found by adding the relative atomic masses of its constituent elements, as found in the periodic table.
Titrate the solution until the reddish pink color appears. Record the final reading, and calculate the change in volume. Part C. Determination of the molar mass of unknown acid Repeated the procedure above, but this time KHP was replaced with an unknown acidic solution and concentration. Demand the number of replaceable hydrogen from the instructor. Conclusion and Discussion:
First, the mass of the beaker being used was recorded, then about 1g of baking soda was added and the mass recorded. Next, the mass of just the baking soda was found and recorded. Then, the contents were boiled until dry then weighed and mass recorded after cooling off. Finally, the mass of jus the salt, or sodium chloride, was found and recorded.
However I do not know the number of moles for a given mass. I can
Step 5 Mark the bin/refuse bag 1. Step 6 Repeat steps 1-5 at location 2. Step 7 Take your data home and weigh it, then fill your results in a table.
The idea that atoms make up matter has been around for centuries. However, it has only played a role in chemistry for the past 200 years, and the idea hasn’t taken off until the last 100 years.
Chemical background for early atomic structure established that in a chemical reaction, a mass neither forms nor is it destroyed. In explaining this concept, a law of conservation of mass emerged. The law states that any chemical reaction of substances results to creation of new substances, but the total weight of the subsequent products remains same as the total weight of reacted substances. Another law became famous, the law of constant composition, which states that elements in a compound exists in a fixed and equal quantity by mass, irrespective of the source of the compound or preparation method. In today’s world, scientists understand that atoms make up molecules and are the tinniest parts of an element. Atoms consist of electrons, neutrons, and protons. Electrons consist of empty spaces and scientists refer the as elementary. Protons and neutrons...
3. Elements are characterized by the mass of their atoms. All atoms of the same element
Atom is referred to as the smallest and unnoticeable unit of matter. However, ions are atoms in which the number of protons and electrons are not the same. Therefore, ions can either be negatively and positively charged. Atom is made up of neutrons, protons, and electrons. The neutrons and protons make the nucleus of an atom while the electrons surround atom’s nucleus. Atom is electrically neutral because the number of electrons and protons are the same. Neutral Magnesium (Mg) is an atom, and it has 12 electrons and 12 electrons giving it a mass number of 24g/mole. Magnesium easily loses two electrons in its valence shell to be positively charged (cation), the number of protons are greater than the number of electrons in this case. Neutral oxygen (O) with eight electrons and eight protons is an atom. Oxygen atom easily acquire two extra electrons to make it valance shell complete and to become negatively charged; in this case, the number of electrons is more than the number of protons hence it is known anion (Smirnov, 2003). When an atom loses the electrons in their valence shell to become a cation, its atomic radius is always larger than it ionic radius. When an atom attracts electrons to its valence shell to become anion its atomic radius and ionic radius are the same (Housecroft, and Sharpe