Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Short essay on atoms
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: Short essay on atoms
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 …show more content…
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.
This lab was designed so that we, the students, could learn how to determine the molar volume of a gas effectively.
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.
One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout). It is essentially using the the mass of the product to figure out the original mass that we are looking for. Thus the purpose of our experiment was to compare the final mass in our reaction to the initial mass and determine the change in mass.
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 = ==
However I do not know the number of moles for a given mass. I can
Density is mass of a unit volume of a material substance, expressed as kilograms per cubic meter in MKS or SI units. Density offers a convenient means of obtaining the mass of a body from its volume or vice versa; the mass is equal to the volume multiplied by the density, while the volume is equal to the mass divided by the density. The weight of a body, which is usually of more practical interest than its mass, can be obtained by multiplying the mass by the acceleration of gravity. Tables that list the weight per unit volume of substances are also available; this quantity has various titles, such as weight density, specific weight, or unit weight. D = mass/volume
After the some time, we filter it through a Büchner funnel before it is recrystallized and filtered again. The mass was recorded as it was dry. By adding sodium carbonate, we will now test whether what obtained is benzoic acid or not, because one can observe bobbles if it is an acid. After that we burn it to test if it is aromatic.
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
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...
The Atom An atom is the smallest unit of matter that is recognizable as a chemical ELEMENT. Atoms of different elements may also combine into systems called MOLECULES, which are the smallest units of chemical COMPOUNDS. In all these ordinary processes, atoms may be considered as the ancient Greeks imagined them to be: the ultimate building blocks of matter. When stronger forces are applied to atoms, however, the atoms may break up into smaller parts. Thus atoms are actually composites and not units, and have a complex inner structure of their own.
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.
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
Today, nothing in chemistry would be the same without the idea of the atom. Not only is it the basic building block of all matter, but it is also the basic building block of almost all of our knowledge in chemistry.
of atoms of differing weights and combine in simple ratios by weight, also known as the atomic