Blog Post 7

Blog Post 7 (Unit 7)

1. Make as many tally marks as you can in 1 minute. How many years would it take you to make a mole of tally marks if you stayed at the same pace without stopping? (Show your work).

4.373772758432x10^15 years

1. What is the molar mass of potassium permanganate? (Show your work).

source: click

K = 39.0983amu
Mn = 54.938
O = 15.999 4(15.999) = 63.996

K+Mn+O4 = 39.0983amu + 54.938amu + 63.996amu = 158.0323 g/mol

1. Calculate the percent composition of each element in silver sulfide. (show your work).

Ag2S
Ag = 107.8682 2(107.8682) = 215.7364amu
S = 32.065amu --> 215.7364amu + 32.065amu = 247.8014 g/mol
Ag% --> 215.7364 g/mol // 247.8014 g/mol = 0.8706 x 100 = 87.0602%
S% --> 32.065 g/mol // 247.8014 g/mol = 0.1294 x 100 = 12.9398%

1. Honors Chemistry: Calculate the empirical formula if a compound is 17.6% Na, 39.7% Cr, and 42.7% O. (Show your work). Regular chemistry: Calculate the percent composition of each element of iron (III) chloride.

Na - 17.6% --> 17.6g/22.99g = 0.7665 -----> 0.7665/0.7636 = 1          2(1) - (multiplied by 2): 2
Cr - 39.7% --> 39.7g/51.99g = 0.7636 -----> 0.7636/0.7636 = 1          2(1) - (multiplied by 2): 2          
O - 42.7% --> 42.7g/15.999g = 2.6689 -----> 2.6689/0.7636 = 3.5          2(3.5) - (multiplied by 2): 7
Compound Imperical Formula = Na2Cr2O7

1. Why did you have to heat the hydrate sample twice in the lab? What evidence would have indicated you inadvertently overheated the hydrate?

By sufficiently heating the sample twice, one could ensure that there was no remaining water left in the sample. As there were two collected points of data from the post-evaporation sample, if there was no change between the first and second heating, it could be determined that there was no remaining water in the sample that could be detected. Overheating results in the production of Copper (II) Oxide, which would affect the amount of water shown to be present. 

1. (This question is worth 30 points, remember to show your work) A student is given a sample of green nickel sulfate hydrate. She weighs the sample in a clean try test tube and obtains a mass of 22.326 g. Earlier she had found that the test tube weighted 21.244 g. She then heats the test tube to drive off the water of hydration. She then lets the test tube to drive off the water of hydration. She lets the test tube cool, and finds it has a lower mass; the test tube and contents then weigh 21.840 g. In the process the sample was converted to yellow anhydrous NiSO4. Fill in the missing parts of the chart:

source: click

a. Mass of Empty Test tube __21.244g___

b. Mass of test tube & NiSO4 * ??? H2O ___22.326g____

c. Mass of test tube and NiSO4 (after last heating) ___21.840g____

d. Mass of NiSO4 ____22.326g - 21.244g = 1.082g <-- with water included 
21.840g - 21.244g = 0.596g <-- without water included____

e. Mass of H2O _____1.082g - 0.596g = 0.486g_______________

f. % NiSO4 in hydrate _mass = 0.596/1.082g * 100 = 55.083%_________________

g. % H2O in hydrate _mass = 0.486g/1.082 * 100 = 44.917%_________________

Molar mass of NiSO4 = 154.8 g       h. Molar mass of H2O _= ([H]1.008amu)*(2) + [O]15.999amu = 18.015g/mol__________________

i. Moles of NiSO4 __154.8g/mol <-- One mol of NiSO4 --> 0.596g/154.8g/mol = 0.0038501 Moles of NiSO4___________________

j. Moles of H2O _18.015g/mol <-- One mol of H2O --> 0.486g/18.015g/mol = 0.0269775 Moles of H2O___

k. Mole ratio of moles of NiSO4 to moles of H20 _0.00385:0.0270 | 0.00385/ --> 0.00385:0.0270 <-- /0.00385 = 1:7 (NiSO4:H2O)_________________________

l. formula of the hydrate  _1 CuSO4 * _7 H2O <-- Found using the ratio. 

Blog Post 6

Blog Post 6 (Unit 6)

Atomic structure of gold particulate taken using an electron microscope.

source

1. Define, compare, and contrast between ionic, metallic, and covalent bonding

Ionic bonding occurs when two ion forms exchange electrons between them, freely. This creates both positively and negatively charged particles as the end result. 

Covalent bonding is the bonded "sharing" or electrons between two atomic particles, where the electrons remain held by both structures.

Metallic bonding occurs between two metals, where electrons are used freely between the separate forms. Charged ionic particles may split off from one, and go towards the other. 

1. Draw a Lewis dot structure and include a picture of your drawing of NCl3

1. What is the molecular geometry of NCl3 and explain using VSEPR theory why that is the shape.

NCl3 is a Trigonal Pyramidal elemental shape. The molecule has four pairs of electrons, meaning the most stable shape, with least resistance for the electron pairs is tetrahedral. Due to the repulsion properties of the differently placed electrons, the lone pair, or unbonded set of electrons is closer to the center of the atomic structure. The non bonded pair of NCl3 is placed on the top of the structure, requiring more room than the other pairs of electrons within the structure. 

source

1. How can the electronegativity of atoms be used to predict the types of bonds in molecules? Help

Electronegativity, the calculated measure of an atomic structure's attraction of electrons. The nearer the atom's valence electron count is to a complete octet (eight electrons present) the greater their electronegativity or electron attraction becomes. The type of predicted bond formed between the two atoms depends upon the difference between the two's electronegativity. If the difference is greater, the bond will become ionic, with one atom removing electrons from the other. If it is a small difference between the atomic structures, the bond will become non-polar covalent, with the electrons sharing between them. If the difference is somewhere between the two, or a moderate distance apart, the bond will be polar covalent; still shared, but drawn towards the increasingly electronegative one. 

source

1. How are empirical and molecular formulas distinguished?

Molecular formulas are direct, exact representations of an atomic model, containing the exact number of atoms within the structure. This is shown often as a ratio-like set of numbers that represent the overall structure of the atom. As a ratio, it can be reduced, and the most highly simplified version of this is named the empirical formula. Empirical formulas and Molecular formulas can both be found using the molar mass shown in the periodic table. 

1. Explain how ionic compounds are named?

Ionic compounds are composed of multiple atomic structures in a way that the overall charge is zero, making them neutral by nature. To begin with, the formula of the compound is written out. To name ionic compounds, the cation or name of the element is named first, followed then by the name of the anion. 

1. What are the rules for naming binary molecular compounds (covalent)?

The binary molecular compounds are named using numerical prefixes depending on how many of each atom are present in the compound. The first of the element uses its element name, as usual, the second uses its root both in combination with the atomic greek prefixes. 

1. How do scientists name acids?

Acids are identified by a cation of Hydrogen. They are named through looking at their molecular suffixes, which determines the type of acid that it is. If the Acid's ending is ide, the name/type of acid becomes hydro___ic acid, likewise, if it ends in ate, it becomes ___ic acid, and the suffix ite is ___ous acid. 

Blog Post 5

Blog Post 5 (Unit 5)

Dmitri Mendeleev 

Source: TFP Mendeleev Biography

1. List two features of Mendeleev’s periodic table that led to its widespread acceptance.

Mendeleev's periodic table included blank spaces where unknown elements that had yet to be discovered were to be placed based upon spaces in his model. Not long after, elements were indeed discovered that fit exactly into the spaces and requirements that Mendeleev had left. 

He predicted the properties of Gallium and Germanium and organized the periodic elements in a table alone. 

1. How do scientists distinguish between metals, Metalloids, and nonmetals?

• Metals are shiny, malleable, ductile, typically in solid form, and are good electrical conductors. 
• Non-Metals are typically gaseous at room temperature, insulators, not malleable or ductile, and have low melting points.
• Metalloids are semiconductors, have properties of both metals, and nonmetals, and form both Covalent and ionic bonds. 

Overall observed differences are Ductile, Malleable, Conductivity, and Luster. Different experiments and tests can be run to test each of these variables and if they are present, while some are simply observed. 

1. Explain the different ways Henry Moseley reorganized the periodic table.

Mosley re-arranged the periodic table in order to solve the problem that Mendeleev came across of not being able to organize ALL elements by their atomic mass. By studying, and measuring the Emission Spectra of elements, Mosley was able to use this light emitted by energized atoms to figure out how many protons were in each atom of each element. This allowed him to create the atomic numbers by which the periodic table is organized today. 

1. Use the periodic table to group these twelve elements into six pairs of elements having similar properties: Ca, K, Ga, Br, Bi, Sn, Cl, Al, Rb, Si, P, Sr.

Element Pairs - similarity-based 

Ca and Sr

K and Rb

Ga and Al

P and Bi

Si and Sn

Cl and Br

1. How do trends in the periodic table predict the properties of an element?

Elements moving across the periodic table from left to right, and then down, increase in atomic mass, therefore getting progressively larger in overall size. On the right side of the step-line, are nonmetals, typically in gaseous form. On the left, are metals, and in the center, lowered portion of the table are transition metals. Moving down the periodic table vertically, the ionization energy of elements, as well as their electron affinity both decrease. Due to the distinct trends in atomic elemental properties, a predicted area of possessed properties for an element can be predicted.                    

1. Describe at least one property common to each of the five main families on the periodic table.

• Group 1: alkali metals. <-- Low melting and boiling points relative to those possessed by other metals. They are also very malleable, and easily cut. 

• Group 2: alkaline earth metals. <-- Somewhat reactive metals with low densities and are typically sliver-white and shiny in appearance. 

• Group 3: halogens. <-- Are reactive non-metals with very high electronegativity levels throughout the group. 

• Group 4: noble gases. <-- Primarily unreactive, and extremely stable elements that contain the greatest number of valence electrons. 

• Group 5: transition metals. <-- Transition metals serve as good conductors of heat, and are also highly malleable/ductile, as well as the ability to form colored compounds. 

1. Explain why Rubidium would have a higher ionization energy than Caesium. 

Caesium has a larger atomic radius, meaning the electrons are more easily lost, the larger the atomic radii become. Because Rubidium has a significantly smaller atomic radius than Caesium, Rubidium possesses a higher ionization energy, making it challenging to remove an electron from it. This is also shown by the two element's placement on the periodic table. Radii increase in size the further down the periodic table a person looks, which correlates with Caesium's placement in relation to Rubidium.

Source: Photographic Periodic Table

1. Explain why transition metals, such as copper and iron, are used as building materials.

Copper and Iron are frequently used as building materials for several reasons. For one, they are both conductive and can be used for wiring and electrics. Copper, being used much more frequently for this purpose is significantly softer than Iron, which is used more often in secure beams, building materials etc. Additionally, both are malleable and ductile and are able to be used easily to mold into whatever shape needed. Abundance is another factor, and as neither are difficult to come across or acquire, they are ideal structural components. 

Transition metals in general, are less reactive than other types of metals and are more easily bent/more malleable. This allows them to be easily formed into different mechanical shapes for building and permits their use in many different functions. 

Source: doityourself - copper vs. aluminum

Blog Post 4

Blog Post 4 (Unit 4)

1. Describe Schrodinger and Heisenberg models of the atom.
Schrodinger proposed that electrons were placed in wrapping waves around the atomic structures.That they were in fact, part of these waves, rather than individual, minuscule particles placed around the nucleus.  

Heisenberg combined the atomic models of Schrodinger and one other atomic scientist. Discovering that the electrons were placed in orbiting rings as Schrodinger thought, but that there were, in fact, small particles within them, that were actually called electrons.  


1. Describe light in terms of frequency, wavelength, and energy. (Include all 7 types of waves).
Light is produced in 7 different types of electromagnetic activity. The first, slowest, lowest frequency and longest wavelength is the radio wave. These are typically used for televisions, and other short distance electronic endeavors. Next, is the microwave. These are slightly smaller, and higher in frequency than the radio waves. These are used for, you guessed it, microwaves, as well as speed cameras. Infrared light has an even smaller wavelength, and are placed immediately next to visible light waves. 


1. What are the photoelectric effect and emission spectra? (It’s the rainbow poster in my room. You may look up this information).
If a light, with a high enough intensity, is shown onto a piece of metal, electrons will be emitted from the metal itself. The energy with which the electron is removed from the substance will depend on the energy of the light. Meaning, the higher the energy within the light is, the electron will be ejected more forcefully. 


1. Write the electron configuration for Antimony.
Atomic number: 51
Number of Protons: 51
Number of Neutrons: 71
Number of Electrons: 51
Electron Configuration: 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4d⁶, 5s², 4d¹⁰, 5p³


1. Write the noble gas configuration for Antimony.





(source) Krypton information myinterestingfacts.com




[Kr] 5s², 4d¹⁰, 4f³ 


1. Draw the orbital diagram (once again, yes draw this one, not find an image on Google).

Antimony (Sb) Block electron diagram drawing.

Antimony (Sb) Orbital diagram drawing.


1. Honors Chem: What are the quantum numbers for antimony? Describe what n, l, m, and s represent.  
n = 5 
l = 1
m = 1
s = +1/2 

n - Represents the energy level placement within the periodic table. 

l - Represents the shape of which the electron creates with its orbital rotation. 

m - represents the order the electrons are placed in with relation to one another within the orbitals. 

s - Represents the either negative, (backward) or positive, (forwards) spin of the electrons. 


1. Describe how you can tell what element this is from the image below and give the correct full electron configuration.



(source) periodictable.com Sulfur information. 




The element shown in the image is Sulfur due to the presence of 4 valence electrons in the picture. Because each arrow represents an electron, there are shown to be 16 electrons in the different, collective, orbitals. This proves it as Sulfur yet again, as it contains 16 electrons. 

Blog Post 3

Blog Post 3 (Unit 3)

1. Describe the history of the atomic model.

To begin with, the atom was seen as a minuscule, indivisible object, typically viewed as being round, and with no internal components. This model was developed by Democritus. After this, it was discovered that atoms possessed negative and positively charged particles within them. This lead to the discovery of protons, and electrons. The nucleus of the atom was eventually concluded to be composed of neutrons and electrons, neutrons being discovered by bombarding the atomic structure with alpha particles. These bounced back, and returned in the direction in which they were launched, proving that there was yet another structure inside the atom. 

1. Explain each subatomic particle including their charge, relative mass, and locations in the atom.

Neutron - Neutrons are neutral, or uncharged subatomic particles occupying the nucleus of the atom. They are the same size as Protons and are 2,000 times larger than the size of an electron.  

Proton - Protons are positively charged subatomic particles placed within the nucleus of the atom alongside the Neutrons. They are the same size of Neutrons and are 2,000 times larger than electrons. The amount of electrical charge possessed by Protons is the same as the amount of electrical charge possessed by Electrons. 

Electron - Electrons negatively charged subatomic particles, located in orbitals around the nucleus of the atom. There are several different orbitals, filled according to how many electrons the atom possessed. Electrons are 2,000 times smaller than 

1. What was Mendeleev’s major contribution to chemistry?

Mendeleev is credited with ordering the elements, in a way nearly accurate to their placement today.  Laying out cards that illustrated the element's properties, and arranging them in such a way that they fit together, is the same method used to organize the periodic table of elements as we see it today. He was the first to try and order them in such a way, and was even able to find spaces, where an undiscovered element would have fit. 

1. Draw and upload a picture of a Bohr model of Gold (yes draw this one, not download a picture).

Electrons: 79

Protons: 79

Neutrons: 118

Energy levels: 6

1. Relate the numbers of the subatomic particles to the atomic number and mass number (use examples).

As one moves through the periodic table, it can be seen that from one element to the next, the atomic mass of the element increases alongside the atomic number of the element. This is what allowed Mendeleev to gain the basis of organization for his periodic table. 

1. Relate the numbers of the subatomic particles to the charge (use examples).

The more protons contained within an atom/isotope, the more positively charged the particle will become. The loss of electrons can also change the charge of the particle, just as the gain of electrons, causes the element to become negatively charged. Noble gasses, have even, and completed outer electron orbitals, resulting in a non-reactive state between them, and even other known elements. The loss, or gain of electrons, changing the charge, and completed status of the valence electron shell, results in the chemical reactions, and chemical bonds seen between elements. 

1. Define atomic mass and use isotopic abundance to calculate. (ex. explain how to find the average mass of Magnesium).

Atomic mass - The average atomic mass of an element is found through the measurement, and averaging of all its isotopic components. Different isotopes are found in different percentages of abundance, thus changing the resulting atomic mass greatly, depending on which is in higher concentration. 

1. Include your calculation for finding the isotope of pennies and identify how many pre-1982 pennies and how many post-1982 pennies were in your unknown container.

x = old pennies

[x(3.1) 10-x(2.5) = 27.26 ] = 2.26 (x = 3.77) 3.77 pennies (4) 

4 Old pennies, and 6 New pennies. Therefore 40% old pennies, and 60% new pennies composed the mixture. 

Blog Post 2

Blog Post 2 (Unit 2)

source: wallpapers-and-backgrounds website: http://wallpapers-and-backgrounds.net/science-wallpaper

1. Draw or describe a particle diagram of an element and compound

Description:  

An element - An element, is a collective substance made up entirely of one type of atom. There are more than 100 different elements, that are the composition of all physical things (that possess a mass) on earth. They are joined by chemical bonds, creating often more complicated forms. 

A compound - A compound, is a collective substance made up of more than one different type of atom. Also referred as a mixture (either homogeneous or heterogeneous). There is a definite ratio of the different atoms, and they are joined by chemical bonds, forming molecules that cannot be separated by physical means. 

1. Draw or describe a homogeneous and heterogeneous mixture.

Description: 

A homogeneous mixture is a blend of multiple different components, that can be combined in a way that the overall mixture has a uniform composition in all respects. 

A heterogeneous mixture is a blend of multiple different components that cannot be combined in a way that the jumble is uniform throughout, and there are obvious separations between the components.  

1. Make a list of 5 physical and 5 chemical properties

Physical: 

• Color
• Volume
• Freezing point
• Temperature
• Mass 

Chemical: 

• toxicity 
• Flammability 
• types of chemical bonds formed 
• The heat of combustion 
• chemical stability 

1. Make a list of 5 physical and 5 chemical changes.

Physical:

• Melting ice cube.
• Chopping wood.
• dissolving another substance into the water. 
• The sublimation of dry ice. 
• Mixing water and oil. 

Chemical:

• Mixing an Acid and a Base.
• Baking a cake.
• Cooking an egg.
• Burning a piece of wood.
• Rusting iron.

1. Describe the 4 states of matter and how energy affects its composition.

Solid - The addition of energy to a solid, causes its componential atoms/particles to move. This, in turn, triggers the solid to switch phases into a liquid due to the increased movement and energy.

Liquid - When more energy is added to a liquid, the particles and atoms increase the speed of their movement until they become airborne and can then be considered a gas.

Gas - Even more energy is added, the gas begins to

Plasma 

1. Describe the 8 different phase changes between the different states of matter.

1. Freezing - The removal of heat from a substance which results in a change from liquid to solid.

2. Melting - The addition of heat to a substance which results in a change from solid to liquid. 

3. Sublimation  - The evaporation, or direct transformation of a substance from solid to gaseous. 

4. Evaporation - The heating of a liquid to the point that it transforms into a gaseous state. 

5. Dissolving - The homogenous combination of two substances, typically solid and liquid to liquid only. 

6. Smoke  - The burning of a solid object until it becomes particularized and gaseous throughout the air. 

7. Condensation - The phase change from gaseous to liquid by the addition of colder temperatures. 

8. Freeze-drying - The freezing, the sublimation of ice particles, so that the substance itself is intact. 

1. Create a pie graph of the %composition of each of the chemicals in the separation of mixture lab. (Either sand, salt, and iron  or  silicon dioxide, sodium chloride, and ammonium chloride).

1. Describe the physical properties used to separate the three chemicals in the lab.

Sublimation, one of the defining properties of the ammonium chloride, was used to initially remove it and measure its absence. The mixture was heated over a hotplate beneath a fume hood, and its gaseous state was evaporated away. Next, water was added to the mixture. This caused the sodium chloride to dissolve into the water, and therefore be evaporated out after being filtered through a coffee filter. Leaving only the silicon dioxide behind. 

Blog Post 1

Blog post 1 (unit 1) 

Japanese Maple Tree, Source: Falcor88 - DeviantArt
https://falcor88.deviantart.com/art/1390614-615874978450917-1162797191-N-413184974 

1. Describe how to find the density of a metal block if the block’s mass is 0.84g, length is 15.55 cm, width is 3.25 cm, and height is 0.00163 cm. (Keep appropriate significant figures

density = mass/volume Volume = length * width * height [Volume = 15.55cm * 3.25cm * 0.00163cm = 0.082]

Density = mass/volume [Density = 0.84g/0.082cm^3 = 10.24]
Density = 10g/cc

1. If you measure 300 cm, how do you convert to meters?

300 centimeters, divided by 100 = 3 meters.

1. List proper safety equipment wardrobe to use during a lab

1. Pants that are long enough to reach below the knee

2. Close toe, and heel shoes

3. safety goggles

4. long hair tied back out of your face
5. Gloves when necessary 
6. Fume hood in lab when working with toxic chemicals 
7. No loose clothing, jewelry etc. 

1. Create a graph for the different thickness of Aluminium foil you measured in the lab. (include proper titles and units and include the accepted value for the thickness).

Graph of Aluminum Foil Measurements 

All units shown are centimeters (The graphing program I used would not allow me to enter units.)

1. What are the rules for zeros for significant figures? (When are they or aren’t they significant?)

Non zero numbers are always significant no matter the placement, any zero placed between two non-zero numbers are counted as significant. Final zeros/trailing zeros following the decimal point are also marked as significant. 

1. Distinguish between accuracy and precision. 

Accuracy: The desired outcome gained, or the state of being correct.

Precision: Every time the result is the same, and repeatable, or the quality of exactness. 

1. What was the % error in your first lab? (Show work)

0.0025 - 0.0024 = 0.0001/0.0024 * 100 = 4.17% error

1. Express the following numbers in scientific notation:

a. 0.000045 = 4.5 × 10-5 

b. 0.023 = 2.3 × 10-2

c. 107,800 = 1.078 × 105

d. 602,000,000,000,000,000,000,000 = 6.02 × 1022