3 Questions Blog- 3/28/14

1. What tasks have you completed recently?
Recently, I have gone to the 2014 State Spirit Championship with my cheer team and came out with the runner-up trophy in our Co-ed division. I also have completed the NMSBA testing week that is required and I have completed Placement #1 and #2 for chemistry that was due over spring break.

2. What have you learned recently?

These past two weeks have taught me so much about life and how short and beautiful it can be. At the beginning of spring break, my friend was in a really bad car accident and in the end she was okay but you never know how precious time is until you can no longer spend another second with them. This taught me to value everyone and to never leave something unfinished because you never know when something can be taken from you. 
3. What are you planning on doing next?

Next I plan on staying on top of all my classes since it is a brand new semester. I am all rested up from spring break and I am ready to attack all my new obstacles that are thrown my way for the rest of the school year. I will stay organized and study harder in order to try and get all A’s in my classes.

3 Question Blog-3/14/14

1. What tasks have you completed recently?

Recently I have completed a Frankenstein Essay for English about ambition and have watched several movies for AP US History for extra credit. In chemistry, we have recently experimented with moles and empirical formulas as well as molecular formulas. We have also completed a Beans in a Pot Exploratory Lab which we did to help us learn exactly what a mole was representing and how it worked, or how it is used.

2. What have you learned recently? 

In English we have been learning about the Renaissance era and Macbeth; in AP US History we have been learning about pre-war and World War II and the impact it had on our country. In chemistry, I have been learning about the concept of the mole and how to solve molecular and empirical formulas.

3. What are you planning on doing next?

I am planning to further my knowledge on the mole by completing my glog on mole day and I am preparing and planning to try and do my best on the NMSBA testing that is happening all next week.

The mole… In all it’s glory

The most common way to measure chemical substances is through moles . . .Well no, not that kind of mole . . . a chemical mole is a unit of measure, just like a gram or an ounce. It is used internationally so that all chemists speak the same measurement language. The mole was invented because, well, it made sense. Scientists were having a hard time converting between atoms of an element and grams of an element, so scientists came up with a “mole” of substance, which is defined as anything that has 6.02×1023 particles in it.You might recognize 6.02×1023 as Avogadro’s number; this number is used as a constant throughout chemistry, and here we’re going to use it to define the mole. Usually, moles refer to particles that make up a certain amount of an element, and we use moles to measure how much of a substance is reacting in a chemical equation. However, you can also measure other things in moles—for example, a mole of horses would be 6.02×1023 horses . . . which is actually quite a lot. When you think about a mole as 602,000,000,000,000,000,000,000 horses, it seems like way too big of a number to be describing something that fits in a beaker in the chemistry lab! However, because atoms are so small there are bunches of atoms in everything we’re measuring. Therefore, a mole is actually a very appropriate way to measure chemical substances.

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Beans in a Pot~Exploratory Lab

Today in Chemistry we had 5 different types of beans, each in groups of 50, and found the masses of them all. We had the black beans, lima beans, kidney beans, lentil beans and garbanzo beans.  Once we found the masses of each we decide the smallest mass in the lab which was the lentils, we calculated the relative masses. To get relative masses you must take the masses of each sample of beans divided by the mass of the lentils. After we found the relative masses we used our triple beam balances to find out how many beans were in a “pot”, this means how many beans can fit into the relative mass. The pot is a model of a mole because we can now use it to determine the mass or number of beans in any amount or mass of beans. The relative mass used for that of a mole is that of hydrogen, the lightest element. Below are my group’s results that include the bean type, mass of the 50 beans, the relative mass, rank and the number of beans in a “pot”:

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Percent Composition

The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component. To calculate the percent composition of a component in a compound:
1. Find the molar mass of the compound by adding up the masses of each atom I n the compound using the periodic table or a molecular mass calculator.
2. Calculate the mass due to the component in the compound you are for which you are solving by adding up the mass of these atoms.
3. Divide the mass due to the component by the total molar mass of the compound and multiply by 100.
Percent composition=mass due to specific component/ total molar mass of compound *100
For example, find the percent composition of carbon in C6H12O6!
Molar mass of compound: 6(12.01)+12(1.01)+6(16.00)=180 g/mol
Mass due to carbon: 6(12.01)=72.06 g/mol
Percent composition of carbon: 72.06g/mol/180g/mol*100= 40.0%
Percent composition leads to empirical formulas and empirical formulas are the smallest ratio of atoms found in a compound.

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Accuracy and Precision

Accuracy and precision are important concepts, as they relate to any experimental measurement that you would make. Accuracy refers to how closely a measured value agrees with the correct value. Precision refers to how closely individual measurements agree with each other. In any measurement, the number of significant figures is critical. The number of significant figures is the number of digits believed to be correct by the person doing the measuring. It includes one estimated digit. For example, a scale can only mass an object up until a certain decimal place, because no machine is advanced enough to determine an infinite amount of digits. Machines are only able to determine a certain amount of digits precisely. These numbers that are determined precisely are called significant digits. So a scale that could only mass until 99.999 mg, could only measure up to 5 significant digits. In order to have accurate calculations, the end calculation should not have more significant digits than the original set of data. The easiest method to determine significant digits is done by first determining whether or not a number has a decimal point. This rule is known as the Atlantic-Pacific Rule. The rule states that if a decimal point is absent, then the zeroes on the Atlantic/right side are insignificant. If a decimal point is present, then the zeroes on the Pacific/left side are insignificant. The weight of gold, brought up in the “Atomic Weight Changed for 19 Elements” article , is being updated from 196.966 569(4) amu to 196.966 569(5) amu, where the numbers in parentheses represent the uncertainty in the last digit of the atomic weight.

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Hydrate Composition Mini Lab

Today in chemistry we performed a mini lab that involved Copper (II) Sulfate Pentahydrate, a compound that is a deep blue color but turns a white/grey color when heated. We were trying to find the percentage of the hydrate composition and to start this process you must mass everything. This would include the evaporating dish itself, which we got 79.01 g, then we must mass the evap dish with the substance, 81.03 g, and then the mass after the first, second and third heatings, after the first heating we had 80.27 g and after second we had 80.29 g. We did not do a third heating because your two masses after heating should only vary .02 if it differs any more than you have to do the third heating. Once you have all your data, you can be calculating the percentage but you first must find the mass of water. To find the mass of the water you subtract the initial mass from the end mass, in my case our initial mass was 81.03 and our ending mass was 80.27, that would conclude that our mass of water was 0.74 g. To find the overall percentage you would take .74 and divide it by 2.02 (which was the amount of compound we used) then multiply it by 100, and we got 37%. If you used 6.0 g of hydrate that percentage would still be the same because the 37% should be a constant that can be used to show how much of any mass of the hydrate you use is water alone and 6.0 g would leave you with around 2.2 g of water. The results are reliable because I followed the rules of using significant digits and because we didn’t lose any of the hydrate, which would’ve messed up our calculations. For example, if we had blown, shaken or spilled the hydrate out of the the evaporating dish we were boiling the hydrate in, then some of the hydrate would’ve fallen out and now the amount would be lower than what it should’ve been.

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[UPDATE]

CuSO4 * 5H2O        Total mass of hydrate is 249.6 g because Sulfur is 32.07 g, Copper is 63.50 g O4 is 64.00 g, H2O is 18.00 g and you have 5, which means there’s 90.00 g H2O.

Percent Error: Actual-theoretical/theoretical*100 (AT&T)

% error= .74-.728/.728*100=1.65%

Percent composition of Hydrate:

Mass water/Mass hydrate * 100 = Percent composition of hydrate

90.00 g H2O/249.60 g CuSO4*100 = 36.05% H2O