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# why is the mole important in chemistry

Question:The mole concept is important in chemistry because 1. atoms and molecules are very small and themole concept allows us to count atoms and molecules by weighing macroscopic amounts of material. 2. it establishes a standard for reaction stoi- chiometry. 3. it explains the properties of gases. 4. it provides a universally accepted stan- dard for mass. 5. it allows us to distinguish between ele- ments and compounds.

Question:The mass of the chalk prior to writing is 9.45g. The mass of the chalk after writing is 9.25g. The amount of chalk used to write is 0.2g. The molar mass of chalk (calcium carbonate) is approximately 100.09g/mol. If it is not, then we'll just assume that it is for this situation. (Wiki says it's 100.0869, my calculations say it's 100.09, and other sources say otherwise. So to avoid confusion, it will remain 100.09) 1.I am supposed to find the value of the moles of the used mass of chalk. My answer for this is 20.018 mol, which I got by multiplying the molar mass of chalk (100.09g/mol) by the used mass (0.2g). Is this correct? If not, why? 2.I am supposed to find the number of particles per 1 mole of chalk. My answer for this is 6.0274198 x 10^25 particles per mole, which I got by multiplying the molar mass of chalk (100.09g/mol) by Avogadro's Constant (6.022 x 10^23). Is this correct? If not, why? 3.I am supposed to find the number of particles in the used mass of chalk. My answer for this is 1.20548396 x 10^25, which I got by multiplying the used mass of chalk (0.2g) by Avogadro's Constant (6.022 x 10^23). Is this correct? If not, why? This symbol ^ represents "to the power of". Additional/Non-Important Info: I am in grade 12 and today I have been assaigned a lab report regarding the mole unit of measurement. However, my teacher did not teach anything on the subject. We are supposed to use what we learned in previous years, but we barely covered the mole in grade 10, which was the last time I took a chemistry related course. It is due tomorow. My mark is currently 97 and I can usually figure things out on my own, and i attempted to here, but I have no idea if I am right or not. The internet is not helping and I cant make any connections between this lab and the examples provided by the textbook. This question is the only reason i registered on YA.

Answers:Hello, First off don't get too worried about molar mass as 100.09 is close enough to 100.0869 that the difference is negligible (it shouldn't affect your answer, since you'll be using significant figures). Anyway: ****************** 1. This is incorrect but close! The mistake you made is really common (I still do this and I'm a senior in college). Raising your answer to the -1 will get you the correct answer, as mols is in the denominator. You'll want to use dimensional analysis: 0.2g CaCO3 * 1 mol CaCO3/ 100.09g CaCO3 = whatever the answer is. Remember that you need the all units to cancel except for the unit desired. In this case we're looking for mols. So, as you can see above, the grams will cancel as one is in the numerator and the other in the denominator. Essentially you're multiplying fractions, you just have to remember that the units will cancel as well. This may help: http://www.chem.tamu.edu/class/fyp/mathrev/mr-da.html ****************** 2. Avogadro's number = 6.022x10^23 particles/ 1 mol of anything. So, in 1 mol of H there are just as many particles as in 1 mol of C. So, use dimensional analysis: 1mol CaCO3 * 6.022x10^23 particles/ 1mol CaCO3. Notice moles cancel and we're left with particles. ****************** 3. We used 0.2 g CaCO3. Again, set up dimensional analysis: 0.2g CaCO3 * 1 mol CaCO3/ 100.09g CaCO3 * 6.022x10^23 molecules/ 1 mol CaCO3. Notice that moles and grams cancel and you're left with particles. ****************** I hope this helps! Again, I'll still make common errors when converting units, so don't get too frustrated. Be sure to set everything up as a fraction and you won't make as many errors. When you go off to college you'll get plenty of practice doing this.

Question:dicuss the importance of the mole in the study of chemistry.

Answers:1 mole = 6.02 x 10^23 atoms/molecules/particles/ lava lamps/.... 1 mole of carbon is exactly 12 g of carbon-12 atoms (it's pegged that way). The mass on the periodic table for each element represents, in grams, the mass of one mole of that element. (Those are the three that I can think of...) The importance of the mole really melts down to how small atoms are, and how impossible it is for us to measure out single atoms for any given procedure. Imagine a paper clip. It's basically made of iron. Your run of the mill paper clip weighs about a gram. If you look at the molar mass of iron on the periodic table, it is 55.85 g. In that one little paper clip, we have about 10^22 atoms of iron. It would take us a VERY long time to count them. Grams we can deal with -- we can measure -- but counting that many atoms? No way. We use moles as a counting device -- just like we say, "hey, give me 5 dozen donuts." But the problem is that different atoms have different masses. We use grams to measure out atoms, but ultimately we have to figure out how many of everything there are. That's why we keep going back and forth from moles to grams. When we talk about chemical reactions, we only care about the grams because it tells us how many atoms/molecules/etc. we are. Chemical reactions require us to work with numbers of atoms/ molecules/ etc. (Ex., I need 2 water molecules for this to work). It's like saying that we need a pound of pencils when really, we're more interested in someone giving us three pencils. Fine, the pounds gets us somewhere, but it still doesn't directly tell us how many. We go from mass -> moles so that we can figure out how many. Without moles, the business of figuring out, say, how much product we will make becomes much harder.

Question:besides the mole representing a number, what else is really important about the mole, and what are the 3 parts of the mole? How is it used in calculations? sry i ask so much, i just need help for my finals and i cant understand the books way of explaining this

Answers:Mole is a very fundamental unit in chemistry. As well as physics, mathematics, you need something to estimate, to measure the things you work ( scientist can't say such thing as: put CO2 in an Ca(OH)2 flask and you will get some solid CaCO3, since the result really depends on the mole ration between CO2 and CaCO3) Chemists need to weigh, to measure the volume of things in order to completely understand how they works. If U have the mole + the mass of the substance, you can find it molecular mass and even it formula ( must use more than just calculation). The other way round is to find the mass of a known substance when you have the mole. All chemical equation display the mole ratio of reactants and products. In order to estimate the result, we need to know the mole of one substance ( though in some case that is not required) Many chemical / physical properties are related to moles: volume of a gas, the molarity of a solution, even the pressure of a sealed tank... There is so many important things about mole