Log in gaiki.amruta 9 years agoPosted 9 years ago. Direct link to gaiki.amruta's post “What is a neutrino? Also,...” What is a neutrino? Also, what are quarks, gluons, mesons and bosons? A detailed explanation, please. • (147 votes) Davin V Jones 9 years agoPosted 9 years ago. Direct link to Davin V Jones's post “Neutrinos are fundamental...” Neutrinos are fundamental particles similar to electrons but without a charge. Electrons and neutrinos are in a class of particles called leptons. Quarks are fundamental particles that are the constituent particles of matter. They combined to form a class of composite particles called hadrons. Hadrons include protons and neutrons, as well as mesons, which are quark-antiquark pairs. Bosons are force carrying particles. They include: photons which mediate the electromagnetic force, gluons which mediate the strong force, W and Z bosons which mediate the weak force, the hypothetical graviton which mediates gravity, and the Higgs boson which mediates the Higgs field. Gluons are the bosons that quarks use to 'stick' together, but they also have the unusual property that they can stick to themselves too. (361 votes) Brittany Melton 9 years agoPosted 9 years ago. Direct link to Brittany Melton's post “At the end of this readin...” At the end of this reading material, when determining the atomic weight of zirconium, why is the answer to the product of (0.0280 x 95.908u) equal 2.68u and not 2.69u? I actually got 2.685424 and rounded up, but in the equation they figured, they did not round up as done normally in math. I'm lost. I actually got 91.24 to this equation. So...can someone please explain the reasons behind not rounding up when appropriate?? • (52 votes) The Chosen One 9 years agoPosted 9 years ago. Direct link to The Chosen One's post “I just want to mention he...” I just want to mention here about significant figures. In science all numbers are rounded using significant figures. A nice video on khan academy teaches how to round in this way https://www.khanacademy.org/math/arithmetic/decimals/significant_figures_tutorial/v/significant-figures (13 votes) JM Soria 9 years agoPosted 9 years ago. Direct link to JM Soria's post “In the 5th paragraph it i...” In the 5th paragraph it is said that "1 u is equal to exactly 1/12 of the mass of a single neutral atom of carbon-12". However if you add: • (26 votes) Ernest Zinck 9 years agoPosted 9 years ago. Direct link to Ernest Zinck's post “The total mass of 6 proto...” The total mass of 6 protons + 6 neutrons is indeed 12.096 u. (50 votes) Clarice Teo 9 years agoPosted 9 years ago. Direct link to Clarice Teo's post “Hey everyone...i just sta...” Hey everyone...i just started learning chemistry (yep i'm a newbie) and i still can't understand the meaning of a charge...could i request a little help please? thankiew:) • (8 votes) Andrew M 9 years agoPosted 9 years ago. Direct link to Andrew M's post “Charge is just a fundamen...” Charge is just a fundamental property of an object or particle, just as mass is. An object's mass tells you how hard a gravitational force will pull on the object. An object's charge tells you how hard an electrical force will pull on the object. There's a lot more about it here (8 votes) gaiki.amruta 9 years agoPosted 9 years ago. Direct link to gaiki.amruta's post “Historically, the units u...” Historically, the units u and amu were defined slightly differently. Can someone please clarify? • (14 votes) Davin V Jones 9 years agoPosted 9 years ago. Direct link to Davin V Jones's post “Atomic mass units used to...” Atomic mass units used to be defined on oxygen and it wasn't consistent in definition between chemistry and physics. It was redefined to Carbon-12 to unify all measurements in physical and chemical sciences and to be consistent. This was officially termed 'unified atomic mass unit' and the symbol set as u. (19 votes) Shreya Addepalli 8 years agoPosted 8 years ago. Direct link to Shreya Addepalli's post “What is a subatomic parti...” What is a subatomic particle? • (5 votes) Matt B 8 years agoPosted 8 years ago. Direct link to Matt B's post “"sub-atomic" literally me...” "sub-atomic" literally means "below the atom." When we discuss subatomic particles, we talk about any particles smaller than the atom. These could be quarks (up/down quarks, which make up protons and neutrons), leptons (neutrinos but also electrons), as well as bosons. These are typically discussed in particle physics and less often in chemistry. (19 votes) Kwadwo Ansah Ofei 8 years agoPosted 8 years ago. Direct link to Kwadwo Ansah Ofei's post “Are there any disadvantag...” Are there any disadvantages of mass spectrometry • (6 votes) Matt B 8 years agoPosted 8 years ago. Direct link to Matt B's post “No "disadvantages" but li...” No "disadvantages" but limitations instead: mass spectrometry will not tell you anything about a structure directly. Also, some types of spectrometry will not allow every molecule to be fragmented in every possible way. (14 votes) Justin Wade a year agoPosted a year ago. Direct link to Justin Wade's post “Oh come on, I got 91.31u ...” Oh come on, I got 91.31u because I didn't round at each step, only at the end? • (1 vote) Richard a year agoPosted a year ago. Direct link to Richard's post “We really shouldn’t be ro...” We really shouldn’t be rounding at intermediate steps, only at the final step. The issue is that when we round too soon it introduces rounding errors which trickle down to the final answer. It is important to keep in mind the amount of significant figures allowed after each operation to know how much you need to round off your final answer. If you do the full calculation without any premature rounding you should get 91.22377 if you do everything correct. Which would round off to 91.22 using proper significant figures. Hope that helps. (17 votes) WaterBarry13 a year agoPosted a year ago. Direct link to WaterBarry13's post “why is it that 0.0280×95....” why is it that 0.0280×95.908u = 2.68u • (7 votes) Richard a year agoPosted a year ago. Direct link to Richard's post “Yeah, you’re right, they ...” Yeah, you’re right, they rounded that last number incorrectly, it should be 2.69 u if they wanted only three sig figs (or two decimal places). In this case whether it is 2.68 or 2.69, the final answer, with sig figs, remains the same. Really though, we shouldn’t be rounding for intermediate answers like the multiplication parts and only round at the very end to limit rounding errors affecting the final answer. Hope that helps. (5 votes) resiko1313 a year agoPosted a year ago. Direct link to resiko1313's post “When bombarding isotopes ...” When bombarding isotopes with electrons, how can we guarantee that all ion have same charge? • (5 votes) Richard a year agoPosted a year ago. Direct link to Richard's post “You need a certain amount...” You need a certain amount of energy to remove electrons from atoms, their ionization energy. So if we limit the bombarding electron’s energy to just the first ionization energy of the target, then we’ll only get +1 ions instead of +2 or +3 ones. Hope that helps. (7 votes)Want to join the conversation?
6 protons times |.007 u + 6 neutrons times 1.009 u= 12.096 (mass of carbon-12)
and then we divide by 12 we get something greater than 1 u.
Should n´t the mass of 1 u be between the mass of the proton and the neutrón 1 p < 1 u <1 n? So that the atomic mass for carbón-12 be exactly 12 u?
But these are isolated protons and neutrons.
Energy is released when you bring them together to form a carbon-12 nucleus.
Energy is equivalent to mass (E =mc²), and the energy released is equal to 0.096 u.
This difference is called the mass defect.
So the mass of a carbon-12 atom is 12.096 u – 0.096 u = 12.000 u
https://www.facebook.com/notes/ask-andrew-high-school-physics/electric-charge-and-field-ib-topic-51/675755755903814
I used my calculator got this: 2.685424
if you round it to the hundredths place
you would get 2.69 [5 is a midway number,
so we should round it off to the higher hundredth]
Please explain what is going on.
thanks
