Chemistry Definition and 993 Threads

Hello! My name is Fabrizio, I'm a high school student doing some research on the atmosphere. Right now, I'm trying to figure out how much matter escapes into space via Jean's Escape. I've found several formulas, all of which require me to know what the amount of particles per m3 of a certain...

Summary: Thread for discussing the USNCO and how to do well on it. More specifically, tips for doing well on the national round and making the study camp are welcome. Anyone with experience with the olympiad is welcome to post, especially previous study camp qualifiers and honors/high honors...

Hello! There is a problem to write chemical reactions that goes with substances if they are not stored properly. For example theophylline should be saved from light and though I am trying to find its’ reaction with hv(light) but failed. Please help with some good reference Many thanks in advance

I think that the double bond would be broken in some way but what happens to the two bromines? do they remain in the ring? (or does HBr forms? is it possible?)

Summary: Our chemistry teacher gave a sample problem regarding balancing a redox equation. I managed to proceed to a considerable distance, but I can't seem to understand how to get the final balanced equation. Please help me out. The problem is; reaction of K2Cr2O7 with SO2 in the presence of...

Summary: Do chemists think differently than physicists? And should I Change my subject in University... Hey guys, I'm asking myself this question in hoping to find myself in life… some advice and ideas would be really helpful. I'm from Europe and I'm actually studying chemistry. I still Need...

I don't think there is a thread on this? R Gusten et al, Nature, 2019, DOI: 10.1038/s41586-019-1090-x

why do we use the entalphy of formation of water at standard conditions to calculate the entalphy of a reaction even if water is not gas at 1bar and 298K

hii, I'm try to calculate the pressure (in bar) needed for a certain flow rate 3 L/min of Argon gas given the following setup: - I have a tank of Argon gas and the line pressure can be between 0 bar to 5 bar. - The gas will flow out to the open air in the end. - My pipe has an internal radius...

Can someone please tell me what high school chemistry textbook that studying about octet rule is best for an idiot like me?

I’m confused on how to calculate molar solubility because I don’t see what’s the difference between that and Ksp.

I did not opt for physics for my degree course (BSc), I am sort of regretting it. Now, I'd rather want to get close to physics as much as possible. I like physical chemistry, I was thinking I should change my area of interest from neuroscience to physics cause honestly physics is much more...

Does temperature increase when water is boiling at 100C in a closed system? I am picturing a scenario where I am boiling water in a pot to make pasta. However, I decide to close the pot as the water is still boiling. By doing this I am sealing away the system of study from the environment. Thus...

Calculate deltaG for the reaction: H2O(l) = H2O(g). 100 degrees celsius, water is clean. P(H2O) = 0.1 bar. Given that it is an equilibrium, I'd think that deltaG would be zero. But the answer is in fact negative. How is that possible?

Hypothetically, if a chemist/physicist knew all the properties of hydrogen and all the properties of oxygen but knew nothing of water or its properties, would he be able to predict that combining 2 atoms of hydrogen and one atom of oxygen would produce a substance called water and its properties?

Hello everybody, I am stuck with drawing resonance structures for different types of compounds. Do you know any tutorials or any methods to master drawing resonance structures? If yes, please be kind enough to drop some links and statements below. Thank you very much in advance.

Does the understanding and application of physics and fundamental chemistry is only required to be physicist? Or you have to be be equally apt in chemistry??

We all know that the state of matter can be changed by increasing temperature or by applying pressure. And, all of these, in some way lead to a change in the particles' speed. The speed of the particle decides the state of matter. So, if we were to throw an object at very high speeds, like 50%...

Why do we have to memorize the structures of all the nitrogen oxides? Isn't there any way to understand about the Lewis structures of all the nitrogen oxides and their weird ways of making bonds?

Homework Statement In an organic compound "A" only C,H and O is present. 1.22g of A is completely burned and it gives 0.84g of CO2 and 0.54g of H2O. If the relative molecular mass of "A" is 123. Find the molecular formula of A. [/B] I have showed my attempt at solving this problem, but I think...

My chemistry teacher gave me this problem. I tried and tried, but I couldn't figure it out and the deadline is tomorrow. Please help me out here friends. 1. This is the problem : In a compound which is made of element Y, weight percentage of Y is 72% and N( Nitrogen) is 28%. Also, 3 Y atoms...

We are learning the lesson about gases/gaseous states at our school and I couldn't help but wonder, why learn about IDEAL GASES... How do ideal gases help us to analyze about real gases?

Homework Statement Homework EquationsThe Attempt at a Solution I don’t have a clue on how to do the calculations. I know the equivalency point is at the steepest part of the derivative graph. Please don’t say just figure it out, I truly need help. I haven’t learned titrations in lecture yet...

Homework Statement Solid sodium bicarbonate decompose when it's heated above 50 celsius. However, when it is dissolved in water interactions of components changes. So what happens when sodium hydrogen carbonate solution is heated? Does it release carbon dioxide when temperature is above 50...

Hello, I am a bit confused re. solubility calculations. Calculate the solubility of Pb(OH)2 at pH 10. Setting up the expression for Ksp: Ksp = [Pb2+][OH-]2 = 8* 10^-17 (Ksp value from SI chemical data) pOH = 14 - 10 = 4, i.e. [OH-] = 10-4. 8*10-17 = [Pb2+][OH-]2. Solving for [Pb2+] we get...

Hello Being a professional physicist(Quantum field theory and HS theory) I'd like to learn chemistry for some reasons. I've already tried to find a nice Chemistry textbook but failed to find physicist friendly one. My last class on chemistry was in high school like 11 years ago already, so my...

Published this week in the journal Science, researchers report that they have devised a eight letter alphabet for DNA and RNA: The work builds off of previous work, which had expanded the genetic alphabet to six letters. The researchers call their eight-lettered nucleic acids "hachimoji,"...

Homework Statement calculate the number of moles of potassium manganate required to neutralise oxalic acid. 2KMn)4- + 5H2C2O42-+ 16H+ --> 2Mn2+ + 10CO2 + H2O Homework Equations n = c x V n= m/Ar The Attempt at a Solution Moles of oxalic acid = 5x10-4 Volumeol of KMnO4 = 0.01085dm-3...

Homework Statement Kc = 4.15 x 10-2 at 356°C for PCl5(g) ↔ PCl3(g) + Cl2(g). A closed 2.00 L vessel initially contians 0.100 mol PCl5. Calculate the total pressure in the vessel (in atm to 2 decimal places) at 356°C when equilibrium is achieved. Homework Equations PV=nRT Kp= Kc(RT)^change in...

Homework Statement Kc = 1.37 for HI(g) ↔ 1/2 H2(g) + 1/2 I2(g). What is Kc (to 3 decimal places) for H2(g) + I2(g) ↔ 2HI(g)? Homework Equations Kc= Products/Reactants, Ice Tables The Attempt at a Solution I tried an ice table, but I’m not sure what to do with the Kc value I’m given when I...

Homework Statement NaCl has a density of 2.16 g/cm3 and a surface energy of 2x10-5 J/cm2. Calculate the surface energy of 1 g of NaCl. Initially the complete 1 g is in the form of a single cube (of mass 1 g) and progressively broken into smaller cubes with sides of 0.1 cm, 0.01 cm, 10 μm, 1 μm...

Homework Statement Aluminum metal dissolves in hydrochloric acid. What volume, in mL, of 1.58 M HCl is needed to completely dissolve 3.200 g of aluminum?(Hint: write the single-replacement reaction first) Homework Equations V[1]M[1]=V[2]M[2] The Attempt at a Solution I got the...

The enthalpy of formation equation: ΔHƒ°reaction=∑Δhƒ°(products)-ΣΔHƒ°(reactants) When using the enthalpy of formation equation you get: -2010-((-394x3)+(-286x4))= 316Kjmol-1 However, this answer is wrong. On the mark scheme, the answer is -316Kjmol-1. So I used the enthalpy of combustion...

Homework Statement Homework Equations Formula of Kp and Kc The Attempt at a Solution You will easily be able to identify that the reaction will proceed in the forward direction when some inert gas is introduced. So,my question is that why won't the amount of chlorine formed increase in...

Hello, I'd like to work in the above named center at the University of Georgia in Athens, Georgia under Dr. Henry Schafer. However, he's a professor in the chemistry department. I'm guessing if I go in the university as a physics graduate student I can't have him as a Ph.D advisor. However, is...

What does it mean and why do acetophenone and acetic acid have it in their name ?

I'm a weak student in chemistry, by 'weak' I mean I lack some base I think. May please suggest some good books on inorganic chemistry? I want to study p-block, d- and f-block elements along with their important compounds and their preparation. Book should be concise as for me as a weak student...

I’ve already taken intro chemistry with a lab, and general chemistry 1. Unlike most universities, my college doesn’t require chemistry for physics majors. Should I take general chemistry 2? Would it really benefit me, or should I spend my time elsewhere? Edit: I’m referring to the standard...

Homework Statement Hello, As part of my engineering orientation class, my team and I have to make a device that can keep a beaker of water warm. We have a list of materials we can and cannot use, but my team and I have decided on aluminum foil and maybe wood. We don't actually have to build...

Homework Statement The relationship between pH and pOH, for pure water, at 25 ◦C is 14 = pH + pOH What is the corresponding relationship between pH and pOH, for pure water, at 70 ◦C? Homework Equations Le Châtelier's principle? [H+][OH-] = 10-14 [10-7][10-7] = 10-14 (25 ◦C) [10-n][10-m] =...

Homework Statement Which one is more reactive, CO2 or NO2? Homework Equations The Attempt at a Solution I drew the Lewis structures of these species and found there is one delocalized electron in NO2, so I think NO2 is more reactive. Am I correct?

Homework Statement The question's in the screenshot attached. Homework EquationsThe Attempt at a Solution I don't know why (B) would be right. I feel like since for Mg's second ionisation energy, it is going from Na to Ne, and Ne is another energy level, Mg's 2nd ionisation energy should be...

Homework Statement There are four things to be calculated: -pH of 0.00196M solution of HCl in water, without taking ionic strength into account, -The same thing but taking ionic strength into account -pH of 0.00196M solution of HCl in Na2SO4, without taking ionic strength into account, -And...

Homework Statement [/B] Which is more stable cyclobutane or cycloheptane? Homework Equations [/B] [(n-2)180)]/n = angle The Attempt at a Solution [/B] So the closer the angle is to 109.5 the more stable (except for cyclopentane vs cyclohexane). n = number of carbons [(7-2)180)]/7 = 128.57...

Dear friends, I've been having trouble focusing on chemistry with all these boring teachers I get at school. I want some help to increase my interest for chemistry so that I can research about chemistry alone at home. Dear friends, what are the ways I can think of chemistry and how should I...

Is melted bismuth safe to wear pretty much 24/7 around your neck ? I don't want to get a super low radiation hyper bug cancer fungus to appear after 30 yrs... (It touches your skin permanently unless you're running ofc) On top of that, can I smelt bare bismuth (99%) in my kitchen or should I...

Homework Statement How to draw it? Can someone tell me the electronic configuration of the chromium atom in tris( acetylaceato)chromium( III) please Homework Equations N/A The Attempt at a Solution N/A

Homework Statement Suppose that, for reaction 4, you could not find the bottle of 7 M H2SO4 so you added 5.00 mL of the 1.00 M H2SO4 instead. How would this impact your final yield of Copper. (Show with calculations how this would impact the limiting reagent.) Homework Equations CuO(s) +...

Hey. If i carry out electrolysis of saturated sodium bicarbonate solution with lead electrodes, will the lead electrodes will dissolve to form lead carbonate (or basic lead carbonate if temperature is higher) or the lead ions will migrate from anode to cathode and deposite there? I think that...