Equilibrium Definition and 1000 Threads

Homework Statement Excess BaCO3 is placed in a container containing 5L of pure water. Given the following info: BaCO3 (s) ↔ Ba2+ + CO3 2- and Kc = 5.7E-6 how many moles of BaCO3 dissolve? Homework Equations Kc=(Ba2+ )(CO3 2- ) = 5.7E-6 The Attempt at a Solution solved for x to get .002387...

Moving fluids are generally in a state of non-equilibrium. However, in fluid dynamics, people generally assume a state of local thermodynamic equilibrium and argue that in such a condition, equilibrium thermodynamic concepts such as pressure, temperature, entropy, internal energy etc. can be...

I am wondering the answer to the following question, and what equation you would use to solve it: What is the duration of the following reversible reaction? A <--> B You have 10 moles of A and zero moles of B. After 1 minute, 25% of A turns into B, and 50% of B turns into A. My class...

Homework Statement A non-uniform box sits on two scales as seen below. Scale A reads 10.2N, and scale B reads 19.4N. Question: How far from the left end of the box is the center of mass located? Homework Equations τccw=τcw τ=f*d(from pivot point) The Attempt at a Solution If I choose the...

Many introductory (high school chemistry) texts speak of reactions that are “always” or “never” spontaneous (in the former case they reference reactions where ∆H is - and ∆S is +, for example). I struggle with this concept when considering reactions in closed systems. Premise: All reactions...

The book says when the water is heated, the pressure stays constant. But I do not understand pressure for a liquid-water system. What is the pressure for a liquid here? the pressure on the surface, botton or sides? Source: Fundamentals of Thermodynamics by Sonntag/Borgnakke/Van Wylen. Thank you.

Homework Statement 8. A 20 kg uniform beam 10m long is attached to a wall with a cable. The cable is attached to the middle of the beam at a 90 degree angle to the beam. A box of mass 5 kg is also suspended from the beam. In addition to this, the beam is attached to the hinge at the bottom...

Homework Statement A vertical cylinder of radius r contains an ideal gas and is fitted with a piston of mass m that is free to move. The piston and the walls of the cylinder are frictionless, and the entire cylinder is placed in a constant-temperature bath. The outside air pressure is p0. In...

Homework Statement Problem 132 Homework Equations Not sure. I know we will use Kc=[Products]/[Reactants] The Attempt at a Solution I tried to devise a balanced equation to use: AuCl (s) + NaCl (s) + H2O (l) → Au+ + 2Cl- + Na+ and then try solving from there

Hi all, If I have a hot object in space (not a star but say an oven or just a hot gas as would be on Earth < 10,000 degrees Kelvin) glowing at a temperature T and I want to know long it takes to come to equilibrium with the vacuum of space around it, how can I calculate such a time? I could...

Homework Statement This problem is found in The Exercises for the Feynman Lectures on Physics: A flat steel plate floating on mercury is acted upon by three forces at three corners of a square of side 0.100 m. Find a single fourth force which will hold the plate in equilibrium. Give the...

I have solved this question by completely disregarding the reaction at the hinge B. And surprisingly, answer turns out to be correct. Why is that so?

Homework Statement Given the reaction, at equilibrium, it was found that [C] = 0.20 mol/L, [D] = 0.55 mol/L, [A] = 0.30 mol/L and [ B] = 0.48 mol/L. Calculate the value of Keq. Reaction: C + D <--> A + B Homework Equations K=products/reactants The Attempt at a Solution [/B] If we assume that...

I do not understand how to calculate the equilibrium price of an object. Say i have the following information how would i set up the information to solve for the price? Price of (Insert the name of your good or service) Quantity Demanded Quantity Supplied (in this order.) \$7.99, 35, 21...

Homework Statement Consider a mass attached to four identical springs, as shown in the figure. Each spring has a force constant k and an unstretched length lo, and the length of each spring when the mass is at equilibrium at the origin is a (not necessarily the same as lo). When the mass is...

Homework Statement A spherical drop of a pure substance floats on top of the vapor of the same substance so the system vapor+drop is isolated. The drop has a surface tension σ. Show that at the thermodynamic equilibrium PL≠PV and calculate the difference. Homework Equations Three laws of...

Homework Statement Two ladders, 4.00 m and 3.00 m long, are hinged at point A and tied together by a horizontal rope 0.90 m above the floor (Fig. P11.89). The ladders weigh 480 N and 360 N, respectively, and the center of gravity of each is at its center. Assume that the floor is freshly waxed...

I have a good understanding on the hall effect. However, I was told by my tutor that the electric field direction at equilibrium remains pointing in the negative side of the conducting material and the force it generated is canceled out. But further reading online text, the electric field...

Dear all, for the topic https://www.physicsforums.com/threads/problems-with-the-theory-of-inflation.905230/ I came across the following paper: https://arxiv.org/abs/1505.01456. In this paper the following arguments are given why the horizon problem is a fake problem. It raised by me the...

The question I am asking comes from a side issue in another thread. I am seeking an explanation that will explain my wrong understanding of the physics. https://www.physicsforums.com/threads/q-re-wiki-equation-for-t-x-t-2.903984 In post #19 of the above thread I describe my uncertainty about my...

Homework Statement Suppose the weight of the drawbridge in Figure is supported entirely by its hinges and the opposite shore, so that its cables are slack. (a) What fraction of the weight is supported by the opposite shore if the point of support is directly beneath the cable attachments? (b)...

$\tiny{9.4.5}$ $$y'=\sqrt{5},y>0$$ Identify the equilibrium values which are stable and unstable? I assume 0 is the only one

Homework Statement Here are the problem statement and the solution. I'm stuck at where the book suggests the formulas for the x and y coordinations (highlighted in yellow) of the third charge. Any explanations or proof on how they came to the conclusion for the third charge coordinations would...

Homework Statement [moderator note: Post edited to make problem statement images visible] https://www.physicsforums.com/attachments/question-jpg.113056/ My question is when forces are resolved horizontally, why is the friction force at A not taken into account? The Attempt at a Solution...

Homework Statement If the load on the uniform beam shown below is moved to the left, how do the tension force T and the magnitude of the vertical force Fv exerted by the wall on the hinge change? The answer is A Homework Equations torque = Fdsin(theta) The Attempt at a Solution My equation...

I have a 3 pulley system statically balanced hanging weights at a determined relative angle (we are taking into account friction). If I change the position of one pulley, angles will remain the same. However, if I have a 4 pulley system, at the same conditions, changing one's position will...

Homework Statement This is a real world application. I am posting it here to follow the guideline for any "coursework-like" questions, but since I have no formal training, I'm not sure what category this would actually fall under. Any recommendations for a more specific posting location would...

Homework Statement Let's consider conduction electrons (at T=0K) that are put in a magnetic field. The electrons can have spin that is parallel or antiparallel to the magnetic field. Below is the density of occupied states for such a system (horizontally) as a function of energy (vertically)...

Homework Statement If a block of 250 grams of lead (specific heat (c) =130) at 315 degrees celsius is placed in a 200 gram aluminum (c=900) calorimeter cup containing 900 grams of water (c=4.1), and the calorimeter and the water are both initially at 15 degrees celsius, what is the equilibrium...

Homework Statement You would like to put a solar hot water system on your roof, but you're not sure it's feasible. A reference book on solar energy shows that the ground-level solar intensity in your city is 750 W/m^2 for at least 5 hours a day throughout most of the year. Assuming that a...

Hello everybody, I've got a gap in my understanding regarding NMR systems, and I hope you can help: if the magnetisation of a proton is M0 in the Mz direction initially, a 90ox-RF-pulse will change the magnetisation to M0 in the My direction immediately after the pulse. But what happens when a...

Homework Statement "A well-insulated bucket of negligible heat capacity contains 120 g of ice at 0°C. If 20 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system?" Homework Equations $$Q_{fus} = m_{water}L_{fus}$$ $$Q_{vap} =...

Homework Statement The original question was to find the value of the angle between PA and AB. I have a certain idea regarding how to find it, but first I have to identify all forces acting on the system and their directions. So, I would be grateful if someone can explain how the frictional...

Homework Statement What is the maximum [CO32-] that can exist in a saturated solution of AgBr? Homework Equations Equilibrium Constants, ICE tables sqrt = square root The Attempt at a Solution Ksp = [Ag+][Br-] sqrt(5.4E-13) = x (Ag and Br are in equal proportion to one another) where x...

Homework Statement Hello. Given the statically determinate truss shown in the image, solve for all forces in the members, in terms of the load P. Homework Equations Equations of equilibrium. Node analysis. Section analysis. The Attempt at a Solution I was able to solve it by solving first...

Can someone explain why when you increase the temperature on an endothermic reaction, it yields more products? Is it because the activation energy is higher in an endothermic reaction, so there is more time for the products to form? also why does decreasing the temperature yield more products in...

1. Homework Statement This isn't really a problem but an example in an online lecture. I'm trying to understand everything for when I get to harder questions but am having trouble understanding the "d/b" part of the equation. Homework Equations How does dividing d by b help solve for the...

Homework Statement Consider the rod as shown in the figure. The coefficient of static friction at A and B is \mu_s. I'm trying to find how big and how small the ratio l/d can be for the rod to still be in equilibrium. I have calculated how big all forces are acting upon the rod in the case...

Homework Statement To unclog a drain you add 26g of sodium hydroxide to 150mL of water. Calculate the pH and pOH for the solution you prepared. Can someone tell me if I'm doing it right. Homework EquationsThe Attempt at a Solution n = m/M n = 26/40 n = 0.65mol for 0.15L Does this mean that I...

Homework Statement For this experiment we studied the equilibrium system CuCl42+(aq) ↔ Cu2+ + 4Cl-(aq) + heat Net reaction shift is observed by looking at colour changes -CuCl42+(aq) become green (shift to left) - Cu2+ is blue and Cl-(aq) is colourless (shift to right) What occurs when you put...

Homework Statement N2O4(g) + energy <---> 2NO2(g) How are Keq and [N2O4] affected by the addition of Ne, an inert gas, in a container at constant volume and temperature. Keq [N2O4] a) no change/no change b) no change/ increases c) increases/decreases d) decreases/increases Homework...

Usually, the pendulum problems I encounter relate to initial velocity. What happens if, at equilibrium, I push a pendulum with a certain amount of force? (E.g. 10N) Is there a way to calculate how high the pendulum will go? I guess it's complicated considering torque done by gravity, etc

Homework Statement Calcium carbonate primarily occurs as two crystalline forms, calcite and aragonite. The value of∆!° for the transition CaCO3(calcite) ⇌ CaCO3(aragonite) is +1.04 kJ·mol-1 at 25°C. At that temperature the density for calcite is 2.710 g·cm-3, and that of aragonite is 2.930...

Hi Everyone, I am having trouble grasping the concept of Raoult's law, partial pressures etc. One problem in specific is: A system contains 3 moles of methanol and 7 moles of water at 25 degrees celsius. The temperature is raised until there is 40 mol% methanol in the gas phase. How much is...

Hi everyone, I plan to do a simulation of a Boltzmann equation with experimentally known scattering between two particles. Initially I intend to incorporate the scattering into the collision integral and use Lattice Boltzmann Equation (LBE) afterwards. But I only see LGBK (DnQb) which requires...

Homework Statement Equal Volumes of 3.60 M A2+ and 6.80 M B- are mixed. After the reaction, equilibrium is established with [B-] = 0.40 M. What is the [A2+] at equilibrium? Homework Equations Ice table, algebra The Attempt at a Solution This is probably a really easy problem, but I seem to be...

Homework Statement The Reaction Fe3O4(s) + CO(g) ↔ 3 FeO(s) + CO2(g) took place at 600°C and at a constant total pressure of 5.00 atm. Determine the amount of each substance at equilibrium if there were 1 mole of Fe3O4, 2 moles of CO, .5 moles of FeO, and .3 moles of CO2...

Hello, for those who don't know me I'm layman with some knowledge at popular science level. Discussing with a friend we came to the following point and I would like to ask it here because we had doubts about our reasoning. Cramer's Transactional Interpretation proposes that, in a sense, a...

Homework Statement A human holds a ball of mass 8kg at his hand, so that the forearm is perpendicular to the upperarm. The distance between the elbow and the center of mass of the forearm is 0.15 meters, the distance between the elbow and the muscle is 0.05 meters and the mass of the forearm...

Homework Statement Find the angle Theta so that the system is in equilibrium Mass of each block: 2 Kg Mass of ring: 4π Kg Homework Equations Static equilibrium: Rotational equilibrium The Attempt at a Solution Static equilibrium: 2g + 2g + 4πg = Normal N = 4g + 4πg Taking...