Change Definition and 1000 Threads

Homework Statement Homework EquationsThe Attempt at a Solution 6C-H bonds= 410 x 6 = 2460 kJ/mol 3C-C bonds H of formation= +53.3 kJ/mol H of atomisation = +717 kJ/mol H-H = 436 kJ/mol as H of formation is 53.3, can't I just do: 2460+3x=53.3? But then I am not using a lot of the values...

This is Exercise 2.20 in Nielsen and Chuang's Quantum Computation and Quantum Information, on page 71. Suppose $A'$ and $A''$ are matrix representations of an operator $A$ on a vector space $V$ with respect to two different orthonormal bases, $|v_i\rangle$ and $|w_i\rangle$. Then the elements...

Why isn't the second line in (5.185) ##\sum_k\sum_l<\phi_m\,|\,A\,|\,\psi_k><\psi_k\,|\,\psi_l><\psi_l\,|\,\phi_n>##? My steps are as follows: ##<\phi_m\,|\,A\,|\,\phi_n>## ##=\int\phi_m^*(r)\,A\,\phi_n(r)\,dr## ##=\int\phi_m^*(r)\,A\,\int\delta(r-r')\phi_n(r')\,dr'dr## By the closure...

Homework Statement A sample containing 3.65 mol of a monatomic ideal gas is heated from 289K to 458K, and the entropy remains constant. If the initial volume of the sample was 0.0980m^2, by what factor did the pressure increase or decrease during this process? Homework EquationsThe Attempt at...

Homework Statement Let: ##I=\int _{-1} ^{1}{\frac{dx}{\sqrt{1+x}+\sqrt{1-x}+2}}## Show that ##I=\int_{0}^{\frac{ \pi}{8}}{\frac{2cos4t}{cos^{2}t}}## using ##x=sin4t##. Hence show that ##I=2\sqrt{2}-1- \pi## Homework EquationsThe Attempt at a Solution The substitution is ##x=sin4t## which...

Homework Statement Two moles of an ideal gas undergo a reversible isothermal expansion from 3.37×10−2m3 to 4.29×10−2m3 at a temperature of 29.6 ∘C. What is the change in entropy ΔS of the gas? Homework Equations pV=nRT The Attempt at a Solution W=∫V2V1pdV, I don't know how to use this...

Homework Statement At a moment in time a particle has a velocity of v = 3 m/s î + 4 m/s ĵ, and an acceleration of a = 6 m/s2 î + 3 m/s2 ĵ. Find the rate of change of the speed of the particle, that is, find d|v|/dt. (better formatted reference...

usually, entropy change in solid and liquid is formulated as Cp(or Cv)ln(T2/T1) or Q/T(integral)+ Sgen. so, considering the former and the latter equations, Do their entropy changes include irreversibility due to Sgen? And next question, reservoir has no change in temperature and volume...

My question is: when oil and water from separate containers are poured into the same container and given time to equilibrate, is the entropy change positive, negative, or zero? I've been told that there is zero change in entropy because the water and oil do not mix at all. However, I suspect...

Homework Statement A 20 kg sample of mercury is completely solidified and liberates 231.6 kJ of energy. What is the original temperature of the mercury? (The melting point of mercury is 234K, the heat of fusion of mercury is 11.3 kJ/kg, and the specific heat of mercury is 140 J/kg•K.) . What is...

Good morning everyone! My chemistry final is approaching and I have a few difficulties in the thermodynamics chapter. One of the things that are bothering me is the calculation of the temperature of phase change. We know that if a mole of ice at 273K melts, the entropy change would be...

An ideal gas is compressed from a volume of Vi = 4.50 L to a volume of Vf = 3.00 L while in thermal contact with a heat reservoir at T = 295 K as in the figure below. During the compression process, the piston moves down a distance of d = 0.120 m under the action of an average external force of...

Hello, I have a typesetting software which can export typeset math as normal, nice looking black LaTeX text. However it always puts it on a white background. How can I change the background color of an image (png or jpeg) without changing the black text contained int he image? Should I write...

Homework Statement Assuming water to be an ideal gas, enthalpy of vaporization is x joules per mole. I have to find change in internal energy an 100 degree Celsius for one mole of water. also find heat absorbed. Homework EquationsThe Attempt at a Solution I initially thought that during...

From this diagram: If a conductor of length(##L##) is moving with a velocity(##v##) inside constant magnetic field(##B##), there is an induced EMF as indicated at the top of copper slab, and connected to a load and current will flow. I've been curious with the way the wires are connected to...

have read numerous times about Hawking radiation. don't understand how that can lead to black hole evaporation in so much that wouldn't as many matter as anti-matter particles fall in thus balancing out over time to the growth and evaporation of black holes thus leaving the mass of the balck...

Homework Statement hello, I have a problem that I couldn't find a clear answer to. Attached is a diagram of a related problem that explains the problem Air traveling through two tubes with the same direction have the same PSI (say 75). If you merge the two tubes into a tube with the same...

Homework Statement Find all ##{\cal C}^1(\mathbb{R}_+^\star \times \mathbb{R},\mathbb{R}) ## solutions to the pde ##x\frac{\partial f}{\partial y} - y \frac{\partial f}{\partial x} = cf##, where ##c## is a constant. Use a polar change of variable. Homework Equations Trying to bring the...

I am thinking about something that is getting me quite confused. To illustrate what is confusing me let's have a cart moving in the horizontal direction on a track without friction, and a motor which adjusts to keep the kart at a constant speed V in the positive direction. Now, it's snowing so...

if a ray of monochromatic light comes from a denser medium to a rarer medium does the color reaching a viewer in the rarer medium differ from the actual color of light in the denser medium (as wavelength of light is different for both the media)?

Homework Statement Hvap = 22.6E5 J/Kg. R=8.315E3 Jkmol^-1K^-1. 1kmol water = 18kg Keeping in mind that latent heats are enthalpies, what is the change in internal energy when 1kg water is converted to steam at pressure of 1atm and temperature of 100C. Homework Equations dU = dQ - PdV. The...

Homework Statement What is the entropy change of the universe as a result of the following processes: (a) a 1μF capacitor is connected to a 100V electrochemical cell at 0°C, (b) the same capacitor after being charged to 100V is discharged through a resistor kept at 0°C? Homework Equations...

Homework Statement All edges of a cube are expanding at a rate of 3 centimeters per second. How fast is the volume changing when each edge is (a) 1 centimeter and (b) 10 centimeters? Homework EquationsThe Attempt at a Solution I used the equation for the volume of a cube: V = s3 but I'm not...

Hello everyone, I still wonder if there's a change in entropy in adiabatic process. The definition of entropy is a quantity represents for the disorder state of a system. Arccording to kinetic theory of gas, temperature is for the state of chaotic motion of molecules. So I'm very confuse, can...

Homework Statement [/B] Consider ##\mathbb{R}^3## in standard Cartesian co-ordinates, and the surface ##S^2## embedded within it defined by ##(x^2+y^2+z^2)|_{S^2}=1##. A particular set of co-ords on ##S^2## are defined by ##\zeta = \frac{x}{z-1}##, ##\eta = \frac{y}{z-1}##. Express...

I believe I can explain why there is energy needed to break intermoleculares bonds and getting into a gas or liquid, but the other way around confuses me. Bonds have potential energy associated to it, so It's needed work to break the bonds, because we would be trying to move a molecule away from...

Homework Statement to illustrate an aspect of the second law of thermodynamics, we regard entropy changes in two cases. We have a vessel with 1 kg of warm water with T = 80 C and another vessel with 2 kg of cold water with T = 10 C and we mix them. Case 1: we pour hot water in the vessel with...

So let me start with my high school habits. Basically I never cared about school. Always more concerned with my current girlfriend than getting good grades. I actually dropped out because of one of them, and cashed in my California High School Proficiency Certificate my senior year. One of the...

Homework Statement A 178.0g ball is dropped from a height of 2.99m, bounces on a hard floor, and rebounds to a height of 1.36m. The impulse received from the floor is shown below. (Is a picture of a graph, Y-axis is force, X-axis is time. No numbers are labelled and is simply a line starting...

Homework Statement UV Rays is said to induce point mutations which get incorporated during the DNA replication process. These mutations are corrected by the excision repair mechanism of the DNA polymerase but sometimes they might be left out. In one of such cases, point insertions were...

How can I prove that the entropy change is intrinsically positive? Given two systems with both of the heat capacities are independent of temperature.

Homework Statement [FONT=Courier New]The formula for price elasticity in my micro/macroeconomics course is: elasticity = For those unable to view the image: (change in quantity / avg quantity)/(change in price / avg price) My question is: Why is it that the average quantity/price is used...

I am familiar with the proton:neutron ratio and stability but what about this instability actually causes a quark to emit a boson and change flavour? And what does this have to do with the weak nuclear force? Thanks

Hi, I am basically 45 years old postgraduate in statistics but, unfortunately, I joined private manufacturing company and worked there for 20 years. Now I have resigned from a job and searching new opportunities. But it is very difficult to get a job as industry won't accept me due to the...

I attached picture. I took the F=GMm/r^2 equation and did it for both Earth level, (radius of earth) with 650/9.8 as m and for F at the top of the building, with r being the radius of the Earth plus a mile (1.609E3 m). Please help?

Homework Statement Refer to plot attached. Homework Equations (a)Find the work done by a monatomic ideal gas as it expands from point A to point C along the path shown in the figure. (The horizontal axis is marked in increments of 25 m3.) (b) If the temperature of the gas is 215 K at point A...

Homework Statement A heat engine operates between a high-temperature reservoir at 634 K and a low-temperature reservoir at 320 K. In one cycle, the engine absorbs 6540 J of heat from the high-temperature reservoir and does 2200 J of work. Homework Equations What is the magnitude of the net...

Suppose we have ##a \equiv 0 (mod~ m)##. And, ## a \equiv b (mod~ n)##. Is there any way to relate ##b## with ##m## and ##n## ?

Homework Statement The center of a 1.00 km diameter spherical pocket of oil is 1.00 km beneath the Earth's surface. Estimate by what percentage g directly above the pocket of oil would differ from the expected value of g for a uniform Earth? Assume the density of oil is 8.0*10^2 (800) kg/m^3...

Write a differential formula that estimates the change in the volume $V=\frac{4}{3}\pi{r}^{3}$ of a sphere when the radius changes from $r_0$ to $r_0+dr$ $$dV=4\pi{r}_{0}^{2}dr$$ this was one of the selections but I didn't know how to account for the $r_0$ to $r_0+dr$

Homework Statement in figure b , based on the direction of moment of anticlockwise is positive , i can say that -Tcos20 (7 sin 30 ) is a clockwise moment , so that the tension of rope should be acted in upward direction , so that the horizontal component of the force acted to the left to...

In class we derived the relationship between temperature and heat capacity for the Debye model. We found that in 3D the heat capacity is proportional to temperature cubed. My question is, would this relationship change in a metallic system?

Hi! This is my first post and I'm hoping to receive so help :D If f(x)=\frac{1}{{x}^{2}+1}. The rate of change of f at a is defined as \lim_{{h}\to{0}}\frac{f(a+h)-f(a)}{h}. In case, these commands don't work properly... the question is: if f(x)=1/(x^2+1) and rate of change of f at a is defined...

Hey! :o What could we change at the following definition so that $\text{EXP}(\mathbb{C})$ is a ring? "We define EXP($\mathbb{C}$) to be the the set of expressions \begin{equation}\label{a} a=\alpha _0+\alpha _1e^{\mu_1z}+\dots +\alpha _Ne^{\mu_Nz} \end{equation} (beyond the `zero...

Homework Statement Consider the apparatus that Joule used in his experiments on the mechanical equivalent of heat, shown in the figure below. Suppose both blocks have a mass of 0.69 kg and that they fall through a distance of 0.45 m. Homework Equations (a) Find the expected rise in temperature...

Homework Statement See pictures. There are 2 parts to the problem but I can probably figure out the second part once I get the first part. [/B] Homework Equations Antinodes (minimum pressure) at Nodes (maximum pressure) at [/B] Equation for a standing wave: The Attempt at a Solution...

1 kg of iron with the temperature of 323 K to 293 K is cooled by dipping into a large water bath temperature of 293 K. What is the total entropy change?Relevant equations dS = mcdT/T S=mc *ln(T2/T1) C iron = 450J/(kgK) C water= 4200 J/(kgK) m water = I see in my book 1 kg in solution The...

Homework Statement [/B] Change the independent variable from x to θ by x=cosθ and show that the Legendre equation (1-x^2)(d^2y/dx^2)-2x(dy/dx)+2y=0 becomes (d^2/dθ^2)+cotθ(dy/dθ)+2y=0 2. Homework Equations The Attempt at a Solution [/B] I did get the exact form of what the equation...

Assume that you are given a coordinate change on a line which changes the coordinate x to a new coordinate z given by the formula z=U⋅x+P where U,P are real numbers with U non zero. If the new coordinate of the point -13 is 12 and the new coordinate of the point -7 is 6 then we must have U= ...

1. Homework Statement Express the beam energy loss in the accelerator in terms of the change in the beam momentum. It is taken from one paper, where \begin{equation} \Delta T = \left( \frac{1+\gamma}{\gamma}\right) \frac{T_0 \Delta p}{p_0} \end{equation}expression is used for transition from...