# application of second order differential equation in chemistry

We have already mentioned that the response type shown in Fig. 42 should be done in the limits of $$N_{0}$$ (initial number of radioactive atoms) and $$N_{\text{f}}$$ (final number of radioactive atoms), when the time runs from 0 to $$t$$: Equations 39 and 40 show that generally it holds that. per definition in z-direction ($$M_{z}$$). 70 also as follows: Equation 72 is a nonhomogeneous linear first-order differential equation. 5c is observed in many experimental cases. Then, a 90° pulse is necessary to enable the signal detection in y-direction. These equations are the most important and most frequently used to describe natural laws. It can be calculated by $$v_{{{\text{response (}}\tau )}} = \tau \cdot f$$, where $$f$$ is the flow rate, e.g. i Correspondence to For the latter two situations the reader is advised to consult textbooks of chemical kinetics (e.g. Here, it may suffice to mention some possible time depending processes which can contribute to the measured time constant: (a) diffusion of particles towards the sensing surface (e.g. Therefore, in this case, $\alpha_{1,2}=\frac{-k_1\pm \sqrt{k_{1}^{2}-4k_2}}{2}=\frac{-k_1\pm i \sqrt{-k_{1}^{2}+4k_2}}{2} \nonumber$. The other initial condition is $$y'(0)=-1$$: $y'(0)=b+4=-1\rightarrow b=-5 \nonumber$, The particular solution, therefore, is $$y(x)=(1-5x)e^{4x}$$, This video contains an example of each of the three cases discussed above as well as the application of the method of reduction of order to case III. The constants $$a$$ and $$b$$ are arbitrary constants that we will determine from the initial/boundary conditions. κ is a value specific for the particles and specific for the photon energy E 67 and 68 in Eq. This text was written to present a unified view on various examples; all of them can be mathematically described by first-order differential equations. 72 is then the sum of the solution of the homogeneous differential equation $$q_{\text{h}} (t)$$ and the particular solution $$q_{\text{p}} (t)$$, i.e. Felix Bloch [11] described two different relaxation processes with (i) the spin–lattice or longitudinal relaxation time $$T_{1}$$, describing the relaxation in the direction of the external magnetic field B Most electrochemical techniques make use of a changing electrode potential (linear and non-linear) to measure the current response. helium-4 nuclei; beta particles, i.e. In this case, $$\sqrt{k_{1}^{2}-4k_2}>0$$, and therefore $$\alpha_1$$ and $$\alpha_2$$ are both real and different. 54). = {\displaystyle P} 1 ξ However, ... Second order linear equations occur in many important applications. Of course, one can also calculate the response volumes relating to 90 or 99 % of the signal, i.e. Let’s replace $$y(x), y'(x)$$ and $$y''(x)$$ in the differential equation: $\alpha^2e^{\alpha x}-5 \alpha e^{\alpha x} +4 e^{\alpha x}=0 \nonumber$, $e^{\alpha x}\left(\alpha^2-5 \alpha + 4 \right)=0 \nonumber$. The second initial condition is $$y'(0)=-1$$. the metal wires, have a much lower resistance than the electrolyte solution. We’ll analyze what the different parts of this equation mean in the examples. The method of reduction of order gives: Since we accepted the result of the method of reduction of order without seeing the derivation, let’s at least show that this is in fact a solution. \kern-0pt} {{\text{d}}t}})_{\text{limit}} \). This means, when the temporal response properties of a sensor are studied, this concentration rise has to be much quicker than the response of the sensor. \kern-0pt} {RC}}}} + C \cdot \Delta E $$,$$ q = C \cdot \Delta E(1 - {\text{e}}^{{ - {t \mathord{\left/ {\vphantom {t {RC}}} \right. a one-dimensional device where no parameters like $$x$$ or $$y$$ are changed, the time change of the signal can be studied following a concentration step. Since any measurement needs time, there is nothing like an instantaneous establishment of a signal. Google Scholar, Hellberg D, Scholz F, Schubert F, Lovrić M, Omanović D, Agmo Hernández V, Thede R (2005) J Phys Chem B 109:4715–14726, Article  According to Kirchhoff’s law, the overall potential difference across the resistor and capacitor is the sum of two potential drops: For the potential drop across the resistor follows (Ohm’s law): where $$R$$ is the solution resistance and $$I$$ the current. 2: Integration of Eq. In this case, $$k_{1}^{2}-4k_2<0$$, so , $$\sqrt{k_{1}^{2}-4k_2}=i \sqrt{-k_{1}^{2}+4k_2}$$ where $$\sqrt{-k_{1}^{2}+4k_2}$$ is a real number. \kern-0pt} {RC}}}} , $${{\Delta E} \mathord{\left/ {\vphantom {{\Delta E} R}} \right. Clearly, the effectivity of capture must be proportional to the number of particles per volume, i.e. Table 1 gives an overview of the discussed cases of application of first-order differential equations to chemistry. \kern-0pt} {{\text{d}}t}}$$ may give a reproducible and identical response only below a certain limiting rate $$({{{\text{d}}x} \mathord{\left/ {\vphantom {{{\text{d}}x} {{\text{d}}t}}} \right. The mathematical solution of the differential equations (Eq. 5b is to some extend an idealization, and in reality there may be always a sluggish response at the start, but it may be on such short time scale that it escapes our recognition. The first and second derivatives are: $y'(x)=be^{4 x}+4(a+bx)e^{4x} \nonumber$, $y''(x)=4be^{4 x}+4be^{4x}+16(a+bx)e^{4x} \nonumber$. But this is too restrictive because we want to find a solution that is a function of \(x$$, so we don’t want to impose restrictions on our independent variable. 54) for the determination of the spin–spin (or transversal) relaxation time $$T_{2}$$ is obvious and is exemplarily given for the time-dependent behaviour of the magnetization $$M_{y}$$ in $$y$$-direction (cf. Here, we shall discuss the most simple case: two metal pieces are inserted in an electrolyte solution, e.g. Chemical reaction kinetics is the study of rates of chemical processes (reactions). $$v_{{{\text{response (}}\tau )}} = t_{90\% } \cdot f$$ or $$v_{{{\text{response (}}\tau )}} = t_{99\% } \cdot f$$, respectively. 5b with a scale giving the response in percentage. The equation above is homogeneous if $$F(t)=0$$. The differential decrease −dI of radiant flux by passing through the differential length increment dx is supposed to be proportional to the actual value of I at x Legal. An examination of the forces on a spring-mass system results in a differential equation of the form $mx″+bx′+kx=f(t), \nonumber$ where mm represents the mass, bb is the coefficient of the damping force, $$k$$ is the spring constant, and $$f(t)$$ represents any net external forces on the system. 10). Solving second order ordinary differential equations is much more complex than solving first order ODEs. The response volumes of a flow-through detector can be larger or also smaller than the geometric volume of the detector. in optical sensors as used in chromatography), (c) chemical reactions, esp. here y, having the exponent 1, rendering it a linear differential equation, and (iii) there are only terms containing the variable y and its first derivative, rendering it a homogeneous ChemTexts Thus, it is much less important to exactly describe the complete response curve from beginning to the end, which would be only possible by solving higher-order differential equations and characterizing the response by more than one time constant. Mathematically, this means that if $$y_1(x)$$ and $$y_2(x)$$ are solutions, then $$c_1 y_1(x)+c_2 y_2(x)$$ is also a solution, where $$c_1$$ and $$c_2$$ are constants (i.e.

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