The Heisenberg uncertainty principle can be expressed in the form $$\Delta E \cdot \Delta t \geq \frac{h}{4 \pi}$$ where \(E\) represents energy and \(t\) represents time. Show that the units for this form are the same as the units for the form used in this chapter: $$\Delta x \cdot \Delta(m v) \geq \frac{h}{4 \pi}$$

Short Answer

Expert verified
In the given forms of the Heisenberg Uncertainty Principle, for the first form \(\Delta E \cdot \Delta t \geq \frac{h}{4 \pi}\), the units are Joule-seconds (J·s), while for the second form \(\Delta x \cdot \Delta(mv) \geq \frac{h}{4 \pi}\), the units can be converted into Joule-seconds as well (J·s). Therefore, the units for both forms are the same.

Step by step solution

01

Identify the units for each variable

First, we should determine the units for each variable in SI units: - \(E\): Energy, measured in Joules (J) - \(t\): Time, measured in seconds (s) - \(x\): Position, measured in meters (m) - \(m\): Mass, measured in kilograms (kg) - \(v\): Velocity, measured in meters per second (m/s) - \(h\): Planck's constant, measured in Joule-seconds (J·s)
02

Analyze the first form, \(\Delta E \cdot \Delta t \geq \frac{h}{4 \pi}\)

Now that we have determined the units for each variable, let's analyze the units for each term in the first form of Heisenberg Uncertainty Principle: $$\Delta E \cdot \Delta t \geq \frac{h}{4 \pi}$$ Substitute the SI units for the variables: $$\Delta(\text{J}) \cdot \Delta(\text{s}) \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$ Simplify: $$\text{J} \cdot \text{s} \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$
03

Analyze the second form, \(\Delta x \cdot \Delta(mv) \geq \frac{h}{4 \pi}\)

Now let's analyze the units for each term in the second form of Heisenberg Uncertainty Principle: $$\Delta x \cdot \Delta(mv) \geq \frac{h}{4 \pi}$$ Substitute the SI units for the variables: $$\Delta(\text{m}) \cdot \Delta(\text{kg} \cdot \frac{\text{m}}{\text{s}}) \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$ Simplify: $$\text{m} \cdot (\text{kg} \cdot \text{m}/\text{s}) \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$ Now, we need to convert the left-hand side of this inequality to Joule-seconds. Recall that the relationship between Joules, kilograms, and meters is given by the formula \(E = \frac{1}{2}mv^2\). So, we can substitute \(\text{J} = \text{kg} \cdot (\text{m}/\text{s})^2\): $$\text{m} \cdot (\text{kg} \cdot \text{m}/\text{s}) = \text{J} \cdot \text{s}$$
04

Compare the units of both forms

From steps 2 and 3, we have the following inequalities: Inequality 1: $$\text{J} \cdot \text{s} \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$ Inequality 2: $$\text{J} \cdot \text{s} \geq \frac{\text{J} \cdot \text{s}}{4 \pi}$$ It can be seen that the units on both sides of the inequalities in step 2 and 3 are the same, which means that both forms of the Heisenberg Uncertainty Principle have the same units and are consistent with each other.

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Most popular questions from this chapter

Identify the following elements. a. An excited state of this element has the electron configu- ration 1$s^{2} 2 s^{2} 2 p^{5} 3 s^{1}$ b. The ground-state electron configuration is [Ne \(] 3 s^{2} 3 p^{4}\) . c. An excited state of this element has the electron configu- ration \([\mathrm{Kr}] 5 s^{2} 4 d^{6} 5 p^{2} 6 s^{1}\) d. The ground-state electron configuration contains three unpaired 6\(p\) electrons.

Which of the following sets of quantum numbers are not allowed? For each incorrect set, state why it is incorrect. a. \(n=3, \ell=3, m_{\ell}=0, m_{s}=-\frac{1}{2}\) b. \(n=4, \ell=3, m_{\ell}=2, m_{s}=-\frac{1}{2}\) c. \(n=4, \ell=1, m_{\ell}=1, m_{s}=+\frac{1}{2}\) d. \(n=2, \ell=1, m_{\ell}=-1, m_{s}=-1\) e. \(n=5, \ell=-4, m_{\ell}=2, m_{s}=+\frac{1}{2}\) f. \(n=3, \ell=1, m_{\ell}=2, m_{s}=-\frac{1}{2}\)

An ion having a \(4+\) charge and a mass of 49.9 u has 2 electrons with principal quantum number \(n=1,8\) electrons with \(n=2\) and 10 electrons with \(n=3 .\) Supply as many of the properties for the ion as possible from the information given. (Hint: In forming ions for this species, the 4\(s\) electrons are lost before the 3\(d\) electrons.) a. the atomic number b. total number of \(s\) electrons c. total number of \(p\) electrons d. total number of \(d\) electrons e. the number of neutrons in the nucleus f. the ground-state electron configuration of the neutral atom

When the excited electron in a hydrogen atom falls from \(n=5\) to \(n=2,\) a photon of blue light is emitted. If an excited electron in He \(^{+}\) falls from \(n=4,\) to which energy level must it fall so that a similar blue light (as with the hydrogen) is emitted? Prove it. (See Exercise \(174 . )\)

Consider the following ionization energies for aluminum: $$\begin{array}{c}{\operatorname{Al}(g) \longrightarrow \mathrm{Al}^{+}(g)+\mathrm{e}^{-} \quad I_{1}=580 \mathrm{kJ} / \mathrm{mol}} \\\ {\mathrm{Al}^{+}(g) \longrightarrow \mathrm{Al}^{2+}(g)+\mathrm{e}^{-} \quad I_{2}=1815 \mathrm{kJ} / \mathrm{mol}} \\ {\mathrm{Al}^{2+}(g) \longrightarrow \mathrm{Al}^{3+}(g)+\mathrm{e}^{-} \quad I_{3}=2740 \mathrm{kJ} / \mathrm{mol}} \\ {\mathrm{Al}^{3+}(g) \longrightarrow \mathrm{Al}^{4+}(g)+\mathrm{e}^{-} \quad I_{4}=11,600 \mathrm{kJ} / \mathrm{mol}}\end{array}$$ a. Account for the trend in the values of the ionization energies. b. Explain the large increase between \(I_{3}\) and \(I_{4}\)

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