Explain why hydrogen gas is given off when a reactive metal undergoes a single-displacement reaction with water.

Consider an electron in the ground-state orbit of the Bohr model of hydrogen. Calculate the current (in amperes) corresponding to the electron's motion.

Write the balanced chemical equation for the reaction of solid calcium with water to form calcium hydroxide in solution and hydrogen gas.

Show that the speed of the electron in the nth Bohr orbit in hydrogen is given by $v _ { n } = \frac { k _ { e } e ^ { 2 } } { n \hbar }$

How many moles of lithium (Li) metal reacts to yield 5 moles of hydrogen gas (H$_2$)?

Consider the Balmer series of spectral lines in the hydrogen atom. What is the smallest wavelength line, in nanometers, in the Balmer series?

Quantitatively compare the rates of effusion for the following pairs of gases at the same temperature and pressure: a. hydrogen and nitrogen, b. fluorine and chlorine

Analyzing Processes Explain why hydrogen gas is given off when a reactive metal undergoes a single-displacement reaction with water.

Use electron-dot symbols to show how a hydrogen atom and a chlorine atom form the diatomic molecule HCl.

An electron in a hydrogen atom changes from the $n=4$ to the $n=3$ state. Determine the wavelength, frequency, and energy of the emitted photon.

Prove that the most probable distance from the proton of an electron in the $2 s$ state of hydrogen is $5.236 a_{\mathrm{B}}-$

Describe how the 21-cm line of hydrogen is formed. Why is this line such an important tool for understanding the interstellar medium?

Which of the following has more atoms: $1. 10 g$ of hydrogen atoms or $14.7 g$ of chromium atoms?

A 10-Hz generator produces a peak emf of 40 V. (a) Write an expression for the emf as a function of time. Indicate your assumptions. (b) Determine the emf at the following times: 0.025 s, 0.050 s, 0.075 s, and 0.100 s. (c) Plot these emf-versus-time data on a graph and connect the points with a smooth curve. What is the shape of the curve?