Approximately how many atoms are present in a gram of water?

A particular atom contains 29 electrons, 34 neutrons, and 29 protons. What is the identity of this element, and what is its atomic number?

The mass numbers of two isotopes of cobalt are 59 and 60. (a) How many protons and how many neutrons are in each isotope? (b) How many orbiting electrons does an atom of each have when the atoms are electrically neutral?

How many atoms are in a molecule of sulfuric acid, $\mathrm{H}_2 \mathrm{SO}_4 ?$

What is the cause of the Brownian motion of dust and other small particles? Why aren't larger objects, such as baseballs, similarly affected?

Your friend says that what makes one element distinct from another is the number of electrons around the atomic nucleus. Do you agree wholeheartedly, partially, or not at all? Explain.

Which of the following are pure elements: $\mathrm{H}_2, \mathrm{H}_2 \mathrm{O}, \mathrm{He}$, $\mathrm{Na}, \mathrm{NaCI}, \mathrm{H}_2 \mathrm{SO}_4, \mathrm{U}$ ?

Which of the following is not an element: hydrogen, carbon, oxygen, water?

What are the type of speeds at which atoms and molecules in the atmosphere move? Could you say that we are breathing one another?

The average speed of a perfume-vapor molecule at room temperature may be about $300 \mathrm{~m} / \mathrm{s}$, but you'll find the speed at which the scent travels across the room is much less. Why?

When a container of gas is heated, would you expect its molecules to speed up, slow down, or be unaffected?

How many individual atoms is an $\mathrm{H}_2 \mathrm{~S}$ molecule composed of?

What is the difference between an element and an atom? Name the lightest element.

Rank the masses of these molecules from greatest to least.

$\mathrm{O}_2$, $\mathrm{H}_2\mathrm{O}$, $\mathrm{CH}_4$ and $\mathrm{NH}_3$.