A glass rod is rubbed with silk, and a plastic rod is rubbed with wool. Afterward, to which object or objects will the glass rod be attracted?

How many electrons make up −1.5 × 10⁻⁵ C?

How many electrons do you have to add to decrease the charge of an object by 16 μC?

Two small aluminum spheres, each having mass $0.0250$ kg, are separated by $80.0$ cm. How many electrons does each sphere contain? (The atomic mass of aluminum is $26.982$ g/mol, and its atomic number is $13$.)

What mass of aluminum has a total nuclear charge of $1.0$ C? Aluminum has atomic number $13$.

What is the total charge of all the electrons in $1.0$ L of liquid water?