The amount of a chemical substance is reported as

Options

A. mole
B. mass
C. volume
D. density

Answer

To solve the question regarding how the amount of a chemical substance is reported, we can follow these steps:

### Step 1: Understand the Concept of Moles
The mole is a fundamental unit in chemistry that is used to measure the amount of a substance. It is defined as the amount of substance that contains as many entities (atoms, molecules, ions, etc.) as there are in 12 grams of carbon-12.

**Hint:** Remember that the mole is a counting unit, similar to a dozen, but for particles at the atomic or molecular level.

### Step 2: Identify the Options
The question provides several options: mole, mass, volume, or density. We need to determine which of these is primarily used to report the amount of a chemical substance.

**Hint:** Think about which of these terms is specifically used in stoichiometry and chemical calculations.

### Step 3: Determine the Correct Answer
Among the options given, the mole is the most appropriate unit for reporting the amount of a chemical substance. While mass, volume, and density are important properties of substances, they do not directly represent the quantity of chemical entities.

**Hint:** Recall that in chemical reactions, we often use moles to relate the quantities of reactants and products.

### Step 4: Relate Moles to Mass
To further understand moles, we can use the formula:
\[ \text{Number of moles} = \frac{\text{Mass of the substance (g)}}{\text{Molar mass (g/mol)}} \]
This formula shows how moles relate to the mass of a substance and its molar mass.

**Hint:** Molar mass is a key concept that connects mass and moles, so be sure to know how to calculate it for different substances.

### Final Answer
The amount of a chemical substance is reported as **mole**.