1. Which of these chemical formulasCl2, KCl, Ar, or NO2represents both an element and a molecule?

2. A miner finds a small mineral fragment with a volume of 5.74 cm3 and a mass of 14.4 g. What is the density of that mineral fragment?

Ar is an element. It also is a molecule.

From the way the question is worded, I'm tempted to pick Cl2 also; however, Cl is the element and Cl2 is the molecule. For that reason I'm not including it.

#2. density = mass/volume.

1. To determine which chemical formula represents both an element and a molecule, let's go through each option:

- Cl2: This represents a diatomic molecule of chlorine, which is made up of two chlorine atoms bonded together. Therefore, this formula represents both an element (chlorine) and a molecule.
- KCl: This represents one potassium atom bonded with one chlorine atom. While it does represent a compound, it does not represent a molecule of an element.
- Ar: This formula represents argon, a noble gas. As noble gases exist as single atoms and are not capable of forming molecules, this formula represents only an element, not a molecule.
- NO2: This formula represents a molecule of nitrogen dioxide, which consists of one nitrogen atom bonded with two oxygen atoms. Although it represents a molecule, it does not represent an element, as it includes multiple types of atoms (nitrogen and oxygen).

Therefore, the chemical formula Cl2 represents both an element (chlorine) and a molecule.

2. Density is defined as the mass of an object divided by its volume. To find the density of that mineral fragment, we need to use the given mass and volume information.

Density (D) = Mass (m) / Volume (V)

In this case, the mass is given as 14.4 g and the volume is given as 5.74 cm3. To calculate the density, simply divide the mass (14.4 g) by the volume (5.74 cm3):

D = 14.4 g / 5.74 cm3

Performing the calculation, we find that the density of the mineral fragment is approximately 2.51 g/cm3.