Carbon dioxide (chemical formula \(CO_2\)) is a colorless and odorless gas vital for life on Earth. Carbon dioxide exists in the Earth's atmosphere as a trace gas at a concentration of about 0.04 percent (400 ppm) by volume. Carbon dioxide is an important greenhouse gas. Burning of carbon-based fuels since the industrial revolution has rapidly increased its concentration in the atmosphere, leading to global warming.

What type of bond has a molecule of carbon dioxide?

The answer is 1 (covalent bond). A covalent bond is the strong electrostatic attraction between two nuclei and the shared pair of electrons between them.


Draw dot-and-cross diagrams to show electrons in \(CO_2\)

Answer 3: 

The carbon atom in the excited state may form four covalent bonds, while the oxygen atom forms two covalent bonds

Intermolecular interactions

What is the nature of intermolecular interactions in aqueous methanol?

In aqueous solution the hydrogen bonds are formed between oxygen in water molecules and hydrogen molecules of the hydroxyl group of methanol, and vice versa.


Select the solvent for 1-chloropropane.

The solvent conforms to the principle that like dissolves like. That is, the polarity substance which must be dissolved and the solvent should be close. 1-chloropropane is dissolved in chloroform and hexane. Halogenoalkanes have no high polarity, so they are soluble in nonpolar and weakly polar solvents.


This figure shows arrangement of atoms in table salt.

Each atom in NaCl is bonded to X other atoms. Table salt has a giant Y structure. In this salt Z atoms are bonded together.

  X Y Z
1 3 ionic all
2 4 covalent none
3 5 metallic some

The correct answer to this question is X-3; Y-ionic; Z-all.


What compound forms a bond with common electron pairs?

The correct answer is \(H_2Se\)


In the lattice of which substance are ions present?

The correct answer is \(BaCl_2\)


In which substance will the molecules form hydrogen bonds?

Methanol will form hydrogen bonds


What is the lattice of sodium sulfate? 



Non-molecular structure has each of two substances:

Potassium and copper have non-molecular structure (metallic lattice).