Quiz on Apologia Chemistry Module 5

What is the chemical formula for sulfate?

• SO₄²⁻

• ClO₂⁻

• C₂H₃O₂⁻

• S²⁻

Answer explanation

The chemical formula for sulfate is SO₄²⁻, which indicates it has a sulfur atom bonded to four oxygen atoms and carries a -2 charge. The other options represent different ions and are not sulfate.

What is the chemical formula for dichromate?

• S²⁻

• Cr₂O₇²⁻

• PO₄³⁻

• SO₄²⁻

Answer explanation

The chemical formula for sulfide is S²⁻, which represents the sulfide ion with a charge of -2. The other options represent different ions: Cr₂O₇²⁻ (dichromate), PO₄³⁻ (phosphate), and SO₄²⁻ (sulfate).

Which of the following ions is a polyatomic ion?

• S²⁻

• ClO₂⁻

• Na⁺

• Cl⁻

Answer explanation

The correct choice is ClO₂⁻, which is a polyatomic ion consisting of multiple atoms (chlorine and oxygen). In contrast, S²⁻, Na⁺, and Cl⁻ are all monatomic ions, made up of single atoms.

What is the name of the polyatomic ion with the formula PO₄³⁻?

• Phosphate

• Phosphite

• Phosphide

• Phosphine

Answer explanation

The ion with the formula PO₄³⁻ is called phosphate. It consists of one phosphorus atom and four oxygen atoms, carrying a -3 charge. Other options like phosphite and phosphide refer to different chemical species.

What is the name of the polyatomic ion with the formula NO₂⁻?

• Nitrate

• Nitrite

• Nitride

• Nitronium

Answer explanation

The ion with the formula NO₂⁻ is called nitrite. Nitrate has the formula NO₃⁻, nitride refers to N³⁻, and nitronium is a cation (NO₂⁺). Therefore, the correct answer is nitrite.

What is the chemical formula for nitrite?

• NO₂⁻

• NO₃⁻

• NO⁻

• NO₄⁻

Answer explanation

The chemical formula for nitrite is NO₂⁻, which indicates it has one nitrogen atom and two oxygen atoms with a negative charge. The other options represent different ions: NO₃⁻ is nitrate, NO⁻ is nitroxyl, and NO₄⁻ is not a common ion.

According to VSEPR theory, what determines the shape of a molecule?

• The number of atoms in the molecule

• The repulsion between valence electron pairs

• The type of chemical bonds

• The molecular weight

Answer explanation

According to VSEPR theory, the shape of a molecule is determined by the repulsion between valence electron pairs. This repulsion affects the arrangement of atoms, leading to specific molecular geometries.

What type of bond involves electrons that are not shared equally, causing a partial charge?

• Nonpolar covalent bond

• Ionic bond

• Polar covalent bond

• Metallic bond

Answer explanation

A polar covalent bond occurs when electrons are shared unequally between atoms, leading to a partial positive charge on one atom and a partial negative charge on the other, unlike nonpolar covalent bonds where electrons are shared equally.

What is the result of equal sharing of electrons in a bond?

• Development of a partial charge

• Development of a net charge

• Cancellation of any charge, making it neutral

• Increase in electronegativity

Answer explanation

Equal sharing of electrons in a bond leads to a balanced distribution of charge, resulting in no overall charge. This is why the correct answer is 'Cancellation of any charge, making it neutral'.

What is the chemical formula for carbonate?

• CO₂

• CH₄

• HCO₃⁻

• CO₃²⁻