Study Guide

Write the chemical formula for calcium chloride.

• CaCl₂

• CaCl

• Ca₂Cl

• CaCl₃

Answer explanation

The correct chemical formula for calcium chloride is CaCl2. This indicates one calcium (Ca) atom and two chloride (Cl) atoms, which is necessary to balance the charges, as calcium has a +2 charge and chloride has a -1 charge.

Tags

NGSS.MS-PS1-1

Name the compound FeCl₃.

• Iron (III) chloride

• Iron (II) chloride

• Ferric oxide

• Ferrous chloride

Answer explanation

FeCl3 is named Iron (III) chloride because the iron has a +3 oxidation state, indicated by the Roman numeral III. This distinguishes it from Iron (II) chloride (FeCl2), which has a +2 oxidation state.

Write the formula for aluminium sulfate.

• Al₂(SO₄)₃

• Al₂SO₄

• Al(SO₄)₂

• AlSO₄

Answer explanation

The formula for aluminum sulfate is Al2(SO4)3. This indicates that there are 2 aluminum (Al) ions and 3 sulfate (SO4) groups, which is the correct representation of the compound.

Tags

NGSS.MS-PS1-1

Name the compound Pb(NO₃)₂.

• Lead (II) nitrate

• Lead (IV) nitrate

• Lead (II) nitrite

• Lead (IV) nitrite

Answer explanation

The compound Pb(NO3)2 contains lead in the +2 oxidation state, indicated by the Roman numeral II. Therefore, it is named Lead (II) nitrate, distinguishing it from Lead (IV) nitrate, which would have a different formula.

Write the formula for sodium phosphate.

• Na₃PO₄

• Na₂PO₄

• NaPO₄

• Na₃PO₃

• Na₂SO₄

Answer explanation

The formula for sodium phosphate is Na3PO4, which indicates three sodium (Na) ions and one phosphate (PO4) ion. The other options either have incorrect ratios or represent different compounds.

Name the acid HNO₃.

• Nitric acid

• Sulfuric acid

• Hydrochloric acid

• Acetic acid

Answer explanation

HNO3 is commonly known as nitric acid. It is a strong acid used in various applications, including fertilizers and explosives. The other options listed are different acids with distinct chemical formulas.

Write the formula for copper(II) sulfate.

• CuSO₄

• Cu₂SO₄

• CuSO₃

• Cu₂(SO₄)₃

Answer explanation

Copper (II) sulfate is represented by the formula CuSO4, indicating one copper ion (Cu^2+) and one sulfate ion (SO4^2-). The other options either represent incorrect formulas or different compounds.

Name the acid HClO₃.

• Chloric acid

• Chlorous acid

• Hypochlorous acid

• Perchloric acid

Answer explanation

HClO3 is known as chloric acid. It is a strong acid derived from chlorine, and its name reflects the oxidation state of chlorine in the compound. The other options refer to different acids with varying oxidation states.

Write the formula for potassium permanganate.

• KMnO₄

• K₂MnO₄

• KClO₄

• K₂MnO₃

Answer explanation

The formula for potassium permanganate is KMnO4, which consists of one potassium (K), one manganese (Mn), and four oxygen (O) atoms. The other options do not represent potassium permanganate.

Tags

NGSS.MS-PS1-1

Name the compound Cu₂O.

• Copper (I) oxide

• Copper (II) oxide

• Copper peroxide

• Copper hydroxide

Answer explanation

Cu2O contains copper in the +1 oxidation state, hence it is named Copper (I) oxide. The other options refer to different oxidation states or compounds of copper.

Tags

NGSS.MS-PS1-1