Quizziz Hydrocarbons

Maya is studying organic chemistry and wants to know the general formula for alkanes. Can you help her?

• CnH(2n+2)

• C(n-1)H(2n-2)

• CnH2n

• C2nH2n

Answer explanation

The general formula for alkanes is CnH(2n+2), where n represents the number of carbon atoms. This formula accounts for the maximum number of hydrogen atoms that can bond with the carbon atoms in a saturated hydrocarbon.

Name the first three alkanes in the homologous series.

• Methane, Ethane, Propane

• Methanol, Ethanol, Propanol

• Butane, Pentane, Hexane

• Acetylene, Benzene, Toluene

Answer explanation

The first three alkanes in the homologous series are methane (C1), ethane (C2), and propane (C3). They are saturated hydrocarbons with single bonds, distinguishing them from other options like alcohols and aromatic compounds.

Nita is studying organic chemistry and wants to understand the differences between alkanes and alkenes. What is the main difference between these two types of hydrocarbons?

• Alkenes have a higher molecular weight than alkanes.

• Alkanes contain double bonds, while alkenes contain only single bonds.

• Alkanes are more reactive than alkenes due to their structure.

• The main difference is that alkanes have only single bonds, whereas alkenes have at least one double bond.

Answer explanation

The main difference is that alkanes have only single bonds, whereas alkenes have at least one double bond. This structural distinction leads to different chemical properties and reactivities between the two types of hydrocarbons.

Provide an example of a reaction that alkenes undergo.

• Cyclohexene + O2 → Cyclohexanol

• Ethene + Br2 → 1,2-dibromoethane

• Butene + H2O → Butanol

• Propene + H2 → Propune

Answer explanation

The reaction of ethene with Br2 to form 1,2-dibromoethane is a classic example of an electrophilic addition reaction, where the double bond in the alkene reacts with bromine, resulting in the addition of bromine atoms across the double bond.

Rizal is studying the structure of cycloalkanes in his chemistry class. What is the structure of cycloalkanes?

• Cycloalkanes are linear chains of carbon atoms.

• Cycloalkanes consist of only one carbon atom in a straight line.

• Cycloalkanes have a ring structure of carbon atoms, with the general formula CnH2n.

• Cycloalkanes have a branched structure with the formula CnH2n+2.

Answer explanation

Cycloalkanes are characterized by a ring structure of carbon atoms, which distinguishes them from linear or branched alkanes. Their general formula is CnH2n, indicating the relationship between carbon and hydrogen atoms.

How do cycloalkanes differ from linear alkanes?

• Cycloalkanes contain more carbon atoms than linear alkanes.

• Cycloalkanes are more stable than linear alkanes.

• Cycloalkanes have a ring structure, whereas linear alkanes have a straight chain structure.

• Linear alkanes have a branched structure, while cycloalkanes do not.

Answer explanation

Cycloalkanes differ from linear alkanes in that cycloalkanes have a ring structure, while linear alkanes consist of a straight chain of carbon atoms. This structural difference is key to their classification.

Define aromatic hydrocarbons and give an example.

• naphtalene

• hexane

• Propylene

• Ethylene

Answer explanation

Aromatic hydrocarbons are compounds that contain one or more benzene rings. Naphtalene is an example, consisting of two fused benzene rings, while hexane, propylene, and ethylene are not aromatic compounds.

Agus is studying the process of hydrogen addition in hydrocarbons for his chemistry class.

• Hydrogen addition involves the addition of oxygen to hydrocarbons.

• Hydrogen addition is the process of breaking down hydrocarbons into smaller molecules.

• Hydrogen addition is the addition of hydrogen to unsaturated hydrocarbons, converting them into saturated hydrocarbons.

• Hydrogen addition removes hydrogen from saturated hydrocarbons.

Answer explanation

Hydrogen addition specifically refers to adding hydrogen to unsaturated hydrocarbons, which transforms them into saturated hydrocarbons. This process is essential in organic chemistry for modifying hydrocarbon structures.

During a chemistry class, Angga asked, "What are the physical properties of alkanes?"

• Alkanes are colorless, odorless, low-density gases or liquids, low solubility in water, and have increasing boiling/melting points with molecular weight.

• Alkanes are highly soluble in water and have low boiling points.

• Alkanes are dense solids with decreasing melting points as molecular weight increases.

• Alkanes are brightly colored and have a strong odor.

Answer explanation

The correct choice accurately describes alkanes as colorless, odorless, low-density gases or liquids, with low water solubility and increasing boiling/melting points as molecular weight rises, which aligns with their known physical properties.

Explain the concept of isomerism in hydrocarbons.

• Isomerism in hydrocarbons is the variation in molecular weight among different compounds.

• Isomerism is the process of breaking down hydrocarbons into simpler compounds.

• Isomerism in hydrocarbons is the existence of compounds with the same molecular formula but different structures or arrangements.

• Isomerism refers to the ability of hydrocarbons to form multiple bonds.

Answer explanation

Isomerism in hydrocarbons refers to compounds that share the same molecular formula but differ in their structural arrangement. This leads to various physical and chemical properties, making it a key concept in organic chemistry.