Question

1. classify the following as pure substances or as mixtures: air, gasoline, grain alcohol, water, sugar, gold, mercury, oxygen, salt water. 14. classify the following as heterogeneous or as homogeneous: sand & salt mixture, hydrogen, iron, salt water, unfiltered air, iron with rust, pure water, an apple, nitric acid, tossed salad, granite, wood. 15. classify the following as an element, a compound, a solution, or a heterogeneous mixture: aluminum, raisin bread, carbon dioxide, water, sugar and water, sulfur, sulfuric acid, mercury, an orange, water & instant coffee, a pencil, carbon particles & sugar, nitrogen, air, gasoline, grain alcohol

Explanation:

Step1: Recall definitions

Pure substances have a fixed - composition, while mixtures are composed of two or more substances. Homogeneous mixtures have uniform composition and properties, and heterogeneous mixtures have non - uniform composition. Elements are made of one type of atom, compounds are made of two or more different types of atoms chemically combined, and solutions are homogeneous mixtures.

Step2: Classify as pure substances or mixtures (Question 13)

• Air: Mixture (contains nitrogen, oxygen, etc.).
• Gasoline: Mixture (a blend of hydrocarbons).
• Grain alcohol: Pure substance (ethanol, a compound).
• Water: Pure substance (a compound).
• Sugar: Pure substance (a compound).
• Gold: Pure substance (an element).
• Mercury: Pure substance (an element).
• Oxygen: Pure substance (an element).
• Salt water: Mixture (sodium chloride dissolved in water).

Step3: Classify as heterogeneous or homogeneous (Question 14)

• Sand & salt mixture: Heterogeneous (visible different components).
• Hydrogen: Homogeneous (an element, pure substance).
• Iron: Homogeneous (an element, pure substance).
• Salt water: Homogeneous (a solution).
• Unfiltered air: Homogeneous (a mixture with uniform composition).
• Iron with rust: Heterogeneous (rust is a different compound on iron).
• Pure water: Homogeneous (a compound).
• An apple: Heterogeneous (contains different parts like skin, pulp).
• Nitric acid: Homogeneous (a compound).
• Tossed salad: Heterogeneous (different vegetables).
• Granite: Heterogeneous (contains different minerals).
• Wood: Heterogeneous (contains different organic materials).

Step4: Classify as element, compound, solution, or heterogeneous mixture (Question 15)

• Aluminum: Element.
• Raisin bread: Heterogeneous mixture.
• Carbon dioxide: Compound.
• Water: Compound.
• Sugar and water: Solution.
• Sulfur: Element.
• Sulfuric acid: Compound.
• Mercury: Element.
• An orange: Heterogeneous mixture.
• Water & instant coffee: Solution.
• A pencil: Heterogeneous mixture.
• Carbon particles & sugar: Heterogeneous mixture.
• Nitrogen: Element.
• Air: Solution (a homogeneous mixture of gases).
• Gasoline: Solution (a homogeneous mixture of hydrocarbons).
• Grain alcohol: Compound.

Answer:

13.

• Air: Mixture
• Gasoline: Mixture
• Grain alcohol: Pure substance
• Water: Pure substance
• Sugar: Pure substance
• Gold: Pure substance
• Mercury: Pure substance
• Oxygen: Pure substance
• Salt water: Mixture

14.

• Sand & salt mixture: Heterogeneous
• Hydrogen: Homogeneous
• Iron: Homogeneous
• Salt water: Homogeneous
• Unfiltered air: Homogeneous
• Iron with rust: Heterogeneous
• Pure water: Homogeneous
• An apple: Heterogeneous
• Nitric acid: Homogeneous
• Tossed salad: Heterogeneous
• Granite: Heterogeneous
• Wood: Heterogeneous

15.

• Aluminum: Element
• Raisin bread: Heterogeneous mixture
• Carbon dioxide: Compound
• Water: Compound
• Sugar and water: Solution
• Sulfur: Element
• Sulfuric acid: Compound
• Mercury: Element
• An orange: Heterogeneous mixture
• Water & instant coffee: Solution
• A pencil: Heterogeneous mixture
• Carbon particles & sugar: Heterogeneous mixture
• Nitrogen: Element
• Air: Solution
• Gasoline: Solution
• Grain alcohol: Compound