Question

classify each of the materials below. in the center column, state whether the material is a pure substance or a mixture. if the material is a pure substance, further classify it as either an element or compound in the right column. similarly, if the material is a mixture, further classify it as homogeneous or heterogeneous in the right column. write the entire word in each space to earn full credit.

Explanation:

• Concrete: A mixture of cement, water, sand, and gravel. The components are not uniformly distributed, so it is a heterogeneous mixture.
• Sugar + pure water ($C_{12}H_{22}O_{11}+H_2O$): A solution where sugar dissolves in water. The composition is uniform throughout, so it is a homogeneous mixture.
• Iron filings ($Fe$): Made up of only iron atoms. It is a pure substance and an element.
• Limestone ($CaCO_3$): A pure substance. It is a compound as it is made of calcium, carbon, and oxygen chemically combined.
• Orange juice (w/pulp): Pulp is not uniformly distributed in the juice. So it is a heterogeneous mixture.
• Pacific Ocean: Contains water, salts, dissolved gases, etc. The composition is not uniform (e.g., near - shore vs. deep - sea has different compositions). It is a heterogeneous mixture.
• Air inside a balloon: A mixture of gases like nitrogen, oxygen, carbon dioxide, etc. The composition is uniform at the molecular level (assuming no stratification), so it is a homogeneous mixture.
• Aluminum ($Al$): Composed of only aluminum atoms. It is a pure substance and an element.
• Magnesium ($Mg$): Composed of only magnesium atoms. It is a pure substance and an element.
• Acetylene ($C_2H_2$): A pure substance. It is a compound as it is made of carbon and hydrogen chemically combined.
• Tap water in a glass: Contains water, dissolved minerals, etc. The composition is uniform (assuming no sediment), so it is a homogeneous mixture.
• Soil: Contains minerals, organic matter, water, air. The components are not uniformly distributed. It is a heterogeneous mixture.
• Pure water ($H_2O$): A pure substance. It is a compound as it is made of hydrogen and oxygen chemically combined.
• Chromium ($Cr$): Composed of only chromium atoms. It is a pure substance and an element.
• Chex mix: A mixture of different snacks (e.g., cereal pieces, pretzels). The components are not uniformly distributed. It is a heterogeneous mixture.
• Salt + pure water ($NaCl + H_2O$): A solution where salt dissolves in water. The composition is uniform, so it is a homogeneous mixture.
• Benzene ($C_6H_6$): A pure substance. It is a compound as it is made of carbon and hydrogen chemically combined.
• Muddy water: Mud particles are not uniformly distributed in water. It is a heterogeneous mixture.
• Brass ($Cu$ mixed with $Zn$): A solid solution (alloy). The composition is uniform at the atomic level, so it is a homogeneous mixture.
• Baking soda ($NaHCO_3$): A pure substance. It is a compound as it is made of sodium, hydrogen, carbon, and oxygen chemically combined.

Answer:

Material	Pure Substance or Mixture	Element, Compound, Homogeneous, Heterogeneous
sugar + pure water ($C_{12}H_{22}O_{11}+H_2O$)	Mixture	Homogeneous
iron filings ($Fe$)	Pure Substance	Element
limestone ($CaCO_3$)	Pure Substance	Compound
orange juice (w/pulp)	Mixture	Heterogeneous
Pacific Ocean	Mixture	Heterogeneous
air inside a balloon	Mixture	Homogeneous
aluminum ($Al$)	Pure Substance	Element
magnesium ($Mg$)	Pure Substance	Element
acetylene ($C_2H_2$)	Pure Substance	Compound
tap water in a glass	Mixture	Homogeneous
soil	Mixture	Heterogeneous
pure water ($H_2O$)	Pure Substance	Compound
chromium ($Cr$)	Pure Substance	Element
Chex mix	Mixture	Heterogeneous
salt + pure water ($NaCl + H_2O$)	Mixture	Homogeneous
benzene ($C_6H_6$)	Pure Substance	Compound
muddy water	Mixture	Heterogeneous
brass ($Cu$ mixed with $Zn$)	Mixture	Homogeneous
baking soda ($NaHCO_3$)	Pure Substance	Compound