Pure substance vs. Mixture
A sample of iron (Fe) contains only iron atoms. Is it a pure substance or a mixture?
Pure Substance
Classify oxygen, O₂.
Element
Convert 3.5 L to mL.
3,500 mL
Convert 60 inches to feet.
Use: 12 in = 1 ft
5 ft
A bowl of cereal with milk contains compounds such as lactose (C₁₂H₂₂O₁₁) in the milk and starch (C6H10O5)n(C₆H₁₀O₅)_n in the cereal. The cereal pieces remain visibly separate from the milk.
Is this mixture homogeneous or heterogeneous?
Heterogeneous
Air contains several gases mixed together. Is air a pure substance or a mixture?
Mixture
Classify carbon dioxide, CO₂.
Compound
Convert 2,400 m to km.
2.4 km
Convert 4.5 feet to inches.
Use: 12 in = 1 ft
54 in
Mouthwash contains water (H₂O) along with dissolved compounds such as ethanol (C₂H₆O) and flavoring compounds. If you shine a light through it, you can just barely see a beam.
Is mouthwash homogeneous or heterogeneous?
Homogeneous
Pure water, H₂O, contains only water molecules. Is it a pure substance or a mixture?
Pure Substance
Salt is completely dissolved in water so the mixture looks the same throughout. Classify the mixture.
Homogeneous mixture
Convert 0.725 kg to g.
725 g
Convert 0.50 L to mL using dimensional analysis.
500 mL
Rubbing alcohol contains compounds such as isopropyl alcohol (C₃H₈O) and water (H₂O). The compounds are mixed at a microscopic level.
Is rubbing alcohol homogeneous or heterogeneous?
Homogenous
Soil contains different minerals, organic material, and other substances. Is soil a pure substance or a mixture?
Mixture
A bowl of trail mix contains visibly different ingredients. Classify the mixture.
Heterogeneous mixture
Convert 45.2 cm to m.
0.452 m
A student has 2.50 kg of a substance. How many milligrams (mm) is this?
2,500,000 mg
Butter contains tiny droplets of water (H2O) dispersed throughout fat. You cannot see these different parts with your eyes. If you mix butter into water and shine light through it, you can clearly see the beam.
Based on its particle-level composition, is it homogeneous or heterogeneous?
Heterogeneous
A material can be physically separated into two different substances. Based on this information, is it most likely a pure substance or a mixture?
Mixture
A substance contains two different elements chemically bonded together in a fixed ratio. Is it an element, compound, homogeneous mixture, or heterogeneous mixture?
Compound
Convert 0.0084 km to mm.
8,400 mm
Convert 72 km/h to m/s.
Use: 1 km = 1000 m, 1 hr = 3600 s
20 m/s
Nichrome is a solid material made by evenly mixing metals such as nickel (Ni) and chromium (Cr). The particles are mixed microscopically (you cannot see its different parts). The metal looks shiny though: you think that if you dissolve small pieces of it in water and shine a light on it, you might see the beam. You don't have time to test it though...
Is nichrome a homogeneous or heterogeneous mixture?
Homogeneous mixture