Real-world examples of pure substances vs. mixtures in daily life

🧪 Quick Study Guide

• 🧱 Pure Substance: A substance with a fixed chemical composition and distinct properties. Examples include elements (like gold, $Au$) and compounds (like water, $H_2O$).
• 💧 Mixture: A combination of two or more substances that are physically combined. The components retain their individual identities and can be separated by physical means.
• 🌈 Homogeneous Mixture: A mixture with uniform composition throughout. You can't see the different parts. Example: Saltwater.
• 🌫️ Heterogeneous Mixture: A mixture with non-uniform composition. You *can* see the different parts. Example: Salad.
• 🧲 Separation Techniques: Mixtures can be separated using techniques like filtration, evaporation, distillation, and magnetism.

✍️ Practice Quiz

1. Which of the following is an example of a pure substance?
   1. A. Air
   2. B. Seawater
   3. C. Gold
   4. D. Orange juice
2. Which of the following is a homogeneous mixture?
   1. A. Pizza
   2. B. Salad
   3. C. Sugar dissolved in water
   4. D. Gravel
3. Which of the following is an example of a heterogeneous mixture?
   1. A. Vinegar
   2. B. Blood
   3. C. Carbon Dioxide
   4. D. Vegetable soup
4. Which method would be best to separate salt from saltwater?
   1. A. Filtration
   2. B. Distillation
   3. C. Magnetism
   4. D. Chromatography
5. Which of these is a compound?
   1. A. Helium
   2. B. Diamond
   3. C. Water
   4. D. Iron
6. What type of mixture is concrete?
   1. A. Homogeneous
   2. B. Heterogeneous
   3. C. Pure substance
   4. D. Element
7. Which of the following is an element?
   1. A. Baking soda ($NaHCO_3$)
   2. B. Salt ($NaCl$)
   3. C. Oxygen ($O_2$)
   4. D. Sugar ($C_{12}H_{22}O_{11}$)