student examples of informative essays grade 8

🧪 Quick Study Guide

• ⚛️ Atoms: The basic building blocks of matter. Remember they're made of protons, neutrons, and electrons.
• 🧪 Elements: Pure substances made of only one type of atom (e.g., Hydrogen (H), Oxygen (O)). Find them all on the periodic table!
• 🤝 Compounds: Substances formed when two or more elements are chemically bonded together (e.g., Water ($H_2O$), Carbon Dioxide ($CO_2$)).
• ➕ Mixtures: Combinations of substances that are physically mixed but not chemically bonded (e.g., Saltwater, Air).
• 🧮 Chemical Equations: Symbolic representations of chemical reactions using symbols and formulas (e.g., $2H_2 + O_2 \rightarrow 2H_2O$). Make sure they're balanced!
• ⚖️ Balancing Equations: Ensuring the number of atoms for each element is the same on both sides of the equation. This follows the Law of Conservation of Mass.
• 🌡️ States of Matter: Solid, liquid, gas, and plasma. Each has different properties based on how the molecules are arranged and move.

Practice Quiz

1. Which of the following is an example of an element?
   1. A. Water ($H_2O$)
   2. B. Salt (NaCl)
   3. C. Oxygen ($O_2$)
   4. D. Carbon Dioxide ($CO_2$)
2. What is a compound?
   1. A. A substance made of only one type of atom.
   2. B. A combination of substances physically mixed.
   3. C. A substance formed when two or more elements are chemically bonded.
   4. D. Any substance that can be found on the periodic table.
3. Which of the following is a balanced chemical equation?
   1. A. $H_2 + O_2 \rightarrow H_2O$
   2. B. $2H_2 + O_2 \rightarrow H_2O$
   3. C. $H_2 + O_2 \rightarrow 2H_2O$
   4. D. $2H_2 + O_2 \rightarrow 2H_2O$
4. What does it mean to balance a chemical equation?
   1. A. To make sure the equation looks aesthetically pleasing.
   2. B. To ensure the number of atoms for each element is the same on both sides of the equation.
   3. C. To add more elements to the equation.
   4. D. To remove unnecessary compounds from the equation.
5. Which of the following is an example of a mixture?
   1. A. Water ($H_2O$)
   2. B. Salt (NaCl)
   3. C. Air
   4. D. Methane ($CH_4$)
6. Which state of matter has a definite volume but not a definite shape?
   1. A. Solid
   2. B. Liquid
   3. C. Gas
   4. D. Plasma
7. What are the three subatomic particles that make up an atom?
   1. A. Molecules, Compounds, and Elements
   2. B. Protons, Neutrons, and Electrons
   3. C. Solids, Liquids, and Gases
   4. D. Mixtures, Solutions, and Suspensions