Grade 10 Science Exam Notes - Chemistry - PDF

Science Exam Notes Grade 10 Science Exam Review Grade 10 Exam Review with Full Definitions CHEMISTRY: Chemical Reactions Key Topics to Review: 1.​ Matter ​ Definition: Matter is anything that has mass and occupies space. It exists in different states, including solid, liq...

Science Exam Notes Grade 10 Science Exam Review Grade 10 Exam Review with Full Definitions CHEMISTRY: Chemical Reactions Key Topics to Review: 1.​ Matter ​ Definition: Matter is anything that has mass and occupies space. It exists in different states, including solid, liquid, and gas. ​ Classification: ​ Pure Substances: Consist of only one type of atom or molecule. Examples include elements (e.g., gold, oxygen) and compounds (e.g., water, sodium chloride). ​ Mixtures: Combinations of two or more substances that retain their individual properties. They can be: ​ Homogeneous Mixtures: The composition is uniform throughout (e.g., air, saltwater). ​ Heterogeneous Mixtures: The composition is not uniform, and the individual components can be seen (e.g., salad, granite). ​ Physical Changes: Changes that affect the form of a substance but not its chemical composition (e.g., melting ice, tearing paper). ​ Chemical Changes: Changes that result in the formation of new substances with different chemical properties (e.g., burning wood, rusting of iron). Indicators include color change, gas formation, and temperature change. 2.​ Lewis Structure Diagrams ​ Definition: Lewis structures are diagrams that represent the bonding between atoms and the lone pairs of electrons in a molecule. They show the valence electrons (electrons in the outermost shell) of atoms. ​ Atoms: Basic units of matter consisting of protons, neutrons, and electrons. For example, a hydrogen atom (H) has one proton and one electron. ​ Ions: Atoms that have gained or lost electrons, thus acquiring a charge. For example, a chloride ion (Cl⁻) has gained one electron to achieve a full outer shell, giving it a negative charge. 3.​ Compounds ​ Ionic Compounds: Formed when electrons are transferred from one atom (typically a metal) to another (typically a nonmetal). This results in positively charged ions (cations) and negatively charged ions (anions) that are held together by electrostatic forces. For example, sodium chloride (NaCl) is formed by the transfer of an electron from sodium (Na) to chlorine (Cl). ​ Monovalent Metals: Metals that form ions with a single positive charge. Example: Sodium (Na⁺), Potassium (K⁺). ​ Bivalent Metals: Metals that form ions with a double positive charge. Example: Calcium (Ca²⁺), Iron (Fe²⁺ or Fe³⁺).  ​ Polyatomic Compounds: Compounds consisting of multiple atoms bonded together that carry a charge. An example is the nitrate ion (NO₃⁻), where nitrogen and oxygen are bonded together and carry a negative charge. ​ Molecular Compounds: Compounds made up of two or more nonmetals that share electrons to form covalent bonds. For example, carbon dioxide (CO₂) is a molecular compound where carbon shares electrons with oxygen. ​ Acids: Compounds that release hydrogen ions (H⁺) when dissolved in water. For example, hydrochloric acid (HCl) releases H⁺ ions when dissolved in water. ​ Bases: Compounds that release hydroxide ions (OH⁻) when dissolved in water. An example is sodium hydroxide (NaOH), which dissociates into Na⁺ and OH⁻ ions in water. 4.​ Balancing Equations ​ Definition: Balancing chemical equations involves adjusting the coefficients of reactants and products so that the number of atoms of each element is the same on both sides of the equation, in accordance with the Law of Conservation of Mass. ​ Example: ​ Unbalanced: H₂ + O₂ → H₂O ​ Balanced: 2H₂ + O₂ → 2H₂O 5.​ Types of Reactions ​ Synthesis (Combination) Reaction: Two or more substances combine to form a single product. Example:​ A+ B →AB​ ​ Decomposition Reaction: A single compound breaks down into two or more simpler substances. Example:​ AB → A + B ​ ​ Single Displacement (Replacement) Reaction: One element replaces another in a compound. Example:​ A + BC → B + AC​ ​ Double Displacement (Replacement) Reaction: Two compounds exchange ions to form two new compounds. Example:​ AB + CD → AD + CB ​ ​ Neutralization Reaction: An acid reacts with a base to produce a salt and water. Example:​ ​ HCl+NaOH→NaCl+H2 O 6.​ Acids and Bases ​ Acids: Substances that increase the concentration of hydrogen ions (H⁺) in an aqueous solution. They generally have a sour taste (e.g., vinegar) and turn blue litmus paper red. ​ Bases: Substances that increase the concentration of hydroxide ions (OH⁻) in an aqueous solution. They feel slippery and turn red litmus paper blue. An example is sodium hydroxide (NaOH). Practice: ​ Write and balance equations. ​ Complete Self Quizzes: Pages 218-219, 260-261, 296-297. BIOLOGY: Tissues, Organs, and Systems of Living Things Key Topics to Review: 1.​ Cell Parts & Functions ​ Cell Membrane: The thin, flexible outer layer of the cell that controls the movement of substances in and out of the cell. It is selectively permeable. ​ Nucleus: The control center of the cell that contains the cell's DNA. It regulates gene expression and cell division. ​ Mitochondria: Organelles that produce energy for the cell through cellular respiration. They convert glucose and oxygen into ATP (adenosine triphosphate), the energy currency of the cell. ​ Chloroplasts: Found in plant cells, chloroplasts contain chlorophyll and are responsible for photosynthesis, the process by which plants convert sunlight into chemical energy (glucose). 2.​ Organ Systems ​ Circulatory System: Consists of the heart, blood vessels, and blood. It is responsible for transporting oxygen, nutrients, hormones, and waste products throughout the body. ​ Digestive System: A group of organs that break down food into nutrients, which the body uses for energy, growth, and repair. Key organs include the stomach, small intestine, and liver. ​ Respiratory System: The system responsible for taking in oxygen and expelling carbon dioxide. Key organs include the lungs, trachea, and diaphragm. 3.​ Blood Composition ​ Red Blood Cells (RBCs): Cells that carry oxygen from the lungs to the body and return carbon dioxide to the lungs to be exhaled. They contain hemoglobin, a protein that binds to oxygen. ​ White Blood Cells (WBCs): Cells that are part of the immune system. They fight infections by attacking pathogens like bacteria and viruses. ​ Platelets: Small cell fragments that help with blood clotting. They prevent excessive bleeding when injuries occur. 4.​ Cell Cycle ​ Interphase: The phase of the cell cycle where the cell grows, performs its normal functions, and prepares for cell division. During this phase, DNA is replicated. ​ Mitosis: The process of cell division that results in two genetically identical daughter cells. It occurs in several stages: Prophase, Metaphase, Anaphase, and Telophase. ​ Cytokinesis: The final stage of cell division where the cytoplasm is divided between the two daughter cells, completing cell division. 5.​ Cancer ​ Definition: Cancer is the uncontrolled growth and division of abnormal cells. Cancer cells bypass the normal mechanisms that regulate cell growth and death, leading to tumor formation and metastasis (spread to other parts of the body). ​ Causes: Genetic mutations, exposure to carcinogens (such as tobacco smoke), radiation, and certain viral infections.  ​ Treatments: Common treatments include surgery (to remove tumors), chemotherapy (using drugs to kill cancer cells), and radiation therapy (using high-energy radiation to destroy cancer cells). 6.​ Specialized Cells & Stem Cells ​ Specialized Cells: Cells that have developed specific structures and functions suited to their roles. Examples include muscle cells (contract to generate movement) and nerve cells (transmit electrical signals). ​ Stem Cells: Undifferentiated cells that have the potential to develop into any type of specialized cell. They play a crucial role in growth, repair, and regeneration. 7.​ Organ Transplantation ​ Definition: The surgical process of transferring a healthy organ from a donor to a recipient whose organ is diseased or damaged. Examples include heart, kidney, and liver transplants. ​ Challenges: Issues such as organ rejection (where the recipient's immune system attacks the transplanted organ) and organ shortages. 8.​ Microscope Calculations ​ Magnification: The process of enlarging the appearance of an object. The total magnification of a microscope is calculated by multiplying the magnification of the ocular lens by the magnification of the objective lens. ​ Formula:​ Total Magnification​ =​ Ocular Lens Magnification​ ×​ Objective Lens Magnification​ ​ ​ Total Magnification=Ocular Lens Magnification×Objective Lens Magnification