Science 7 Midterm Lecture PDF 2024-2025

SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY Prepared by: Ashleigh Reese Lemsic (7 - Nepal) an acid reacts with a “matrix.” and forms a...

SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY Prepared by: Ashleigh Reese Lemsic (7 - Nepal) an acid reacts with a “matrix.” and forms a salt. Study Buddy: Sofia Nicole Tolentino (7 - Nepal) Neutralization: Examiner’s Mandates When an acid mixes with a base, water 1. Lesson I: Nature of Silutins (Acids, and salt are produced. Such a process Bases, and Salts) is called neutralization. 2. Lesson II: Types of Solutions Solutions that are not acidic or basic 3. Lesson III: Factors that affect are called neutral solutions. Solubility 4. Lesson IV: Concentrations of Solutions The process of Neutralization has some uses in Everyday Life: Treating insect stings. Treating indigestion. Nature of Solutions Using toothpaste to avoid tooth decay. (Acids, Bases, and Salts) Treating soil Treating factory waste. Acids Bases · pH less than 7 · pH greater than 7 While pure water has a neutral pH of 7, it is also · turns blue litmus paper red · turn red litmus paper blue both a weak acid and a weak base. The reason · taste sour · taste bitter or soapy is because some water (H2O) molecules break · sting or just feel wet · feel slippery into H+ and OH- ions. · react with some metals to · include baking soda, give off hydrogen gas ammonia, and soap To neutralize a dangerous acid use baking soda · conduct electricity in · dissolve fats and oils or another weak base. solution Neutralize a strong base (like drain cleaner), · examples are fruit juices, with vinegar before cleaning it up. soda, and coffee The pH scale measures the acidity or alkalinity of a solution, ranging from 0 (very acidic) to 14 (very alkaline), with 7 being neutral (pure water). Acids have pH values less than 7, bases have pH values greater than 7, and neutral substances Acids and Bases: have a pH of 7. The word “acid” comes from the Latin word “acere”, which means sour. The word “base” comes from an alchemy concept of a “ matrix”. Alchemists realized SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25  SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY Uses of Acids Carbonic acid – aerated drinks Sulphuric acid – car batteries and paint Tartaric acid – wine manufacturing Nitric acid – fertilizers Hydrochloric acid – digestion Salicylic acid – aspirin Acetic acid – vinegar Citric acid – citrus fruits Acid used in – labs SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25  SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY 2. Unsaturated solution contains less solute than a saturated solution. Safe Handling Procedures Clean containers after use with deionized 3. Supersaturated solution is a solution water. whose concentration exceeds the Work under a fume hood unless you have been saturation point of the solution at a told otherwise by your teacher. Use a funnel when pouring chemicals into a certain temperature. small container. Open bottles slowly to avoid spilling and allow vapors to escape. Know what type of reactions to expect. Remember to triple-A (AAA): Always Add Acid to water. First Aid If an acid or base gets on your skin or in your eyes, you should rinse the area with water. If it is a strong acid or base keep rinsing the area for 5-15 minutes. If an acid or base gets on your clothing you should quickly and carefully remove the A Solution is a homogeneous mixture of clothing—it is protecting you now, but chemicals two or more substances. can soak through and will be hard to wash away. Many laboratories will have a safety shower The two main components of a solution to allow large spills to be washed away are the solute and the solvent. without spreading the chemicals. 2. Types of Solutions based on the Physical State of Solute and Solvent: TYPE OF SOLUTION The Solute is the substance or component that is being dissolved in the solvent. It can be a solid, 1. Types of Solutions based on the degree liquid, or gas. of Saturation: The Solvent is the substance that dissolves the solute. 1. Saturated solution contains as much The solute and solvent do not need solute as can be dissolved at a given to be in the same physical state, temperature. the solvent's state typically dictates the solution's state. SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25  SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY A solute is considered to be soluble They tend to settle over time, in a solvent if it mixes with the meaning the solid particles will solvent to form a homogeneous eventually fall out of the liquid. solution. The solute is lesser in quantity than Examples of suspensions: the solvent. Muddy water, soft drinks, fruit Here are the examples : drinks, coffee creamers, etc. FACTORS THAT AFFECT SOLUBILITY Solubility – the maximum amount of solute that can be dissolved in a given amount of solvent at a specified temperature. If liquids can mix and form a solution, they are described as miscible, while they are described as immiscible if they cannot mix homogeneously. COLLOIDS - a mixture where tiny particles Example : of one substance are evenly spread Ethyl alcohol and water are miscible in throughout another substance. each other in all proportions. Oil and water are immiscible Tyndall Effect - Colloids scatter light, because they form two layers when causing the beam to be visible. This is mixed; thus, they are said to form a how you can see a beam of light heterogeneous mixture. passing through fog or a dusty room. Examples of colloids: 1. Nature of Solute and Solvent Foam, Milk, Smoke, Detergents, “Like dissolves like” : Substances with Gel, Blood, Paint, Cosmetics, similarity in polarity of the solute and Gelatin, etc. solvent particles, a property attributed to having positive and negative charged SUSPENSIONS - a type of mixture in which regions in a particle can dissolve each solid particles are evenly dispersed other. Polar solutes tend to dissolve in throughout a liquid. polar solvents. For example, table sugar SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25  SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY (polar) dissolves in water (polar) but not in oil (nonpolar) and Nonpolar solutes dissolve in nonpolar solvents. For example, grease (nonpolar) dissolves in gasoline (nonpolar) but not in water (polar). Ionic compounds also dissolve in polar solvents. For example, table salt and baking soda. These substances dissociate into particles called ions when mixed with polar solvents such as water. 3. Rate of Stirring The faster the stirring, the faster the Regardless of temperature, the nature of solute dissolves in a solvent. the solute affects how fast it will dissolve in a solvent. 4. Particle Size 2. Temperature The smaller the solute particle, the The solubility of gases in liquids decreases faster it will dissolve in a solvent. with increase in temperature. This is because the increase in temperature increases the energy of the gas molecules, making the bonds 5. Pressure between the gas and solvent molecules break. Pressure has little effect on the solubility For example, when bubbles emerge as water is of solid and liquid solutes in liquid heated even below its boiling temperature. solvents. For most solid solutes dissolved in But they have a significant effect on the liquid solvents, the solubility increases with solubility of gases in liquids. This principle temperature rises. For example, more was established by English Chemist sugar can dissolve in hot water than in William Henry (1774-1836). cold water. He proved Henry’s Law which states that the solubility of a gas in a liquid is directly The hotter the solvent, the faster the proportional to the pressure of the gas solute will dissolve. above the liquid. When more gas solute is introduced above a liquid solvent in a closed container, the pressure of the gas on the liquid increases, and more solute will dissolve in the liquid. This law is used in carbonated beverages, where carbon SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25  SCIENCE 7 MIDTERM | LECTURE S.Y. 2024-2025 | SECOND TERM SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY dioxide is dissolved under high pressure Percent by Volume inside the container. - Is the amount in a given volume of solution. CONCENTRATION OF SOLUTIONS (pages 56-57) The concentration of a solution expresses the amount of solute dissolved Percent by Mass and Volume in a given quantity of solvent or solution. This expression relates the mass of It can be expressed qualitatively and the solute to the volume of the solution. quantitatively. Percent by Mass: - Is the amount of solute in a given mass of solution. Percent by mass is commonly used for solid solutions or alloys. For example: nichrome wire is a solution of 75% nickel, 12% iron, 11% chromium, and 2% manganese by mass. SHELF OF PEDANTIC WISDOM: YOUR FREE REVIEWERS AND STUDY BUDDY “Just because it’s hard, doesn't mean it’s impossible. You can do it! - SAC JHS ‘24-25