General Chemistry 2 - Past Lecture Notes (PDF)

GENERAL CHEMISTRY 2 MR. ALRIE M. PORRAS TEACHER by Alrie M. Porras Classroom Rules: 1. Listen when somebody is talking. 2. Participate in class activities. True or False: Density is a property that can help distinguish one substance from Answer: another. True Explanation: De...

GENERAL CHEMISTRY 2 MR. ALRIE M. PORRAS TEACHER by Alrie M. Porras Classroom Rules: 1. Listen when somebody is talking. 2. Participate in class activities. True or False: Density is a property that can help distinguish one substance from Answer: another. True Explanation: Density is a unique property for each substance and can be calculated as mass divided by volume. For instance, gold is denser than aluminum, making density a  True or False: Magnetism can be used to separate a mixture of iron and sulfur. Answer: True Explanation: Iron is magnetic, while sulfur is not. A magnet can be used to pull out the iron particles, leaving the sulfur behind.  True or False: Chromatography separates substances based on their solubility Answer: and interaction with a stationary phase. True Explanation: Chromatography separates components of a mixture by exploiting differences in how they move through a medium, based on their solubility and affinity to the stationary and  Boiling point is to identification as filtration is to ______. Answer: Separation Explanation: The boiling point is a unique property used to identify substances, while filtration is a method used to separate mixtures by removing insoluble solids  Density is to mass and volume as solubility is to ______ and ______. Answer: Solvent and temperature Explanation: Density depends on mass and volume, while solubility is determined by the interaction of a solute with a solvent and can change with temperature. Magnetism is to iron as chromatography is to ______. Answer: Pigments (or dyes) Explanation: Magnetism is used to separate iron from mixtures, while chromatography is often used to separate and identify pigments or dyes in mixtures. Evaporation is to liquid as distillation is to ______. Answer: Liquid and vapor Explanation: Evaporation involves a liquid turning into a vapor, while distillation involves both evaporation and condensation to separate substances based on boiling points.  Hardness is to mineral identification as solubility is to ______. Answer: Solution separation Explanation: Hardness helps identify minerals by testing their resistance to scratching, while solubility helps separate components in a mixture based on their ability to  WHAT DO YOU THINK OUR LESSON IS ALL ABOUT?  Use properties of matter to Learning identify substances Competenc and to separate them y: STEM_GC11MPIa- b-5 Objective s: 1 2 3 1. Use the 2. Apply the 3. Analyze the kinetic molecular correct use of these model to explain separation techniques in properties of technique based real-world liquids and solids on the properties scenarios like of matter in a chemical given mixture. analysis, water purification, and Introduction to Matter Matter has mass and occupies space. Composed of elements, compounds, and mixtures. Physical vs. chemical properties.  Physical vs. chemical properties Measured or Observed when observed substances interact without with others changing the substance's composition  Comparison table of physical vs. Properties of Matter chemical properties. Identifying Substances Methods Based on Physical Properties: Solubility (e.g., sugar Density dissolving in water). Melting and boiling points (e.g., identifying water from ethanol). Techniques for Separating Substances Physical Separation Methods: Filtration: Separate solids from liquids. Distillation: Separate substances with different boiling points. Chromatography: Separate based on solubility. Magnetic separation: For magnetic materials. Decantation: Separate Techniques for Separating Substances Physical Separation Methods: Filtration: Separate solids from liquids. Distillation: Separate substances with different boiling points. Chromatography: Separate based on solubility. Magnetic separation: For magnetic materials. Decantation: Separate liquids and solids by density. Chemical Separation Methods Examples: Reactivity with acids to isolate metals. Electrolysis to break down compounds. When to Use: When physical methods are insufficient. Real-Life Applications Water purification. Recycling materials. Forensic analysis (e.g., chromatography for detecting substances).  Summ ary Physical and chemical properties are essential in identifying substances. Various techniques are used for separation based on these properties.  Summ ary Practical applications are found in science, industry, and daily life. Questions and A separating Funnel can Discussion separate two immiscible How would you separate oil liquids, oil and water. and water? Because oil and water are Can you think of other fully insoluble in one other, properties for identifying they split into two distinct unknown substances? layers. 1. Which property of matter can be used to separate sand from water? a) Boiling point b) Filtration c) Density d) Solubility 2. What property is used to identify a substance by its resistance to being scratched? a) Solubility b) Hardness c) Melting point d) Density 3. Which separation technique uses boiling points to separate substances in a mixture? a) Chromatography b) Filtration c) Distillation d) Decantation 4. If a substance sinks in water, what can you infer about its density? a) It has a higher density than water. b) It has a lower density than water. c) Its density equals that of water. d) It has no density. 5. Which of the following properties is most useful for identifying a pure substance? a) Color b) Mass c) Boiling point d) Volume 6. What is the main property used in chromatography? a) Magnetic properties b) Solubility and interaction with the stationary phase c) Density differences d) Boiling point differences 7. Which method separates a mixture of salt and water? a) Filtration b) Evaporation c) Chromatography d) Magnetism 8. Which of these tools would best separate iron filings from a mixture? a) Filter paper b) Magnet c) Chromatography paper d) Distillation apparatus 9. What happens to the solubility of most solids in water as the temperature increases? a) It decreases. b) It remains constant. c) It increases. d) It fluctuates randomly. 10. Which separation method is used to recover pure water from saltwater? a) Decantation b) Distillation c) Filtration d) Sublimation