Untitled Flashcards Set

CHEMISTRY

1. Difference between qualitative and quantitative observations:

   • Qualitative observations are descriptive and include characteristics that can be observed but not measured (e.g., color, smell).

   • Quantitative observations involve measurements and are expressed as numbers (e.g., height, mass).

2. Ionic bonds and covalent bonds:

   • Ionic bonds are formed when electrons are transferred from one atom to another, resulting in positive and negative ions.

   • Covalent bonds occur when two atoms share electrons.

3. Formation of an ion:

   • An ion is formed when an atom gains or loses electrons.

   • An anion is a negatively charged ion (gains an electron), and a cation is a positively charged ion (loses an electron).

4. Physical and chemical properties:

   • Physical properties can be observed without changing the substance (e.g., color, melting point).

   • Chemical properties describe how a substance reacts with other substances (e.g., flammability, reactivity).

5. Physical and chemical changes:

   • Physical changes alter the form of a substance but not its chemical composition (e.g., melting ice).

   • Chemical changes result in the formation of new substances (e.g., rusting iron).

6. Particle Theory of Matter:

   • All matter is made up of tiny particles.

   • These particles are in constant motion.

   • The temperature affects the movement of the particles.

   • There are attractive forces between particles.

7. Neutrons, protons, and electrons:

   • Neutrons: No charge, located in nucleus, mass ~1 amu.

   • Protons: Positive charge, located in nucleus, mass ~1 amu.

   • Electrons: Negative charge, orbiting nucleus, mass ~0 amu.

8. Classifications of matter:

   • Compound: A substance made from two or more different atoms (e.g., water, H₂O).

   • Molecule: Two or more atoms bonded together (could be the same or different).

   • Mechanical mixture: A combination of different substances that retain their individual properties (e.g., salad).

   • Homogeneous mixture: A mixture that is uniform throughout (e.g., saltwater).

9. Bohr-Rutherford diagrams:

   • These are visual representations of the arrangement of electrons in an atom. They show energy levels with electrons orbiting the nucleus. Atoms bond by sharing or transferring electrons.

10. Calculating neutrons, protons, and electrons:

• Use the atomic mass (rounded to the nearest whole number) to find protons and neutrons (neutrons = atomic mass - protons). The number of electrons equals the number of protons in a neutral atom.

11. How an atom becomes charged:

• An atom becomes charged by gaining or losing electrons, producing ions.

12. Properties/Names of groups in the Periodic Table:

• Groups include:

  • Alkali metals (Group 1), highly reactive.

  • Alkaline earth metals (Group 2), less reactive.

  • Transition metals (Groups 3-12), various properties.

  • Non-metals (e.g., oxygen, chlorine), typically poor conductors.

  • Metalloids (e.g., silicon), exhibit properties of metals and non-metals.

13. Difference between a molecule and a compound:

• A molecule is any two or more atoms bonded together, while a compound is a molecule that contains at least two different types of atoms.

PHYSICS

14. Insulators and conductors:

• Insulators: Materials that do not allow electrical current to flow easily (e.g., rubber).

• Conductors: Materials that allow electrical current to flow easily (e.g., copper).

15. Electrons being grounded:

• Grounding provides a path for excess charge to dissipate into the earth, neutralizing the charge of an object.

16. Law of Attraction and Repulsion:

• Like charges repel; opposite charges attract.

17. Determining charge of an object:

• Objects can be labeled as positive (+), negative (-), or neutral based on their electron gain or loss.

18. Ammeters, Voltmeters, and Ohmmeters:

• Ammeters measure electric current in amperes (A).

• Voltmeters measure electric potential difference in volts (V).

• Ohmmeters measure electrical resistance in ohms (Ω).

19. Ways to charge an object:

• Friction: Rubbing two objects together.

• Conduction: Transfer of charge through direct contact.

• Induction: Charge is transferred without direct contact, usually through electric fields.

20. Static cling:

• A phenomenon where clothing sticks together due to static electricity.

• Adding fabric softener sheets in the dryer can minimize static cling.

21. Using the electrostatic series:

• The series helps determine which materials will cling more to each other based on their position in the list.

22. Difference between series and parallel circuits:

• Series circuit: Components are arranged in a single path, so current flows through each component in sequence.

• Parallel circuit: Components are arranged in multiple paths, so current can flow through different paths simultaneously.

23. Drawing circuit diagrams:

• Use symbols to represent components (battery, resistor, switch, etc.) and depict connections between them.

24. Main parts of an electric circuit:

• Source: Provides voltage (e.g., battery).

• Conductor: Wire that connects components.

• Load: Device that uses electrical energy (e.g., bulb).

• Switch: Controls the flow of electricity.

25. Current, voltage, and resistance:

• Current (I): Flow of electric charge, measured in amperes (A).

• Voltage (V): Electric potential difference, measured in volts (V).

• Resistance (R): Opposition to current, measured in ohms (Ω).

26. Calculating current, voltage, and resistance:

• Use Ohm's Law: V = I × R (Voltage = Current × Resistance).

• Current and voltage values depend on whether circuits are series or parallel.

27. Calculating % efficiency:

• Efficiency (%) = (Useful output energy / Total input energy) × 100.

• Compare devices based on their efficiency ratings.

28. Renewable and non-renewable energy sources:

• Renewable: Solar, wind, hydro, geothermal.

• Non-renewable: Coal, natural gas, oil, nuclear.

BIOLOGY

29. High biodiversity in an ecosystem:

• Indicates a wide variety of species and genetic diversity, which contributes to ecosystem resilience and stability.

30. Four spheres of the earth:

• Atmosphere: Layer of gases surrounding Earth.

• Hydrosphere: All of Earth’s water.

• Lithosphere: Earth’s solid outer layer (rock and soil).

• Biosphere: Regions of the surface where life exists.

31. Sustainable ecosystem:

• An ecosystem that maintains its biodiversity and productivity over time without depleting resources.

32. Photosynthesis and word equation:

• The process where plants convert light energy into chemical energy using carbon dioxide and water.

• Word equation: Carbon dioxide + Water → Glucose + Oxygen.

33. Cellular respiration and word equation:

• The process in which cells convert glucose and oxygen into energy, carbon dioxide, and water.

• Word equation: Glucose + Oxygen → Carbon dioxide + Water + Energy.

34. Difference between producer and consumer:

• Producers: Organisms that produce their own energy via photosynthesis (e.g., plants).

• Consumers: Organisms that consume other organisms for energy (e.g., animals).

35. Difference between food chain and food web:

• A food chain is a linear sequence showing how energy is transferred from one organism to another.

• A food web is a complex network of interconnected food chains representing the feeding relationships in an ecosystem.

36. Drawing and explaining food chains and food webs:

• Food chains depict the flow of energy from producers to various levels of consumers.

• Food webs represent multiple overlapping food chains, demonstrating more complex relationships.

37. Ecosystem in equilibrium:

• An ecosystem is stable and can sustain species populations over time, with balanced birth and death rates, and stable resource availability.

38. Fragmentation process and problems:

• Fragmentation refers to the breaking up of habitats into smaller, isolated patches.

• Problems include reduced biodiversity, increased edge effects, and impaired animal movement.

39. Humans and climate change:

• Activities such as greenhouse gas emissions, deforestation, and fossil fuel consumption contribute to global warming and other environmental changes.

40. Benefits of organic farming:

• Promotes biodiversity, lowers chemical pesticide use, improves soil health, and can lead to healthier food products.

41. Positive and negative impacts of pesticides:

• Positive: Help control pest populations and increase crop yields.

• Negative: Can harm non-target species, lead to pest resistance, and contaminate soil and water.

42. Methods to control invasive species:

• Physical removal, biological control (introducing natural predators), chemical control (herbicides/pesticides), and preventive measures.

SPACE

43. Solar Nebula Theory:

• A model that explains the formation of the solar system from a giant cloud of gas and dust.

44. When we see a solar eclipse:

• A solar eclipse occurs when the Moon passes between the Earth and the Sun, blocking the Sun's light.

45. Facts about Earth:

• Earth has one moon and is part of the Milky Way galaxy.

46. Will the sun ever die?

• Yes, the Sun will eventually exhaust its nuclear fuel and expand into a red giant before shedding its outer layers and becoming a white dwarf.

47. Difference between a star and a planet:

• Stars are massive celestial bodies that produce their own light through nuclear fusion.

• Planets orbit stars, do not generate their own light, and are significantly smaller than stars.

48. How planets shine:

• Planets shine by reflecting light from the Sun.

49. Why Pluto is no longer a planet:

• Pluto was reclassified as a dwarf planet due to its size and the criteria set by the International Astronomical Union for defining a planet.

50. Everyday tasks in space:

• Astronauts adapt daily tasks (e.g., eating, sleeping) using specially designed equipment to manage microgravity challenges.

51. Communication with astronauts in space:

• Yes, communication is possible via radio transmissions and satellite links, allowing for instant contact with mission control on Earth.