Essential Chemistry, Biology, and Climate Facts for Students

Chemistry

Physical and chemical changes

1. Physical change is a change in form or state where no new substance is formed, while a chemical change produces a new substance.

2. Clues of a chemical change include gas production, color change, temperature change, formation of a precipitate, and light production.

3. Oxygen gas relights a glowing splint, carbon dioxide turns limewater cloudy, and hydrogen gas produces a popping sound with a burning splint.

4. The chemical families on the periodic table are alkali metals, alkaline earth metals, halogens, and noble gases.

5. A diatomic molecule is a molecule made of two atoms of the same element; the diatomic molecules are H₂, N₂, O₂, F₂, Cl₂, Br₂, and I₂.

6. An ion is a charged particle formed when an atom gains or loses electrons; Group 1 forms ⁺¹ ions, Group 2 forms ⁺² ions, Group 17 forms ⁻¹ ions, and Group 18 typically forms no ions.

Ionic, molecular, and other compounds

1. Ionic compounds are formed between metals and non-metals with electrons transferred, while molecular compounds are formed between non-metals with electrons shared.

2. Polyatomic ions are charged groups of atoms, and oxyacids are acids that contain oxygen.

3. Law of Conservation of Mass: mass is neither created nor destroyed in a chemical reaction.

4. If A + B → C + D and A = 12 g, B = 15 g, and C = 9 g, then D = 18 g.

5. Word equations describe reactions in words, chemical equations use symbols, and balanced equations have equal atoms on both sides.

6. The five types of reactions are synthesis, decomposition, single displacement, double displacement, and combustion.

7. Acids have a pH less than 7, produce H⁺ ions, and taste sour, while bases have a pH greater than 7, produce OH⁻ ions, and feel slippery.

pH and neutralization

1. The pH scale ranges from 0 to 14; acids are found below 7, bases are found above 7, and 7 is neutral.

2. A neutralization reaction occurs when an acid reacts with a base to form a salt and water.

Biology

16. The cell membrane controls what enters and leaves the cell, the cytoplasm holds organelles, the nucleus controls cell activities, the nuclear membrane protects the nucleus, and the nucleolus makes ribosomes.

17. Vacuoles store materials, mitochondria release energy, the Golgi apparatus packages proteins, lysosomes digest waste, and the endoplasmic reticulum transports materials.

18. Rough endoplasmic reticulum (Rough ER) has ribosomes and makes proteins, while Smooth ER makes lipids and detoxifies chemicals.

19. Centrioles help cell division, ribosomes make proteins, chromatin contains DNA, the cell wall provides support, and chloroplasts perform photosynthesis.

20. Plant cells have a cell wall, chloroplasts, and a large vacuole, while animal cells do not.

21. Diffusion is the movement of particles from high to low concentration, and osmosis is the diffusion of water across a membrane.

22. The cell cycle consists of interphase, mitosis, and cytokinesis; during interphase the cell grows and copies DNA.

23. Mitosis is the division of the nucleus and includes prophase, metaphase, anaphase, and telophase.

24. Cytokinesis is the division of the cytoplasm and occurs by a cell plate in plant cells and a cleavage furrow in animal cells.

25. Specialized cells have shapes that support their functions, such as red blood cells being thin to carry oxygen.

26. A mutation is a change in DNA, and cancer is uncontrolled cell division caused by mutations; cancer cells divide uncontrollably while normal cells do not.

27. Cells divide for growth, repair, and replacement.

28. Metastasis is the spread of cancer; malignant tumors are cancerous, benign tumors are non-cancerous, and a biopsy is the removal of tissue for testing.

29. Epithelial tissue protects, connective tissue supports, muscle tissue allows movement, and nervous tissue transmits signals.

30. Blood moves from the heart to the lungs for oxygen and then to the body before returning to the heart.

31. Red blood cells carry oxygen, white blood cells fight infection, platelets help clot blood, and plasma transports materials.

32. The circulatory and respiratory systems work together to exchange oxygen and carbon dioxide.

33. Air enters through the nose or mouth, travels through the trachea, bronchi, bronchioles, and reaches the alveoli.

34. Inhalation occurs when the diaphragm contracts and exhalation occurs when it relaxes.

35. Food travels through the mouth, esophagus, stomach, small intestine, large intestine, and exits through the rectum.

36. The epiglottis prevents food from entering the trachea and protects the airway.

37. Organ systems work together to keep the body functioning properly.

38. Diseases can affect systems such as asthma in the respiratory system and heart disease in the circulatory system.

39. Leaves perform photosynthesis, stems support and transport materials, and roots absorb water and minerals.

40. Plants have a root system for absorption and a shoot system for photosynthesis and reproduction.

41. Plant tissues include dermal, vascular, and ground tissues which protect, transport, and support the plant.

42. Stomata are pores on leaves and guard cells control their opening and closing.

43. Pollination occurs when pollen is transferred to the stigma and is essential for plant reproduction.

Climate

44. Weather refers to short-term atmospheric conditions, while climate refers to long-term averages.

45. Anthropogenic greenhouse gases include carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons (CFCs).

46. Albedo is the amount of sunlight reflected by a surface.

47. A climatograph represents average temperature and precipitation over a year.

48. Natural sources of carbon dioxide include volcanoes, respiration, decomposition, and forest fires.

49. Anthropogenic sources of greenhouse gases include burning fossil fuels, deforestation, agriculture, industry, and transportation.

50. Forests are considered carbon sinks because they absorb and store carbon dioxide through photosynthesis.