Hoja de repaso: Essential Science Fundamentals

📋 Course Outline

1. Photosynthesis and plant nutrition
2. Respiration and genetics
3. Atoms and the periodic table
4. Metals and chemical reactions
5. Energy, heat and electricity
6. Magnetism and exam skills

📖 1. Photosynthesis and plant nutrition

🔑 Key Concepts & Definitions

• Photosynthesis : Photosynthesis is the process where plants make their own glucose using light energy.
• Chloroplasts : Chloroplasts are the cell structures where photosynthesis takes place.
• Chlorophyll : Chlorophyll is the pigment that absorbs light energy for photosynthesis.
• Glucose : Glucose is the carbohydrate produced by photosynthesis that can be used or stored by plants.

📝 Essential Points

• Photosynthesis word equation is Carbon dioxide + Water → Glucose + Oxygen.
• Chlorophyll absorbs light energy, so plants need it to photosynthesise.
• Glucose can be used for respiration, stored as starch, or used to make cellulose.
• Factors affecting photosynthesis include light intensity, carbon dioxide concentration and temperature.

💡 Memory Hook

Chlorophyll turns light into glucose (food), giving oxygen away.

📖 2. Respiration and genetics

🔑 Key Concepts & Definitions

• Aerobic respiration : Aerobic respiration is the type of respiration that uses oxygen to release energy from glucose.
• Anaerobic respiration : Anaerobic respiration is the type of respiration that does not use oxygen.
• Lactic acid : Lactic acid is produced in muscles during anaerobic respiration.
• DNA : DNA carries genetic information used to produce inherited characteristics.

📝 Essential Points

• Aerobic respiration equation is Glucose + Oxygen → Carbon dioxide + Water.
• Anaerobic respiration in muscles produces lactic acid.
• Respiration happens in mitochondria.
• Genes are sections of DNA and chromosomes are found in the nucleus.

💡 Memory Hook

With oxygen you get CO2 + water; without oxygen you get lactic acid in muscles.

📖 3. Atoms and the periodic table

🔑 Key Concepts & Definitions

• Conservation of mass : Conservation of mass is the idea that mass is neither created nor destroyed in chemical reactions.
• Elements : Elements are substances made from only one type of atom.
• Compounds : Compounds are substances where elements are chemically joined together.
• Mixtures : Mixtures are combinations where substances are not chemically joined.

📝 Essential Points

• In chemical reactions, atoms rearrange to form new substances.
• Air is a mixture, while water is a compound.
• Periodic table groups are columns and periods are rows.
• Metals are on the left side and non-metals are on the right side.

💡 Memory Hook

Compounds are chemically joined; mixtures are just mixed together.

📖 4. Metals and chemical reactions

🔑 Key Concepts & Definitions

• Oxidation : Oxidation is a reaction where a substance gains oxygen.
• Reactivity series : The reactivity series ranks metals from most reactive to least reactive.
• Displacement reaction : A displacement reaction occurs when a more reactive metal replaces a less reactive metal.
• Electrolysis : Electrolysis is a process used to extract reactive metals from their compounds.

📝 Essential Points

• Oxidation example: Magnesium + Oxygen → Magnesium oxide.
• In the reactivity series, potassium is more reactive than sodium and calcium and so on down the list.
• A more reactive metal displaces a less reactive metal, e.g., Magnesium + copper sulfate → magnesium sulfate + copper.
• Metals + acid → salt + hydrogen, e.g., magnesium + hydrochloric acid → magnesium chloride + hydrogen.

💡 Memory Hook

More reactive = it can swap places (displace) with the less reactive metal.

📖 5. Energy, heat and electricity

🔑 Key Concepts & Definitions

• Energy stores : Energy stores are places energy is held, such as kinetic, thermal and chemical stores.
• Efficiency : Efficiency is the fraction of total energy input that becomes useful output energy.
• Renewable energy : Renewable energy comes from sources that do not run out quickly.
• Work : Work is done when a force acts to move an object through a distance.

📝 Essential Points

• Kinetic energy: Ek = 1/2 mv² and gravitational potential energy: Ep = mgh.
• Elastic potential energy: Ee = 1/2 ke².
• Efficiency = useful energy output ÷ total energy input × 100, so 40% efficiency comes from 40 J out of 100 J.
• Heat transfers by conduction, convection and radiation; dark matt surfaces absorb best and shiny surfaces reflect; loft insulation and double glazing reduce heat loss.

💡 Memory Hook

Dark matt absorbs, shiny reflects, and efficiency is useful ÷ total × 100.

📖 6. Magnetism and exam skills

🔑 Key Concepts & Definitions

• Electromagnet : An electromagnet is a magnet made when a current flows through a coil of wire.
• Magnetic field lines : Magnetic field lines show the direction of the magnetic field from north to south.
• Series circuit : A series circuit has a single path for current with one loop.
• Parallel circuit : A parallel circuit has branches so current can split.

📝 Essential Points

• Current is the flow of charge, and the circuit equation is V = IR.
• Opposite poles attract and like poles repel.
• Electromagnets get stronger with more coils and more current.
• Exam skills: learn definitions exactly, revise equations regularly, show working and include units, draw diagrams clearly, practise past paper questions.

💡 Memory Hook

Like repels, unlike attracts; more current/coils makes an electromagnet stronger.

📊 Synthesis Tables

Metals vs non-metals

Property	Metals	Non-metals
Appearance	Shiny	Dull
Conductivity	Conduct electricity	Poor conductors
Malleability	Malleable	Brittle

⚠️ Common Pitfalls & Confusions

1. Mixing up chloroplasts and chlorophyll: chloroplasts are the site, chlorophyll absorbs the light energy.
2. Swapping respiration types: aerobic uses oxygen while anaerobic does not.
3. Using the wrong respiration equation or products for aerobic versus anaerobic conditions.
4. Confusing conservation of mass with creation/destruction of atoms; atoms rearrange but are not created or destroyed.
5. Mixing up periodic table layout: groups are columns and periods are rows.
6. Thinking oxidation means adding electrons; in this course oxidation means gaining oxygen.
7. Confusing series and parallel circuits: series has one loop, parallel has branches.

✅ Exam Checklist

1. Write the photosynthesis word equation and state that it happens in chloroplasts.
2. Explain the role of chlorophyll and link it to absorbing light energy.
3. List three ways plants can use glucose and name two factors affecting photosynthesis.
4. Write the aerobic respiration word equation and identify the role of oxygen.
5. State what happens in anaerobic respiration in muscles and name the product.
6. Identify where respiration happens (mitochondria) and distinguish DNA, genes and chromosomes.
7. State what atoms do in reactions and apply conservation of mass to explain rearrangement.
8. Classify substances as element, compound or mixture using the idea of chemical joining.
9. Name periodic table features: groups vs periods and metals vs non-metals positions.
10. Use the oxidation idea for oxygen gain and write the given magnesium oxidation example equation.
11. Apply the reactivity series idea to predict displacement and extract the correct direction (more reactive displaces less reactive).
12. Use the displacement and metals + acid reaction forms to write products shown in the examples.
13. Choose the correct energy equations (Ep, Ek, Ee) and calculate efficiency using useful/total × 100.
14. Describe heat transfer modes and match dark matt vs shiny surfaces and insulation/double glazing to reduced heat loss.