Chapter 2: The Human Organism and the Power of Energy

1. Chapter 2: The Human Organism and the Power of Energy

2. What is energy? • You may sometimes feel like you are having too much work and not enough energy to do the work! Energy is the Capacity to do work or to produce change. • Homework induces a change in your brain: connections between neurons are formed, therefore it requires energy.

3. Unit of energy: The standard unit of energy is the ___________ Joule (J) . One Joule represents the energy needed to lift an object weighing one Newton (N) to the height of one meter (m). 1 Joule 100 g 100 g 1 meter 100 g 100 g On earth 1N = 100 g

4. Calorie 15°C  16°C

5. Thermal energy • The energy, that is contained in the agitation of the molecules.

6. Thermal Energy Less Thermal Energy More Thermal Energy 4°C 1L 15°C 1L

7. Thermal energy • The energy, that is contained in the agitation of the molecules. • The amount of thermal energy, that a substance contains, depends on the degree of agitation of its molecules (temperature)… • … and on how much substance there is.  Which contains more thermal energy? 50°C 80°C ✓

8. Examples of work or change induced by thermal energy. • Melting of snow. • Lifting of a hot air balloon by heating the air.

9. Radiant energy • … is the energy contained in and transported by electromagnetic waves

10. Radiant Energy Electromagnetic waves:  transport energy from one place to another. • The amountof transported energy depends on the wavelength and the quantity of radiation. • The shorter the wavelength of a given number of waves the more energy the wave can transport.

11. Radiant Energy Less Energy More Energy

12. Examples of work or change induced by radiant energy. • Food is heated by microwaves • Getting suntanned or burned from ultraviolet rays

13. Density • Mass per unit of Volume • Measured in g/mL

14. Mechanical energy • .. Is the energy that results from the _____of an object, its _____, and its _____________ _____________. speed relationship to mass its surrounding

15. Mechanical Energy - speed More fast Less slow

16. Mechanical Energy - mass Less light heavy More

17. Mechanical Energy - position More Less

18. Mechanical energy • .. Is the energy that results from the _____of an object, its _____, and its _____________ _____________. • The greater the speed the greater the mechanical energy. • The greater the mass the greater the mechanical energy. • The higher the object the greater its mechanical energy. speed relationship to mass its surrounding

19. Examples of work or change induced by mechanical energy. • Crater caused by an asteroid. • Electricity generated by spinning a turbine (hydro + wind). • Dent in a car from a crash.

20. Chemical Energy • … is the energy stored in the bonds of a molecule • Energy is stored when bonds are formed … • … and can only be released when bonds are broken and reorganized.

21. Chemical Energy Glucose Photosynthesis CO2 + H2O Energy Stored

22. Chemical Energy Glucose Respiration CO2 + H2O Energy Released

23. Chemical Energy • … is the energy stored in the bonds of a molecule • Energy is stored when bonds are formed … • … and can only be released when bonds are broken and reorganized. • The amount of energy stored in a molecule depends on the strength and the number of bonds.

24. Examples of work or change associated with chemical energy. • combustionof gasoline Driving of a car. • Photosynthesis: light energy  chemical energy • Cellular respiration: chemical energy animals grow move and think.

25. Other Forms of Energy

26. Energy transfer • Energy transfer is the movement of energy from one place to another:

27. Heat / Heat transfer Heat is the transfer of thermal energy from one place to another. Energy • The molecules in the drink transfer thermal energy to the cup  the cup gets warm. • The molecules of the cup transmit vibration energy to the molecules of our skin. • Agitation of the molecules in our skin feels warm to us.

28. Transformation of energy • The transformation of energy is the change of one form of energy into another. light chemical electrical thermal mechanical mechanical chemical chemical

29. Terms to Know • Matter • Pure Substance • Compound • Element • Molecule • Particle • Characteristic Chemical Property • Characteristic Physical Property • Mixture • Heterogeneous • Homogeneous • Colloid • Solution • Solute • Solvent • Solubility • Concentration • Dilution

30. Particle Model • Matter is made up of particles that are in constant motion. • Particles in a solid are very close together and move very little. • Particles in a liquid are close together and move more than the particles in a solid but less than particles in a gas • Particles in a gas are very far apart and move a lot.

31. Matter mixtures Pure substances heterogeneous homogeneous compounds elements Contain only one type of particle Suspension Colloid Solution ✗ ?

32. Separation Techniques • Decantation • Centrifugation • Filtration • Evaporation • Distillation • Chromatography

33. Characteristic physical properties • Melting Point • Boiling Point • Density • Solubility • Do not change the substance during the identification process.

34. Chemical characteristic properties

35. Which purification technique would be leastuseful in separating a mixture of two liquids? • Decantation • Filtration • Centrifugation • Distillation

36. Which of the properties in the table below can help us identify the unknown substance tested? Identify the Unknown using Apendix 1 in your textbook p. 418-423

37. Identify the following as Homogeneous or Heterogeneous • A bowl of Cereal: ______________________ • A Toonie: __________________ • Chocolate Milk: __________________ • Blood: ___________________ Heterogeneous Heterogeneous Homogeneous Homogeneous