General, Organic, and Biochemistry, 7e

1. General, Organic, and Biochemistry, 7e Bettelheim, Brown, and March

2. Chapter 1 Matter, Energy, and Measurement

3. Chemistry • Chemistry is the study of matter • matter is anything that has mass and takes up space • Matter can change from one form to another • in a chemical reaction (chemical change), substances are used up and others formed in their place Example: when propane (bottled gas) burns in air, propane and oxygen are converted to carbon dioxide and water • in a physical change, matter does not lose its identity Example: ice (solid water) melts to become liquid water; liquid water boils to become steam (gaseous water)

4. Scientific Method

5. Exponential Notation • Used to represent very large or very small numbers as powers of 10 • Examples: 0.00002 is written as 2 x 10-5 2,000,000 is written as 2 x 106

6. Metric System • Base units in the metric system

7. Metric System • The most common metric prefixes

8. Metric & English Systems • Some conversion factors

9. Mass and Weight • Mass: the quantity of matter in an object • mass is independent of location • Weight: the result of mass acted upon by gravity • weight depends on location; depends on the force of gravity at the particular location

10. Temperature • Fahrenheit (F): defined be setting freezing point of water at 32°F and the boiling point of water at 212°F • Celsius (C): defined by setting freezing point of water at 0°C and boiling point of water at 100°C • Kelvin (K): zero is the lowest possible temperature; also called the absolute scale • degree is the same size as Celsius degree • K = °C + 273

11. Factor-Label Method • Conversion factor • a ratio, including units, used as a multiplier to change from one system or unit to another • for example, 1 lb = 463.6 g • Example: convert 381 grams to pounds • Example: convert 1.844 gallons to milliliters

12. The Three States of Matter • Gas • has no definite shape or volume • fills whatever container it is put into • is highly compressible • Liquid • has no definite shape but a definite volume • is slightly compressible • Solid • has a definite shape and volume • is essentially incompressible

13. Density • Density: the ratio of mass to volume • most commonly used units are g/mL for liquids and solids, and g/L for gases. • Example: If 73.2 mL of a liquid has a mass of 61.5 g, what is its density in g/mL?

14. Specific Gravity • Specific gravity: the density of a substance compared to water as a standard • because specific gravity is the ratio of two densities, it has no units (it is dimensionless) • Example: the density of copper at 20°C is 8.92 g/mL. The density of water at this temperature is 1.00 g/mL. What is the specific gravity of copper?

15. Energy • Energy: the capacity to do work • may be either kinetic energy of potential energy • the calorie (cal) is the base metric unit • Kinetic energy: the energy of motion • KE increases as the object’s velocity increases • at the same velocity, a heavier object has greater KE • Potential energy: the energy an object has because of its position; stored energy

16. Energy • Examples of kinetic energy are mechanical energy, light, heat, and electrical energy • In chemistry, the most important form of potential energy is chemical energy • chemical energy is stored in chemical substances, as for example in foods such as carbohydrates and fats • it is given off when substances take part in chemical reactions • The law of conservation of energy • energy can neither be created nor destroyed • energy can only be converted from one form to another

17. Heat and Temperature • Heat is a form of energy • heating refers to the energy transfer process when two objects of different temperature are brought into contact • heat energy always flows from the hotter object to the cooler one until the two have the same temperature • heat is commonly measured in calories (cal), which is the heat necessary to raise the temperature of 1 g of liquid water by 1°C

18. Specific Heat • Specific heat: the amount of heat necessary to raise the temperature of 1 g of a substance by 1°C.

19. Specific Heat • The following equation gives the relationship between specific heat, amount of heat, the mass of an object, and the change in temperature • Example: how many calories are required to heat 352 g of water from 23°C to 95°C?

20. Matter, Energy, and Measurement End Chapter 1