7. Energy can be described in many ways. Explain the following:
Diagram
Graphical representation
Models
8. Refer to the softball player on page 68. What is her source of kinetic energy? Where
did this energy come from?

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

Light waves can move through , but they travel fastest when they move through a(n) .

Which of the following is not an assumption that scientists must make about the natural world? a. regularity b. causality c. predictability d. plausibility