It's peggy sue's birthday and she's about to blow out the candles on her cake. brother roger stops the party when he shouts: "look at that! chemical and physical changes taking places on your birthday cake! "
how would you respond to roger?
a) roger is incorrect. the melting wax is a physical change but there is no chemical change taking place.
b) roger is correct. lighting the match is a chemical change and burning the candles is a physical change.
c) roger is correct. the melting wax is a physical change and the burning candle wick is a chemical change.
d) roger is incorrect. only a chemical change is taking place as evidenced by the light and heat of the burning candles.

Which type of bonding involves the complete transfer of a valence electron from a less electrogrative atom to a more electronegative one

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

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.