4. which hypothesis led to the discovery of the proton?
a. cathode rays should be attracted to a positively-charged plate.
b. the nucleus of an atom should contain neutrons.
c. when a neutral hydrogen atom loses an electron, a positively-charged
particle should remain.
d. a proton should be 1840 times heavier than an electron.

If the density of water is 1.0 g/cm3, which of these materials would float in water, based on their densities? check all that apply. aluminum cork iron lead wax

What are transitions between a liquid and gas called? identify which way they are transitioning

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.