All stable atoms are . a. positively charged, with the number of protons exceeding the number of electrons. b. negatively charged, with the number of electrons exceeding the number of protons. c. neutral, with the number of protons equaling the number of electrons. d. neutral, with the number of protons equaling the number of electrons, which is equal to the number of neutrons.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.

2. what two items do autotrophs take from the environment to produce their food? 3. what are the two items that are released during transpiration from leaves? 4. what are the two membranes of the system? a.what are the two stages of photosynthesis? what are the two parts of photosynthesis?

Organisms are classified as producer or consumers according to the way they ?