Answer:
25.0%
A solution of benzene (C6H6) and toluene (C7H8) is 25.0% benzene by mass. At 25 °C the vapor pressures of pure benzene and pure toluene are 94.2 torr and 28.4 torr, respectively.
4% starch solution will decrease in volume.
This is because the less starch concentration, the more water molecules exists. Since 4% is less than 10%, so the 4% will contain more water. Water molecules tend to flow from a region of higher water potential to a region of lower water potential through the semi permeable membrane in osmosis. Therefore, since the 4% contains more water, the water there will flow away from the 4% and to the 10% one in order to reach equilibrium.
Protons, neutron, and elecrons