I NEED HELP ASAP IN ON TIMER Why was Becquerel’s experiment a first step in discovering radioactivity?

A. It showed that a substance could phosphoresce when it was not exposed to light.

B. It showed that the substance that was used by Becquerel could phosphoresce.

C. It showed that a substance could constantly emit radiation even if it was not exposed to light.

D. It showed that a substance emitted radiation when it was exposed to light.

)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.

What factor besides temperature affects the boiling point of water? a. mass b. number of moles c. volume d. pressure

Bridget is in science class. her teacher gives her two unknown substances and asks her to determine their relative ph. she places a piece of red litmus paper into both substances. the litmus paper turns purple when she places it into substance i. the litmus paper turns blue when she places it into substance ii. a. substance i is a neutral substance and substance ii is an acid. b. substance i is a neutral substance and substance ii is a base. c. substance i is an acid and substance ii is a base. d. substance i is a base and substance ii is a neutral substance.