Why do our hair become grey?

Scientist wants to react a barium chloride salt with an acid. to speed up the reaction, the scientist crushes the barium chloride salt until it is a fine powder. this speeds up the reaction by a. increasing the ph of the salt. b. increasing the surface area of the salt. c. increasing the pressure of the salt. d. increasing the temperature of the salt. im thinking more a not 100% sure

When the earth was formed and cooled, why did nickel and iron end up in the center of the earth while basalt and granite ended up in the outer layers

Butadiene undergoes a reaction at a certain temperature in the gas phase as follows: 2c4h6(g) --> c8h12(g) the following data were collected for this reaction: time (min) [c4h6] (m) 0 0.36 15 0.30 30 0.25 48 0.19 75 0. determine the order of the reaction and the rate constant. 1st order and k = 4.3x10 -4 s-1 1st order and k = 2.3x10-4 s-1 2nd order and k = 4.3x10-4 s-1 2nd order and k = 2.3x10-4 s-1 zero and k = 4.3x10-4 s-1