State two precautions that a student must take in order for the chromatography to be carried out successfully and explain why.​

What role does weathering have in shaping earth’s surface? a) it allows sediments to fall out of a medium. b) it sediments settle on a new surface. c) it breaks down older material into sediments. d) it transports sediments to a different location. will give brainliest, answer quickly.

Which of the following reactions is endothermic? h2(g) + ½ o2(g) h2o(g), h = -57.82 kcal ½n2(g) + o2(g) + 8.1 kcal no2(g) ½ n2(g) + 3/2 h2(g) nh3(g) + 11.0 kcal c(diamond) + o2(g) co2, h = -94.50 kcal

The density of e85 fuel is 0.801 g/ml. what is the mass of 1.00 gallon of the fuel? (1 gal. = 3.785 l)