Place an empty 250 mL beaker on the balance and record its mass. Add your unknown rubber stopper to the beaker and record the mass again. Subtract these two values (with correct Sig. Fig.) to calculate the mass of the rubber stopper. (This technique is known as weighing by difference) b) Mass of an empty 250 mL Beaker (g) 155.625 g c) Mass of the 250 mL Beaker and Rubber Stopper (g) 180.825 g d) Mass of the unknown Rubber Stopper (g)

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

wher is the rest of the question