Use the reaction shown of solid iron and water forming solid iron oxide and hydrogen gas to calculate the mass of solid iron that must be used to
obtain 0.500 L of hydrogen gas at STP. 3Fe(s) + 4H20(l)-> Fe3O4(s) + 4H2(g) *
a. 1.50 g
b. 1.66 g
c. 1.24g
d. 0.935 g

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

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.