How many grams of water are produced from the reaction of 7.51 grams of Hydrogen gas with excess oxygen
H2 + O2 —> H2O

The answer to your question is 67.5 g of H₂O

Explanation:

Data

mass of water = ?

mass of H₂ = 7.51 g

mass of O₂ = excess

Balanced chemical reaction

                2H₂  +  O₂  ⇒   2H₂O

Process

1.- Calculate the molar mass of H₂ and H₂O

H₂ = 2(1 x 2) = 4 g

H₂O = 2[(2 x 1) + (16 x 1)] = 2[18] = 36 g

2.- Use proportions and cross multiplication to find the answer

                     4 g of H₂ 36 g of H₂O

                   7.5 g of H₂    x

                           x = (7.5 x 36) / 4

                           x = 270 / 4

                           x = 67.5 g of H₂O

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

hope this : )