When a 4.2 gram sample of mercury (Il) oxide, HgO is decomposed into its elements by • heating, 3.2 grams Hg is obtained and the rest is oxygen. What is the percent
composition of mercury and oxygen?

Hg = (3.2 : 4.2) x 100% = 76.19%

O = (1 : 4.2) x 100% = 23.81%

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

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 : )