Solid sodium metal reacts with liquid water to produce aqueous sodium hydroxide and hydrogen gas as shown by the chemical equation: 2 Na(s) +2H2O(I) —> 2 NaOH(aq) +H2(g)

How many grams of water are used in this reaction to form 4.0 g or hydrogen gas?

A) 36 g

B) 72 g

C) 80 g

D) 8 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

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

elements make up everything, and they combine to make compounds.

the answer is c