Atotal of 0.829 l of hydrogen gas is collected over water at 33.0°c. the total pressure is 794 torr.
if the vapor pressure of water at 33.0°c is 13.2 torr, what is the partial pressure of hydrogen?

P(H₂) = 807.2 torr

Explanation:

According to the Dalton law, the pressure of mixture of a gas is sum of the partial pressure of its mixing component gases.

P(total) = P1 + P2 + P3 +

In given problem,

Total pressure is = 794 torr

Partial pressure of water = 13.2 torr

Partial pressure of hydrogen = ?

Solution:

P(total) = P(H₂O)  + P(H₂)

P(H₂) = P(total) - P(H₂O)

P(H₂) = 794 torr - 13.2 torr

P(H₂) = 807.2 torr

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

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.