Amixture contains 35.07 grams of carbon dioxide, 27.93 grams of water vapor, 12.64 grams of nitrogen, and 5.54 grams of helium. the total pressure of the system is 12 atm, what is the partial pressure of the helium?
a. 0.88 atm
b. 0.82 atm
c. 0.073 atm
d. 0.068 atm

Explanation:

For this question, we must use Dalton's Law of Partial Pressures:

The partial pressure of a gas in a mixture of gases equals its mole fraction times the total pressure:

1. Calculate the number of moles of each gas.

2. Calculate the total moles

3. Calculate the mole fraction of helium

4. Calculate the partial pressure of helium:

a chemical reaction happens

explanation:

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.