Astudent finds a container of gases in the laboratory classroom with a total pressure reading of 655 mmhg. the label on the container describes the contents as 5.00 g of carbon dioxide gas and 3.75 g of helium gas. calculate the partial pressure of carbon dioxide in the container in mmhg.

70.8 mmHg

Explanation:

To find partial pressure of carbon dioxide we first find the mole fraction of carbon dioxide

n (carbon dioxide) = 5/44.01 g/mol = 0.11361 mol

n (Helium) = 3.75 g/4 g/mol = 0.9375 mol

The partial pressure of carbon dioxide will be the mole fraction of carbon dioxide multiplied by the total pressure

Partial pressure = 0.11361g/(0.11361g + 0.9375 g)* 655 mmHg

                          = 70.8 mmHg

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.