Mine Rescue Statements of Fact - Test No. 3 Questions taken from the 2016 Coal Mine Rescue Statements of Fact - Group B Progress Indicator: Question 2 of 20 2.  The term partial pressure of gases refers to: Choices: The concentration of a gas in a mixture of other gases The concentration of a single gas unmixed with other gases The pressure a gas exerts in a mixture of other gases The pressure of a single gas unmixed with other gases