Carbon monoxide (co) gas reacts with oxygen (o2) gas to produce carbon dioxide (co2) gas. if 1.00 l of carbon monoxide reacts with excess oxygen at standard temperature and pressure, what volume of carbon dioxide is produced?

1) Chemical equation:

2CO + O2 ---> 2CO2

2) molar ratios 2 moles CO : 1 mol O2 : 2 moles CO2.

3) When temperature and pressure is kept constant, the molar ratios are equal to the volume ratios.

So, at the same temperature and pressure conditions (standard) you ca state

2 L CO : 1 LO2 : 2 L CO2

=> 2L CO : 2 L CO2 => 1L CO : 1 L CO2.

So, 1 liter of CO2 is produced when 1 liter of CO reacts with excess O2.

Yes it would be a physical change.