Answer:
Oxygen.
Step-by-step explanation:
Hello!
In this case, since the ideal gas equation allows us to compute the moles of oxygen in 5.60 L at STP (1 atm and 273.15 K) as shown below:
![PV=nRT\\\\n=(PV)/(RT)=(1atm*5.60L)/(0.08206(atm*L)/(mol*K)*273.15K)\\\\n_(O_2)= 0.25mol](https://img.qammunity.org/2022/formulas/chemistry/college/nuofe7bepvwv2nyqnzmkx82hbeoavpa5iv.png)
Next, given the molar mass of carbon dioxide (44.01 g/mol) we compute the moles in 10.0g of this gas via:
![n_(CO_2)=10.0gCO_2*(1molCO_2)/(44.01gCO_2) =0.23molCO_2](https://img.qammunity.org/2022/formulas/chemistry/college/wvgr40rf8xmqnaos7v8wu7h7wv2l462w7y.png)
Thus, since oxygen has the greatest number of moles, we immediately infer it also has the greatest number of molecules based on the Avogadro's number.
Best regards!