HELP PLS! I NEED TO GET THIS RIGHT! Curious Carl and his lab partner were conducting a variety of experiments to produce gases: hydrogen, oxygen, and carbon dioxide. In one experiment, they added a piece of magnesium ribbon to 10 milliliters of hydrochloric acid. They observed bubbles being produced and did a variety of tests to identify the escaping gas; it proved to be hydrogen The reaction is represented by the following equation:
Mg + 2HCL -> MgCL2 + H2(g)

Assuming STP, how many moles of hydrogen gas did Carl and his partner collect if they collected 5.6L?
a. .250 moles
b. 2.78 moles
c. 5.60 moles
d.11.2 moles

In this case, since we can see how the hydrogen is given off as a product of the reaction and we can model its behavior via the ideal gas equation, it is possible for us to use such equation for the determination of the collected moles:

[tex]PV=nRT\\\\n=\frac{PV}{RT}[/tex]

Next, since the STP conditions account for a pressure of 1 atm and a temperature of 273 K, the moles turn out to be:

[tex]n=\frac{1atm*5.6}{0.08206\frac{atm*L}{mol*K}*273K}\\\\n=0.250mol[/tex]

Thus the answer is a. .250 moles .

Best regards!