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Started slowing down as magnesium disappeared. Some HCl went out the stopper. Some bubbles stuck to the side of the tube and to the string. Magnesium eventually disappeared. 
 Calculations: 
 
 
 
 Number of moles of magnesium 0.04/24.30 =  0.00165 mol es of hydrogen reacted. 
 Partial pressure of hydrogen 29.00*2.54/10 = 736.6 mmHg 736.6-19.25 = 717.35 717.35/760 =  0.944 atm of hydrogen 
 Volume at 1 atm P 1 V 1 =P 2 V 2 

 0.944*44.85=1.00*V 2 V 2 = 42.3mL 
 Volume at 273.15  o K V 1 /T 1 =V 2 /T 2 

 42.3/(21.5+273.15)=V 2 /273.15 V 2 = 39.2mL 
 Volume of 1 mol hydrogen at STP (29.2/1000)/0.00165= 23.8 mol hydrogen 
 
 
 
 Conclusion: 
 The purpose of this lab was to calculate the molar volume of hydrogen. We achieved this by mixing a known amount of magnesium with HCl to form hydrogen gas in a eudiometer. We used he mass of the magnesium to find the moles of Mg and H 2 , calculated the partial pressure of H 2 , standardized it to STP, and converted that to density of H 2 at STP. It was calculated to be 23.8 mol.