Answer: I think it’s the first one
Answer: Total pressure inside of a vessel is 0.908 atm
Explanation:
According to Dalton's law, the total pressure is the sum of individual partial pressures. exerted by each gas alone.
= partial pressure of nitrogen = 0.256 atm
= partial pressure of helium = 203 mm Hg = 0.267 atm (760mmHg=1atm)
= partial pressure of hydrogen =39.0 kPa = 0.385 atm (1kPa=0.00987 atm)
Thus 
=0.256atm+0.267atm+0.385atm =0.908atm
Thus total pressure (in atm) inside of a vessel is 0.908
Your answer is C. its level of dissolved minerals ~A
The total mass is 10.57+6.96=17.53 g.
So, the percent by mass of magnesium is (10.57)/(17.53) * 100 = <u>60.3%</u>
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The percent by mass of oxygen is (6.96)/(17.53) * 100 = <u>39.7%</u>
