sodium metal reacts completely with water. 25.0℃ 246 mL 1.00 atm

sodium metal reacts completely with water. 25.0℃ 246 mL 1.00 atm

 

 

A piece of sodium metal reacts completely with water as follows:

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

The hydrogen gas generated is collected over water at 25.0℃.

The volume of the gas is 246 mL measured at 1.00 atm.

Calculate the number of grams of sodium used in the reaction.

(Vapor pressure of water at 25℃ = 0.0313 atm.)

 

 

 

H2의 압력 = 1.00 – 0.0313 = 0.9687 atm

( 참고: 수상포집 https://ywpop.tistory.com/3490 )

 

 

 

PV = nRT 로부터,

( 참고 https://ywpop.tistory.com/3097 )

 

H2의 몰수를 계산하면,

n = PV / RT

= [(0.9687) (0.246)] / [(0.08206) (273.15+25)]

= 0.00974 mol H2

 

 

 

2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

 

Na : H2 = 2 : 1 계수비(= 몰수비) 이므로,

0.00974 mol H2 생성 시 반응한 Na의 몰수를 계산하면,

Na : H2 = 2 : 1 = ? mol : 0.00974 mol

 

? = 2 × 0.00974 = 0.0195 mol Na

 

 

 

Na의 몰질량 = 22.99 g/mol 이므로,

0.0195 mol Na의 질량을 계산하면,

0.0195 mol × (22.99 g/mol) = 0.448 g Na

 

 

 

답: 0.448 g

 

 

 

 

[키워드] Na metal H2 gas 25.0℃ 1.00 atm 246 mL Na mass water vapor 0.0313 atm, 수상포집 기준

 

[FAQ] [①22/06/17] [②24/04/05]