mixture Mg Zn 1.0875 g MgO ZnO 1.4090 g

A mixture of Mg and Zn with a combined mass of 1.0875 g was burned in oxygen, producing MgO and ZnO with a combined mass of 1.4090 g. How many grams of zinc was in the original mixture?

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Mg + Zn = 1.0875 g 이므로,

Zn의 질량(g) = x 라 두면,

Mg의 질량(g) = (1.0875 – x)

> Zn의 몰질량 = 65.38 g/mol

> ZnO의 몰질량 = 81.38 g/mol

> 2Zn + O2 → 2ZnO

---> Zn : ZnO = 1 : 1 계수비(= 몰수비)

---> Zn의 몰수만큼, ZnO가 생성된다.

(x g Zn) / (65.38 g/mol Zn) × (81.38 g/mol ZnO)

= 1.2447x g ZnO

( 참고: n=W/M https://ywpop.tistory.com/7738 )

> Mg의 몰질량 = 24.31 g/mol

> MgO의 몰질량 = 40.30 g/mol

> 2Mg + O2 → 2MgO

---> Mg : MgO = 1 : 1 계수비(= 몰수비)

---> Mg의 몰수만큼, MgO가 생성된다.

(1.0875 – x Mg) / (24.31 g/mol Mg) × (40.30 g/mol MgO)

= (1.0875 – x) / (24.31) × (40.30)

= (1.8028 – 1.6578x) g MgO

ZnO + MgO = 1.4090 g 이므로,

1.2447x + (1.8028 – 1.6578x) = 1.4090

0.4131x = 0.3938

x = 0.3938 / 0.4131

= 0.9533 g

---> Zn의 질량

답: 0.9533 g

[키워드] Mg Zn 혼합물 기준

mixture Mg Zn 1.0875 g MgO ZnO 1.4090 g