2.196 g Cu excess S SO2 gas 2.748 g 5.6 g/cm3

2.196 g Cu excess S SO2 gas 2.748 g 5.6 g/cm3

 

 

A copper wire having a mass of 2.196 g

was allowed to react with an excess of sulfur.

The excess sulfur was then burned, yielding SO2 gas.

The mass of the copper sulfide produced was 2.748 g.

a) What is the percent composition of copper sulfide?

b) What is its empirical formula?

c) Calculate the number of copper ions per cubic centimeter

if the density of the copper sulfide is 5.6 g/cm3.

 

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a) What is the percent composition of copper sulfide?

 

(2.196 g / 2.748 g) × 100 = 79.91% Cu

100 – 79.91 = 20.09% S

 

 

 

 

b) What is its empirical formula?

 

각 성분의 몰수를 계산하면,

79.91 g / (63.55 g/mol) = 1.257 mol Cu

( 참고 https://ywpop.tistory.com/7738 )

 

20.09 / 32.07 = 0.6264 mol S

 

 

몰수의 가장 작은 정수비를 계산하면,

Cu : S = 1.257 : 0.6264

= 1.257/0.6264 : 0.6264/0.6264

≒ 2 : 1

---> 실험식 = Cu2S

---> 실험식량 = 2(63.55) + (32.07) = 159.17 g/mol

 

 

 

 

c) Calculate the number of copper ions per cubic centimeter

if the density of the copper sulfide is 5.6 g/cm3.

 

5.6 g / (159.17 g/mol) = 0.03518 mol Cu2S

 

 

2 × 0.03518 mol × (6.022×10^23 /mol)

= 2 × 0.03518 × (6.022×10^23)

= 4.2×10^22 Cu^+ ions

 

 

 

 

[키워드] 황화구리의 조성 백분율 기준문서, 황화구리의 실험식 기준문서