试题与答案

铜及铜的化合物有多种应用.请回答下面相关问题: (1)下列两种方法均可以制备Cu

题型:填空题

题目:

铜及铜的化合物有多种应用.请回答下面相关问题:

(1)下列两种方法均可以制备CuSO4

①2Cu+O2

  △  
.
 
2CuO           CuO+H2SO4=CuSO4+H2O       ②Cu+2H2SO4(浓)
  △  
.
 
CuSO4+SO2↑+2H2O

假如某工厂欲生产CuSO4,请选择一种方法并说明理由______.

(2)已知铜与稀硫酸不反应,但将铜片在稀硫酸中长时间加热时溶液会呈蓝色,请用化学方程式表示原因______.

如果铜片在稀硫酸中加热时滴入几滴H2O2,溶液也会很快呈蓝色,请用离子方程式表示原因______.

(3)已知:2Cu(s)+

1
2
O2(g)=Cu2O(s);△H1=-12.0kJ/mol

2Cu(s)+S(s)=Cu2S(s);△H2=-79.5kJ/mol

S(s)+O2 (g)=SO2(g);△H3=-296.83kJ/mol

求 Cu2S(s)+2Cu2O(s)=6Cu(s)+SO2(g);△H4=______kJ/mol

(4)某黑色固体据分析由Cu2S和CuS组成.

已知 Cu2S可以和硝酸反应,请配平下列化学反应方程式:□Cu2S+□HNO3

  △  
.
 
□CuSO4+□Cu(NO32+□NO↑+□______

化学兴趣小组同学欲分析黑色固体的成分,设计了如下实验方案:先称取样品m1g,然后充分加热反应后测得生成CuO质量为m2g,则样品中含Cu2S______g.

答案:

(1)方法①中Cu、H2SO4的利用率100%,且无污染,方法②中Cu的利用率100%,H2SO4的利用率50%,且产生污染物,故答案:选择方法①原料利用率高,污染少;

(2)因溶液中有氧气,加热能与铜反应生成氧化铜:2Cu+O2

 加热 
.
 
2CuO,氧化铜再与硫酸反应:CuO+H2SO4=CuSO4+H2O,两式相加:2Cu+O2+2H2SO4
  △  
.
 
2CuSO4+2H2O,因加热时滴入几滴

H2O2,溶液也会很快呈蓝色,说明H2O2能讲铜氧化成铜离子,离子反应为Cu+H2O2+2H+

  △  
.
 
Cu2++2H2O,故答案:2Cu+O2+2H2SO4
  △  
.
 
2CuSO4+2H2O;Cu+H2O2+2H+
  △  
.
 
Cu2++2H2O;    

(3)已知:2Cu(s)+

1
2
O2(g)=Cu2O(s);△H1=-12.0kJ/mol      ①

              2Cu(s)+S(s)=Cu2S(s);△H2=-79.5kJ/mol      ②

               S(s)+O2 (g)=SO2(g);△H3=-296.83kJ/mol    ③

根据盖斯定律③-①×2-②可得Cu2S(s)+2Cu2O(s)=6Cu(s)+SO2(g);△H4=-193.33kJ/mol,

故答案为:-193.33;

(4)根据化合价升降总数相等可知,

                Cu2S    Cu:+1→+2↑2     共↑10×3

                         S:-2→+6↑8    

                HNO3 N:+5→+2↓3×10      

则配平后的化学反应为3Cu2S+16HNO3

  △  
.
 
3CuSO4+3Cu(NO32+10NO↑+8H2O,

故答案:3,16,3,3,10,8H2O;

(5)设Cu2S 的质量为x,CuS 的质量为y,

            Cu2S~2CuO                 CuS~CuO

         160         160             96         80

          x           x              y         

5
6
 y  

建立方程组:

x+y=m1
x+
5
6
y=m2

解得:x=6m2-5m1,y=6m1-6m2

故答案为:6m2-5m1

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For most of the day construction worker Sidney Smith and his brother – in – law Joseph Chambers had been   21  along the banks of Lake Waco with little   22 . Chambers suggested they go home, but Smith 33  that there were still several hours of daylight 24  and there was one other place they might try a bit longer before  25 .
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