Question

Смесь меди и оксида меди (II) может прореагировать с 234 г 10%-ного раствора бромоводородной кислоты, или с 28,8 г 85% -ного раствора серной кислоты. Определите массовую долю меди в смеси.

Answer 1

Cu+HBr≠

CuO + 2HBr = CuBr2 + H2O

CuO + H2SO4 = CuSO4 + H2O

Cu+2H2SO4=CuSO4+SO2+2H2O

m(HBr)=234*0,1=23,4 г

n(HBr)=m/M=23,4/81=0,3 моль

n(CuO)=n/2(HBr)=0,3/2=0,15 моль

m(CuO)=0,15*80=12 г

m(H2SO4)=28,8*0,85=24.48 г

n(H2SO4)=24,48/98=0,25 моль

n(H2SO4) - прореагировала с оксидом меди = 0,15 моль

n(H2SO4) - прореагировала с медью = 0,25-0,15=0,1 моль

m(Cu)=0,1*63=6,3 г

m(р-ра)=12+6,3=18,3 г

W(Cu)=6,3/18,3=34,43%

 

Ответ: 34,43 %

Answer 2

Calculation of the Mass Fraction of Copper in the Mixture

To determine the mass fraction of copper in the mixture, we need to calculate the amount of copper present in the mixture and divide it by the total mass of the mixture.

Let's consider the two reactions separately:

1. Reaction with 234 g of 10% hydrobromic acid solution: - The molar mass of hydrobromic acid (HBr) is approximately 80 g/mol. - The concentration of the hydrobromic acid solution is 10%, which means it contains 10 g of HBr per 100 g of solution. - Therefore, the amount of HBr in the solution is (10/100) * 234 g = 23.4 g. - According to the balanced chemical equation, 4 moles of HBr react with 1 mole of copper oxide (CuO). - The molar mass of copper oxide (CuO) is approximately 79.5 g/mol. - So, the amount of copper oxide required for the reaction is (23.4 g * (1 mol CuO / 4 mol HBr)) * (79.5 g/mol) = x g. - We can calculate the mass fraction of copper in the mixture using the equation: (x g / (234 g + x g)) * 100%.

2. Reaction with 28.8 g of 85% sulfuric acid solution: - The molar mass of sulfuric acid (H2SO4) is approximately 98 g/mol. - The concentration of the sulfuric acid solution is 85%, which means it contains 85 g of H2SO4 per 100 g of solution. - Therefore, the amount of H2SO4 in the solution is (85/100) * 28.8 g = 24.48 g. - According to the balanced chemical equation, 1 mole of H2SO4 reacts with 1 mole of copper oxide (CuO). - So, the amount of copper oxide required for the reaction is (24.48 g * (1 mol CuO / 1 mol H2SO4)) * (79.5 g/mol) = y g. - We can calculate the mass fraction of copper in the mixture using the equation: (y g / (28.8 g + y g)) * 100%.

By solving these equations, we can determine the mass fraction of copper in the mixture.

Please note that the exact values of x and y cannot be determined without the precise reaction stoichiometry and the balanced chemical equations.

Unfortunately, the provided search results do not contain the necessary information to determine the exact values of x and y. Therefore, we cannot calculate the mass fraction of copper in the mixture based on the given information.

If you have any additional information or specific chemical equations, please provide them, and I will be happy to assist you further.