(1)由质量守恒定律可知:产生的H2的质量为10g+50g-59.9g=0.1g;(2)设锌的质量为xZn+H2SO4═ZnSO4+H2↑65 2x 0.1g 65 x = 2 0.1g 解得x=3.25g 10g?3.25g 10g ×100%=67.5%故答案为:(1)0.1g;(2)黄铜中铜的质量分数67.5%.