Question

實(shí)驗(yàn)室常用鋅和稀硫酸反應(yīng)來制取氧氣．某同學(xué)取6.5g的鋅片并加入50g溶質(zhì)的質(zhì)量分?jǐn)?shù)一定的稀硫酸，恰好完全反應(yīng)，得到56.3g硫酸鋅溶液．計(jì)算：                                   

（1）生成氫氣的質(zhì)量．                                          

（2）所用稀硫酸溶質(zhì)的質(zhì)量分?jǐn)?shù)．                                

Answer 1

【考點(diǎn)】根據(jù)化學(xué)反應(yīng)方程式的計(jì)算；有關(guān)溶質(zhì)質(zhì)量分?jǐn)?shù)的簡單計(jì)算．         

【專題】溶質(zhì)質(zhì)量分?jǐn)?shù)與化學(xué)方程式相結(jié)合的計(jì)算．                     

【分析】（1）根據(jù)質(zhì)量守恒定律，反應(yīng)后減少的質(zhì)量為氫氣的質(zhì)量；          

（2）根據(jù)鋅的質(zhì)量計(jì)算出硫酸溶液中硫酸的質(zhì)量，進(jìn)而求質(zhì)量分?jǐn)?shù)．          

【解答】解：（1）根據(jù)質(zhì)量守恒定律，氫氣的質(zhì)量：6.5g+50g﹣56.3g=0.2g；          

答：生成氫氣的質(zhì)量為0.2g；                                     

（2）設(shè)硫酸溶液中硫酸的質(zhì)量為x                                 

Zn+H₂SO₄=H₂↑+ZnSO₄                                           

65   98                                                     

6.5g  x                                                     

                                                   

x=9.8g                                                      

所用稀硫酸溶質(zhì)的質(zhì)量分?jǐn)?shù)為： =19.6%．                  

答：所用稀硫酸溶質(zhì)的質(zhì)量分?jǐn)?shù)為19.6%．                          

【點(diǎn)評(píng)】本題較為容易，注意計(jì)算步驟和格式．