此反应中水是过量的,因此钠完全消耗.
生成的氢气的物质的量为:n(H2)=0.02/(2g/mol)
=0.01mol
2Na+2H2O=2NaOH+H2
2 :1
0.02mol 0.01mol
所以,金属钠的质量为:m(Na)=23g/mol*0.02mol=0.46g
则:m(Na2O)=0.584g-0.46g=0.124g
n(Na2O)=0.124g/(62g/mol)
=0.002mol
即:被氧化的钠的质量为:
m(Na')=23g/mol*0.002mol=
0.092g
Na2O+H2O=2NaOH
1 :2
0.002mol 0.004mol
所得氢氧化钠溶液的质量分数为:
(NaOH)%=(40g/mol*0.004mol)/(0.584g+9.436g-0.02g)
=1.6%