Question

1.Calculați numărul de molecule continut in 2 grame de apă (6,7 10²² molecule). 2.Cate molecule conțin 20 de g de O2? (3,7 10²³). Cu rezolvări. Cine nu stie sa nu răspundă,altfel dau raport.​

Answer 1

[tex]1.N_A=6,022*10^{23} molecule*mol^{-1}\\m_{H_2O}=2 g=0,002 kg\\ \mu_{H_2O}=2*1+16=18 g/mol=0,018 kg/mol\\\nu=\frac{m_{H_2O}}{\mu_{H_2O}}=\frac{0,002}{0,018}=0,11 moli\\ N=\nu N_A=0,11*6,022*10^{23}=0,6691*10^{23}molecule=6,691*10^{22} molecule [/tex]

[tex]2. m_{O_2}=20 g=0,02 kg\\ \mu_{O_2}=2*16=32 g/mol=0,032 kg/mol\\\nu=\frac{m_{O_2}}{\mu_{O_2}}=\frac{0,02}{0,032}=0,625 moli\\ N=\nu N_A=0,625*6,022*10^{23}=3,76*10^{23} molecule [/tex]