In the series, the serf tells the story of the life of an eighteen-year-old girl Catherine. From birth, she was a serf but was brought up as a real court lady. Katerina was educated, but the most important thing for Katya was not freedom. Once in the life of Katya, a beautiful nobleman Alexei appears. At first glance, she fell in love with him. But unfortunately Alexey died. After that, Katerina started having problems. In this series two worlds are shown. The poor and the rich. This is a melodrama In which the main characters Katya Kovalchuk, Alexei Yarovenko, Olga Sumskaya, Mark Drobot, Olesya Zhurakovskaya, Stanislav Boklan. The director of the melodrama is Felix Gerchikov. This is a very interesting series for both teenagers and adults, very mesmerizing and impressive!
Б3
В1
Г4
8. I валентність, Калій оксид
III валентність, фосфор 3 оксид
IV валентність, нітроген 4 оксид
VI валентність, сульфур 6 оксид
9. C+O2=CO2
4Al+3O2=2Al2O3
10. Fe2O3
w(Fe)*2/Mr(Fe2O3)*100%
Mr(Fe2O3)=56*2+3*16=160
Ar(Fe)=56
w(Fe)=56*2/160*100%=112/160*100%=0,7*100%=70%
w(O)=100%-w(Fe)=100%-70%=30%
Відповідь: 30%
11. Mr(K3PO4)=39*3+31+16*4=117+31+64=212
12. Дано:
m(води)=240г |
m(цукру)=65г |
|
w(цукру)=?
Розв'язання:
m(розчину)=m(води)+m(цукру)=240+64=305г
w(цукру)=m(цукру)/m(розчину)*100%=65/305*100%=0,2*100%=20%
m вещества(NaOH)=m раствора(NaOH)*w(NaOH)/100%=200*15/100=30 г.
n(NaOH)=m(NaOH)/M(NaOH)=30/40=0.75 моль
n(H2O)=n(NaOH)=0.75 моль.
ответ: 0.75 моль.