) When we went shopping we wanted to buy ___ new. C) something
2) I’m sorry, but I haven’t got ___ advice to give you. B) any
3) He looked at the engine but he couldn’t see ____. C) anything
4) She had ___ free time after she retired than previously. A) more
5) We usually drink ___ water in hot weather. B) a lot of
6) He wants ___ sugar in his tea. B) a little
7) Those are ___ files. A) Bill’s
8) There is ___ in our garden. A) a nest of a bird
9) This is these _____ ball. C) boys’
10) Ann had to use my ruler as she had left ___ at home. C) hers
11) The boys are with ___ mum today. C) their
12) Last Saturday we went fishing, but we didn’t catch many ___. B) fish
13) I can give you some money. ___ in my wallet. B) It is
14) Our two ___ are crying all the time. A) babies
<span>15) What do you need these ___ for? A) boxes </span>
Na2CO3 + H2SO4 = Na2SO4 + H2O + CO2
n(H2So4) = m/Mr = 160/98 = 1,633 моль
n(H2SO4) : n(Na2CO3) по условию = 1,633 : 1
по уравнению = 1 :1
значит H2SO4 была взята в избытке
n(Na2CO3) = m/Mr = 106/106 = 1 моль
n(Na2CO3) = n(CO2) = 1 моль
V(CO2) = Vm*n = 22,4*1 = 22,4 литра
Ответ: 22,4 литра
1)температура: если реакция эндотермическая , то равновесие влево
если экзотермическая вправо
2)при увеличении давлении -равновесие вправо
3)при увеличении конценрации Сl - равновесие влево
Дано:
m(MeF)=62.7г
m( осадка)=0.3моль
Найти:
Me-?
Решение:
2MeF+H2SO4(конц.)--->2HF↑ +Me2SO4
Ca(OH)2+2HF--->CaF2↓+2H2O
n(MeF)=n(HF)=2*n(CaF2)=0.6моль
M(MeF)=m(MeF)/n(MeF)
M(MeF)=62.7/0.6=104.5г/моль
M(Me)=M(MeF)-M(F)=104.5-19=85.5г/моль
Me ---> Rb
Ответ: Rb-рубидий