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26 tháng 2 2022
Câu 3:
Gọi số mol C2H4, C2H2 là a, b (mol)
=> \(a+b=\dfrac{6,72}{22,4}=0,3\left(mol\right)\) (1)
\(n_{Br_2}=\dfrac{64}{160}=0,4\left(mol\right)\)
PTHH: C2H4 + Br2 --> C2H4Br2
a--->a
C2H2 + 2Br2 --> C2H2Br4
b---->2b
=> a + 2b = 0,4 (2)
(1)(2) => a = 0,2; b = 0,1
=> \(\left\{{}\begin{matrix}\%V_{C_2H_4}=\dfrac{0,2}{0,3}.100\%=66,67\%\\\%V_{C_2H_2}=\dfrac{0,1}{0,3}.100\%=33,33\%\end{matrix}\right.\)
26 tháng 2 2022
Câu 4:
Chỉ có Propin pư với AgNO3/NH3
\(n_{C_3H_3Ag}=\dfrac{44,1}{147}=0,3\left(mol\right)\)
=> \(n_{C_3H_4}=0,3\left(mol\right)\)
=> \(n_{C_4H_6}=\dfrac{17,4-0,3.40}{54}=0,1\left(mol\right)\)
=> \(\left\{{}\begin{matrix}\%V_{C_3H_4}=\dfrac{0,3}{0,3+0,1}.100\%=75\%\\\%V_{C_4H_6}=\dfrac{0,1}{0,3+0,1}.100\%=25\%\end{matrix}\right.\)
mn ơi giúp mình gấp câu 3 với ạ T^T
DT
Đỗ Thanh Hải
CTVVIP
9 tháng 8 2021
1 you are => are you
2 fiveteen => fifteen
3 are => is
4 am => are
5 is => bỏ
6 thanks => thank
7 year => years
8 are => is
9 phong is => is phong
10 is => are
LT
8 tháng 5 2022
1.The man..........who............... visited our school yesterday is a famous artist
2.The girl...................who........... is standing over there is my younger sister
3.Mary works for a company.............which......... makes toys for children
4.The supermarket...........which..............was destroyd in the fire has now been rebuilt
5.The bus..........which..........runs every twenty minutes goes to Tan son nhat airport
6.An architect is someone......who.......designs buildings
7.I don't like people........who.............. often tell lies
8.Alexander bell was the man..............who.................invented the telephone
9.The sun...............................which....................is one of millions of stars in the universe provides us with heat light
10.The book............................which................................you borrowed yesterday is a present from my uncle on my 15t cemtury
8 tháng 5 2022
1.who
2.who
3.which
4.which
5.which
6.who
7.who
8.who
9.which
10.which
HV
0
TC
25 tháng 3 2022
a)\(=>x=\left(-\dfrac{1}{2}+\dfrac{1}{4}\right):2=-\dfrac{1}{8}\)
O
25 tháng 3 2022
a) \(2x-\dfrac{1}{4}=\dfrac{-1}{2}\)
\(2x=\dfrac{-1}{2}+\dfrac{1}{4}\)
\(2x=-\dfrac{1}{4}\)
\(x=-\dfrac{1}{4}\div2\)
\(x=-\dfrac{1}{8}\)
b) \(\dfrac{13}{3}-\dfrac{1}{3}\cdot\left(x+1\right)=\dfrac{4}{3}\)
\(\dfrac{1}{3}\cdot\left(x+1\right)=\dfrac{13}{3}-\dfrac{4}{3}\)
\(\dfrac{1}{3}\cdot\left(x+1\right)=3\)
\(x+1=3\div\dfrac{1}{3}\)
\(x+1=9\)
\(x=9-1\)
\(x=8\)