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13 tháng 2 2022

gfvfvfvfvfvfvfv555

27 tháng 3 2021

c.phi vitamin đạo đức và về nhà

27 tháng 3 2021

uk,chỉ còn 4 người nữa thôi,nhanh lên !

14 tháng 4 2021

PTHH:

\(CH=CH+2Br_2\rightarrow CHBr_2-CHBr_2\)

\(n_{Br_2}=0,2mol\)

\(\rightarrow n_{C_2H_2}=\frac{0,2}{2}=0,1mol\)

\(\rightarrow V=0,1.22,4=2,24l\)

=> Chọn A. 2,24l

13 tháng 4 2021

Phản ứng xảy ra:

\(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

Khí thoát ra là \(CH_4\)

\(CH_4+2O_2\rightarrow^{t^o}CO_2+2H_2O\)

\(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

\(\rightarrow n_{CaCO_3}=\frac{40}{100}=0,4mol=n_{CO}_{_2}=n_{CH_4}\)

\(\rightarrow V_{CO_2}=0,4.22,4=8,96l\)

\(\rightarrow\%V_{CH_4}=\frac{8,96}{13,56}=66\%\rightarrow\%V_{C_2H_4}=34\%\)

Trả lời :

Chọn B bạn nhé

OK.

PTHH:

\(CO_2+Ca\left(OH\right)_2\rightarrow CACO_3+H_2O\)

Khí còn lại bay ra là khí \(CH_4\rightarrow CH_4\)được làm sạch

=> Chọn A. Dung dịch Ca(OH)\(_2\)

20 tháng 4 2021

Cho hỗn hợp qua dung dịch brom dư

\(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

Khí thoát ra là \(CH_4\)

\(CH_4+2O_2\rightarrow^{t^o}CO_2+2H_2O\)

\(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)

Ta có:

\(n_{CaCO_3}=\frac{40}{100}=0,4mol=n_{CO_2}=n_{CH_4}\)

\(\rightarrow V_{CH_4}=0,4.22,4=8,96l\)

\(\rightarrow\%V_{CH_4}=\frac{8,96}{13,56}=66\%\rightarrow\%V_{C_2H_4}=34\%\)

7 tháng 2 2022

\(\%m_{C\left(CH_4\right)}=\frac{12}{12+4}.100\%=75\%\)

\(\%m_{C\left(C_2H_4\right)}=\frac{12.2}{12.2+4}.100\%\approx85,71\%\)

\(\%m_{C\left(C_2H_2\right)}=\frac{12.2}{12.2+2}.100\%\approx92,31\%\)

\(\%m_{C\left(C_2H_3OH\right)}=\frac{12.2}{12.2+4+16}.100\%\approx54,55\%\)

Vậy \(C_2H_2\) có %C lớn nhất.

I.CHOOSE THE WORD WHOSE UNDELINED PART IS PRONOUNCED DIFFERENTLY FROM THAT OF THE OTHERS1.A. sauce              B.steam              C.sugar            D.stew2.A.tender              B.garnish            C.drain             Dsprinkle.3.A.grill                  B.garnish            C.dip                 D.slice4.A.checkout         B.erode               C.exotic            D.decision5.A.establish         B.erode              C.resort            D.expeditionII. CHOOSE THE WORD WHOSE MAIN STRESS...
Đọc tiếp

I.CHOOSE THE WORD WHOSE UNDELINED PART IS PRONOUNCED DIFFERENTLY FROM THAT OF THE OTHERS
1.A. sauce              B.steam              C.sugar            D.stew
2.A.tender              B.garnish            C.drain             Dsprinkle.
3.A.grill                  B.garnish            C.dip                 D.slice
4.A.checkout         B.erode               C.exotic            D.decision
5.A.establish         B.erode              C.resort            D.expedition
II. CHOOSE THE WORD WHOSE MAIN STRESS POSITION IS PLACED DIFFERENTLY FROM THAT OF THE OTHERS
1.A.magnificence         B.destination            C.affordable              D.accessible
2.A.original                  B.stimulating             C.imperial                 D.geograhy
3.A.provide                  B.bilingual                C.immersion              D.rusty
4.A.simplicity               B.American              C.obedient                 D.flexible
5.A.magnificity            B.destination            C.affordable               D.accessible
III.GIVE THE CORRECT FORM OF THE WORDS IN THE BRACKET:
1.If you press ''CTRL + S'', you (save).............................. the file.
2.If he (want)............................... to eat the vegetables raw, he mush them carefully.
3.She will forget to pick you up if you (not phone)................................... her.
4The (simple)........................................ of form makes english easy to learn.
5.If he (study)...................................... harder he can pass an exam
6.If you could speak english, they (will offer)............................ yoi the job.
7.I will remember you if you (give)............................ me a photo.
8.I also appreciate the invitation, our friends (open)............................shown during the interviews. 
9.If we send an invtation, our friends (come)...............................................to our party.
10. He might get fat if he (stop)......................................... to our party.
IV. put a/an/one/the in the blanks to complete the passage.
This is true story about(1)........................man who chose (2)..........................worst possible time for his crime.lt happened in London in (3)....................... summer of 1972. (4) ................... man stole a barge on (5)............................. River Thames(in case you don't know,(6) .............................. barge is a river boat used for carrying goods).(7)......................... owner of (8).................. barge soon discovered that it was missing and immediately informed (9) ................ police so that they could look for it. Normally (10)............ puite(11)....................... busy place,and it would be difficult to find what you were looking for. On this day, however, there was (12)................ dock strike, and so there was only(13) ................. barge on(13)............. barge on (14).................. river.(15)...................thief was puickly found and arrested.

1
5 tháng 2 2022

gfvfvfvfvfvfvfv555

24 tháng 3 2021

wtf, hỏi lịch sử mà tiêu đề là hóa học!

24 tháng 3 2021

vua lê uy mục