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a) Canxi oxit + Nước −−−−> Canxi hidroxit
b) Photpho + Oxi −−to−−> Điphotpho pentaoxit
c) Kali clorat −−to−−> Kali clorua + Oxi
d) Kẽm + Axit clohidric −−−−−−> Kẽm clorua + Hidro
e) Canxi cacbonat + Axit sunfuric −−−−−−> Canxi sunfat + Cacbon đioxit + Nước
a) Gọi công thức của X là CxHyOz
Ta có: mC = (13,44 . 12)/22,4 = 7,2 (gam); mH = 9.2/18 = 1 (gam)
MO = 16,2 – 7,2 = 8 (gam)
=>x : y : z = 7,2/12 : 1/1 : 8/16 = 0,6 : 1 : 0,5 = 6 : 10 : 5
Vậy CTPT của X là (C6H10O5), X là polisaccarit.
b) (C6H10O5)n+ nH2O→H+ nC6H12O6.
1 mol n mol
16,2/162n mol a mol
=>a = 0,1 mol
C5H11O5CH=O + 2AgNO3 + 3NH3 + H2O → C5H11O5COONH4 + 2Ag ↓ + 2NH4NO3.
Theo phương trình, ta có: nAg = 0,2 mol
Vì hiệu suất phản ứng bằng 80% =>mAg = (0,2 . 108.80)/100 = 17,28 (gam)
1. We used to go to school on foot.
2. It's about 30 km from my town to a Long Bay.
3. My family used to go on holiday at the seaside in the summer.
4. How long does it take you to go from Hanoi to Sapa.
5. There used to be a factory in the town centre but it had been moved to the suburbs.
6. You must learn about road safety before riding your bike on the road.
1. We used to go to school on foot.
2. It's about 30 km from my town to Hạ Long Bay.
3. My family used to go on holiday to the seaside in the summer.
4. How long does it take you to go from Hanoi to Sapa.
5. There used to be a factory in the town centre but it had been moved to the suburbs.
6. You must learn about road safety before riding your bike on the road.
1. We must be quick. There’s …………time left. A. little B. few C. much D. more
2. He made the soup by mixing ………… meat with some rice. A. little B. few C. a little D. a few
3. Luckily, I ………few mistakes in my last exam. A. make B. made C. have made D. am making
4. You look very …………. I’m sure you play sports regularly. A. thin B. fat C. fit D. well
5. Hamlet is an example of a ……. It has an unhappy ending. A. tragedy B. character C. comedy D. play
6. I …………such nice and enthusias volunteers before.
A. never meet B. have never met C. never met D. will never meet
7. I want to pass the test, …………I’m studying hard. A. but B. because C. so D. although
8. Paul is similar to his brother in their interest ………horse riding. A. to B. with C. for D. in
9. I am not ready yet and …………A. she is too B. she is not C. so is she D. she isn’t either
10. They play was very long, but there were two……… A. intervals B. rests C. interruptions D. gaps
……………………………………………………………………………………….
1. The wheel was invented thousand of years ago.
2. Are the statue of Chu Van An being built (by them)?
3. Is Temple of Literature surrounded by four busy streets?
4. Pencils are not provided at the test, so please bring your own.
5.We hasn't been taught by Mr. Binh since the last semester.
6. That experiment is being done by a student teacher.
7. Was this dictionary bought (by you) two weeks ago?
8. I'm not impressed with Alan's knowledge about science and technology.
9. A new school is going to be built here next year (by them).
10. This computer have been used for two years (by me).
Kali có nguyên tử khối là 39 và hóa trị là I.
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