SCP 999 NHA BẠN

TL:

SCB 999 đúng ko?

~HT~

#Nguyetanh#

a, axit photphonic là đơn chất .PTK=3*16=48

b,chất natricacbonat là hợp chất. PTK=2*23+12+3*16=106

c, khí flo là đơn chất. PTK=2*19=38

d, đường là hợp chất. PTK=12*12+22*1+11*16=342

đường là nặng nhất, khí flo là nhẹ nhất

1. Mary is 10 years old. Julie is 8 years old.

Mary is (old)……older than………………… Julie.

2. The Alps are very high.

They are (high)……the highest………………..mountains in Europe.

3. An ocean is (large)….larger than………………………. a sea.

4. A Rolls Royce costs a lot of money. A Twingo costs less money.

A Rolls Royce is (expensive)..more expensive than.……………………….a Twingo.

5.John’s results were good. Fred’s results were very poor.

Fred’s results were (bad)…worse than.………………………. John’s.

6. This exercise is not difficult.

It’s (easy)…..easier than…………………….. I expected.

7. The weather is not good today – it’s raining.

I hope the weather will be (good)..better………………….next week.

8. People are not friendly in big cities.

They are usually (friendly)….friendlier………………in small towns.

9. In the government of a country, the President is (important)…the most important………………person.

10. People say that Chinese is (difficult)…..more difficult.………….to learn than English.

11. This test is not (difficult). as difficult………………..as it was last month.

Today is Thursday

@Cỏ

#Forever

TL

Today is Thursday

Hok tốt

#Kirito

What do you do this time yesterday ?

1.

Có \(M_{2O_2}=2.\left(16.2\right)=2.32=64g/mol\)

Có \(M_{N_2}=14.2=28g/mol\)

Tỉ lệ \(\frac{d_{2O_2}}{d_{N_2}}=\frac{M_{2O_2}}{M_{N_2}}=\frac{64}{28}=2,3\)

Mà \(2,3>1\)

Vậy \(2O_2\) nặng hơn \(N_2\) là 2,3 lần

2.

Có \(M_{5Al}=5.27=135g/mol\)

\(M_{Fe}=56.2=112g/mol\)

Tỉ lệ \(\frac{d_{5Al}}{d_{2Fe}}=\frac{M_{5Al}}{M_{2Fe}}=135=1,2\)

Mà \(1,2>1\)

Vậy 5Al nặng hơn 2Fe là 1,2 lần

dgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgx

h2 = 2 hidro , ==> h2 + v2 = 1*2 + v2

dgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgdgx

Đặt hoá trị của M là x

Theo quy tắc hoá trị, có \(x.1=I.3\rightarrow x=III\)

Vậy CTHH của Oxit kim loại M là \(M_2O_3\)

Có \(NTK_M.2+NTK_O.3=102\)

\(\rightarrow NTK_M.2+16.3=102\)

\(\rightarrow NTK_M=\frac{102-16.3}{2}==27đvC\)