It's your wake-up time at 8:55,

To provide you with two correct translations:
Now is your wake-up time--8:55.
Now is 8:55,your wake-up time.

Time expression in English

Eight o'clock is the simplest, eight o'clock is: eight o'clock from eight o'clock to eight thirty, can use a word: past

The relative molecular weight of unsaturated hydrocarbons is 84, and two - CH2 - groups can be introduced into the molecules by hydrogenation reaction
A. 2 species B. 3 species C. 4 species D. 5 species

If the molecular weight is 84, if it is an alkane, according to CnH2n + 2, when n = 6, Mr = 86, it is the nearest 84 alkane. Then Mr = 84, it must be an alkene, and its composition is C6H12. Because it can be added with H2, it can not be a cycloalkane, but an alkene composed of C6H12. Then it can be analyzed according to the law of addition reaction. If two - CH2 - can be introduced through hydrogenation, its double bond position will not be at the end of carbon chain Because CH2 = ch - structure, after hydrogenation, ch3-ch2 - will be formed, and only one - CH2 - will be introduced, which is not suitable for the problem. Then the olefins with C6H12 composition and double bond not on the terminal carbon atom have the following three structures: ch3-ch = ch-ch2-ch2-ch3, ch3-ch2-ch = ch-ch2-ch3, (CH3) 2chch = ch-ch3. According to the above principle, we can also write (CH3) 2C = chch2-ch3, but also can not be hydrogenated Then two - CH2 - groups are introduced and eliminated, so there are three kinds of unsaturated hydrocarbons which can introduce two - CH2 - groups

Senior one chemistry [to solve the problem in detail (Ideas)] page 71 15 questions (1) O, n (2) M = 3
There are two kinds of gases, am and BN. It is known that 2.4 G am and 2.1 g BN contain the same number of atoms, and the ratio of the number of molecules is 2 ∶ 3. The number of protons in the nuclei of a and B is equal to the number of neutrons, and the number of electrons in the L layer of a atom is three times that of the k layer
(1) What are the element symbols of a and B?
(2) What is the value of m in am?

The number of electrons in L layer of a atom is three times that of k layer. If a atom is oxygen, B atom is nitrogen
(1) The element symbols of a and B are o and N respectively
(2) M in am is 2

It's your wake-up time at 8:55,