The correct options are as follows:
1. A.
A synthesis reaction is a type of reaction in which two or more reactants combine together to form only one product. Synthesis reaction always release energy in form of light and heat, therefore, they are usually exothermic reactions. In the option given in A, nitrogen and nitrogen combine together to form ammonia; this is a synthesis reaction.
2. D
A radioactive half life refers to the amount of time it will take for half of an original radioactive isotope to decay.
In the question given above, the half life of the element is 1000. Thus, in 1000 years only half of the original amount will remain. In another 1000 years only 1/4 of the original amount will remain and in another 1000 years only 1/8 of the original amount will remain. Therefore, it will take 3 half lives before 1/8 of the original sample remain.

6 0

4 years ago

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Please hurry!!! And help!!

11Alexandr11 [23.1K]

Answer:

Explanation:

5 0

3 years ago

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The strength of a covalent bond depends upon the size of the atoms and the bond order. In general short bonds are strong bonds.1

Oksana_A [137]

Answer:

Bond energy of (A) C≡C > (B) C=C

and, (C) C=N > (D) C-N

Explanation:

Bond energy refers to the amount of energy required to break a bond or the energy released when a bond is formed. Bond energy of a covalent bond suggests the bond strength of the chemical bond and depends on the bond length and bond order of the chemical bond.

The bond energy of a chemical bond increases with the bond order and decreases with the bond length. As, length of a bond decreases with increase in the bond order.

First pair: (A) C≡C (B) C=C

The bond order of C≡C - 3, the bond order of C=C - 2

Since the bond order: C≡C > C=C

Bond length: C≡C < C=C

Therefore, bond energy of (A) C≡C > (B) C=C

Second pair: (C) C=N (D) C-N

The bond order of C=N - 2, the bond order of C-N - 1

Since the bond order: C=N > C-N

Bond length: C=N < C-N

Therefore, bond energy of (C) C=N > (D) C-N

8 0

4 years ago