Answer: (3) Energy is absorbed as bonds are broken, and energy is released as bonds are formed.
Explanation:
1) The equation given is H₂(g) + Cl₂(g) → 2HCl(g) + energy
2) The energy is shown in the product side, so energy is a product of the reaction, so energy is release.
But this is just the net energy of the process. You need more insight to deal with the energy changes in the reaction.
3) Chemical bonds store energy; this stored energy is the potential chemical energy of the molecules.
When a chemical reaction occurs, the first stage is to brake bonds.
Braking chemical bonds requires energy to overcome the bond energy. Braking bonds always absorbs energy.
On the other hand, forming bonds always release energy.
The neat energy of the reaction is the difference between the energy needed to break bonds and the energy released when new bonds form.
So, regardless the fact that, in the chemical equation that represents the reaction a net energy release is shown, you know that energy is absorbed as bonds are broken, and energy is released as bonds are formed (option 3).
Answer:
d
Explanation:
22.4 L is the same as 1 mol.
Diatomic nitrogen has a formula mass of 28.01 g/mol, so the answer is d.
Answer:
In percentage, the sample of C-4 remains = 0.7015 %
Explanation:
The Half life Carbon 14 = 5730 year
Where, k is rate constant
So,
The rate constant, k = 0.000120968 year⁻¹
Time = 41000 years
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
So,
![\frac {[A_t]}{[A_0]}=e^{-0.000120968\times 41000}](https://tex.z-dn.net/?f=%5Cfrac%20%7B%5BA_t%5D%7D%7B%5BA_0%5D%7D%3De%5E%7B-0.000120968%5Ctimes%2041000%7D)
![\frac {[A_t]}{[A_0]}=0.007015](https://tex.z-dn.net/?f=%5Cfrac%20%7B%5BA_t%5D%7D%7B%5BA_0%5D%7D%3D0.007015)
<u>In percentage, the sample of C-4 remains = 0.7015 %</u>
24.5 / 14 = 1.75
70 / 16 = 4.375
4.375 / 1.75 = 2.5
empirical formula = N2O5
