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Fynjy0 [20]
3 years ago
14

What does Hess’s law state?

Chemistry
2 answers:
kirza4 [7]3 years ago
4 0
Hess's law states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions comprising it. In other words, the enthalpy change of a chemical reaction (the heat of reaction at constant pressure) does not depend on the pathway between the initial and final states. The law is a variation of the first law of thermodynamics and conservation of energy.
satela [25.4K]3 years ago
3 0

Answer:

C. The enthalpy of a reaction is the sum of the enthalpies of intermediate reactions.

Explanation:

The heat of any reaction  ΔH∘f  for a specific reaction is equal to the sum of the heats of reaction for any set of reactions which in sum are equivalent to the overall reaction.

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Underneath the ocean floor, methane can exist as a solid known as methane hydrate. Methane hydrate forms when large amounts of m
mezya [45]

Answer:

Methane is present in solid, liquid and gaseous form.

Explanation:

Methane hydrate is present in solid state when the hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in the deep oceans while on the other hand, methane which is present inside the earth surface in gaseous form due to non-availability of water that can combine with methane. Methane is also found in liquid form when it is cool with high pressure and low temperature.

8 0
3 years ago
An object has a mass of 180 kg and a volume of 90 m3. what is its density?
Murljashka [212]
Divide 180kg and 90m3 and your density will be 2kg/m3
8 0
3 years ago
Read 2 more answers
Your boss tells you that she needs a decision by the end of the day about the machine you want to purchase for your new operatio
Sergeu [11.5K]
Option 1 : 1900 - 1786 = 114

Option 2 : 1450 - 1300 = 150

Option 3: 1950 - 1833 = 117

Option 4: 2000 - 1822 = 178


Option 1 has the lowest energy rate so ver time would be the best deal.

4 0
4 years ago
Read 2 more answers
The photodissociation of ozone by ultraviolet light in the upper atmosphere is a first-order reaction with a rate constant of 1.
atroni [7]

Answer:

[O₃]= 8.84x10⁻⁷M  

Explanation:

<u>The photodissociation of ozone by UV light is given by:</u>

O₃ + hν → O₂ + O (1)

<u>The first-order reaction of the equation (1) is:</u>

rate = k [O_{3}] = - k \frac{\Delta [O_{3}]}{\Delta t} (2)

<em>where k: is the rate constant and Δ[O₃]/Δt: is the variation in the ozone concentration with time, and the negative sign is by the decrease in the reactant concentration </em>    

<u>We can get the following expression of the </u><u>first-order integrated law</u><u> of the reaction (1), by resolving the equation (2):</u>

[O_{3}]_{t} = [O_{3}]_{0} \cdot e^{-kt} (3)

<em>where [O₃](t): is the ozone concentration in the elapsed time and [O₃]₀: is the initial ozone concentration</em>

We can calculate the initial ozone concentration using equation (3):  

[O_{3}]_{t} = 5.0 \cdot 10^{-3}M \cdot e^{-(1.0\cdot 10^{-5}s^{-1}) (\frac{10d \cdot 24h \cdot 3600 s}{1d \cdot 1h})} = 8.84 \cdot 10^{-7}M

So, the ozone concentration after 10 days is 8.84x10⁻⁷M.

I hope it helps you!                    

3 0
4 years ago
How many protons are in oxygen's nucleus?
UkoKoshka [18]
There are eight protons in an Oxygen's nucleus.
8 0
4 years ago
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