Answer:
The pressure of the gas sample will be 0.954 atm.
Explanation:
Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container, when the temperature is constant. That is, if the pressure increases, the volume decreases; conversely if the pressure decreases, the volume increases.
Boyle's law is expressed mathematically as:
Pressure * Volume = constant
o P * V = k
To determine the change in pressure or volume during a transformation at constant temperature, the following is true:
P1 · V1 = P2 · V2
That is, the product between the initial pressure and the initial volume is equal to the product of the final pressure times the final volume.
In this case:
- P1= 0.609 atm
- V1= 19.9 L
- P2=?
- V2= 12.7 L
Replacing:
0.609 atm* 19.9 L= P2* 12.7 L
Solving:
P2= 0.954 atm
<u><em>The pressure of the gas sample will be 0.954 atm.</em></u>
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Answer: The enthalpy of reaction is, -206.18 kJ
Explanation:-
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The final reaction is
The intermediate balanced chemical reaction will be,
(1)
(2)
(3)
Now adding (2) and (3) and subtracting (1) , we get :
Therefore, the enthalpy of reaction is, -206.18 kJ
Object one will float because the mass and volume are lighter than object two. Object one also has a smaller surface area.
Answer:
Divergent boundary on land
Explanation:
A rift valley is a lowland region that forms where Earth’s tectonic plates move apart (diverge), or rift. Rift valleys are found both on land and at the bottom of the ocean, where they are created by the process of seafloor spreading.
Rift valleys are created by tectonic activity and not the process of erosion.
Tectonic plates are huge, rocky slabs of Earth's lithosphere—its crust and upper mantle. Tectonic plates are constantly in motion—shifting against each other in fault zones, falling beneath one another in a process called subduction, crashing against one another at convergent plate boundaries, and tearing apart from each other at divergent plate boundaries.
The most well-known rift valley on Earth is probably the so-called "Great Rift Valley System" which stretches from the Middle East in the north to Mozambique in the south. The area is geologically active, and features volcanoes, hot springs, geysers, and frequent earthquakes.
Answer:
B) 271 g.
Explanation:
- It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
- Half-life time is the time needed for the reactants to be in its half concentration.
- If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
- Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
- The half-life of As-76 = 26.0 hours.
- For, first order reactions:
<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>
Where, k is the rate constant of the reaction.
t1/2 is the half-life of the reaction.
∴ k =0.693/(t1/2) = 0.693/(26.0 hours) = 0.02665 hour⁻¹.
- Also, we have the integral law of first order reaction:
<em>kt = ln([A₀]/[A]),</em>
where, k is the rate constant of the reaction (k = 0.02665 hour⁻¹).
t is the time of the reaction (t = 538 min = 8.97 hour).
[A₀] is the initial concentration of (As-76) ([A₀] = 344 g).
[A] is the remaining concentration of (As-76) ([A] = ??? g).
∴ (0.02665 hour⁻¹)(8.97 hour) = ln((344 g)/[A])
∴ 0.239 = ln((344 g)/[A]).
- Taking exponential for both sides:
∴ 1.27 = ((344 g)/[A]).
∴ [A] = (344 g)/(1.27) = 270.88 g ≅ 271 g.
- So, the right choice is: B) 271 g.