18. <span>Answer is </span>
A<span>
<span>Since the enthalpy of reaction is positive, the
forward reaction is<span> an endothermic reaction which means the energy
is gained from the surrounding to happen the reaction. If the temperature
decreases, according to the </span></span>Le Chatelier's principle, the system tries to become equilibrium
by increasing temperature. Since forward reaction is endothermic (because of
the bond breaking), the backward reaction is exothermic (because of the bond
making) which releases the energy to the surroundings. This makes the increase
of temperature. So if the backward reaction is promoted because of the decrease
of temperature, then the concentration of H</span><span>₂ will decrease.</span>
<span>
</span>
19. Answer is A.
The reactant side
has 2 moles/molecules of reactants and the product side has 4 moles/molecules
of products which come from 1 N₂(g) and 3 H₂<span>(g). If the pressure is reduced in the system, according to the Le Chatelier's principle, the
system tries to increase the pressure. </span><span>Hence, forward
reaction is promoted because of the higher number
of molecules in product side. If the forward reaction is promoted, the
concentration of NH</span>₃(g) will decreased.
<span>20. </span>Answer is C.
If the concentration
of reactant is increased in the
system, according to the Le Chatelier's principle, the system tries
to reduce the concentration of that reactant. So if NH₃(g) concentration
is increased, then to be equilibrium, the forward reaction will be promoted.
Then the concentration of N₂<span>(g) will increase.</span>
<span> </span>
The total charge on an atom comes from protons and electrons.
The proton is positively charged while the electron is negatively charged. A neutral atom would have an equal number of protons and electrons.
An atom with more protons than electrons will be positively charged while those with more electrons than protons will be negatively charged.
More on the atom can be found here: brainly.com/question/1641336
Answer:
Seismic waves are waves of energy that travel through Earth's layers, and are a result of earthquakes, volcanic eruptions, magma movement, large landslides and large man-made explosions that give out low-frequency acoustic energy
Explanation:
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Merry Christmas
Answer:
Threatened Species: A threatened species is a species at risk but not yet endangered. California sea otters were classififed as a threatened species. Laws were passed to protect the otters and now they have increased their population size.
Invasive Species: One of the main causes of extinction and endangered species is the introduction of an exotic species. New exotic species are called invasive species. Invasive species can disrupt food chains, carry disease, prey on native species directly, and out-compete native species for limited resources, like food.
Extinction: If a population decreases too much in numbers, they disappear. Extinct species mean that the species has died out and no individuals left. An example of extinction: New Zealand was once home to a bird called the Giant Moa. Humans settled as their population increased the Moa population decreased. The species is now extinct.
Explanation:
From the calculations, the concentration of the acid is 0.24 M.
<h3>What is neutralization?</h3>
The term neutralization has to do with a reaction in which an acid and a base react to form salt and water only.
We have to use the formula;
CAVA/CBVB = NA/NB
CAVANB =CBVBNA
The equation of the reaction is; 2NaOH + H2SO4 ----> Na2SO4 + 2H2O
CA = ?
CB = 1.2 M
VA = 50 mL
VB = 20 mL
NA = 1
NB = 2
CA = CBVBNA/VANB
CA = 1.2 M * 20 mL * 1/ 50 mL * 2
CA = 0.24 M
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