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>
Answer:
Climate is long time intervals and weather is short time intervals
Explanation:
CH3OH and CH3CH2CH2OH will easily dissolve in water based on polarity not on size.
<h3>What is Polarity ?</h3>
In chemistry, polarity describes the type of bonds that exist between atoms. Atoms share electrons when they join forces to form chemical bonds. When one of the atoms applies a stronger attractive force to the bond's electrons, a polar molecule is created.
- For instance, the chlorine atom is slightly negatively charged while the hydrogen atom in hydrogen chloride is slightly positively charged.
- Water is polar due to its form even though its molecules have no net charge. The molecule's hydrogen ends are positive, and its oxygen ends are negative. Water molecules are drawn to other polar molecules and to one another as a result.
Learn more about Polarity here:
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Answer:
(a) Density of the air = 1.204 kg/m3
(b) Pressure = 93772 Pa or 0.703 mmHg
(c) Force needed to open the door = 15106 N
Explanation:
(a) The density of the air at 22 deg C and 1 atm can be calculated using the Ideal Gas Law:
First, we change the units of P to Pa and T to deg K:
Then we have
(b) To calculate the change in pressure, we use again the Ideal Gas law, expressed in another way:
(c) To calculate the force needed to open we have to multiply the difference of pressure between the inside of the freezer and the outside and the surface of the door. We also take into account that Pa = N/m2.
