According to Raoult's low:
We will use this formula: Vp(Solution) = mole fraction of solvent * Vp(solvent)
∴ mole fraction of solvent = Vp(Solu) / Vp (Solv)
when we have Vp(solu) = 25.7 torr & Vp(solv) = 31.8 torr
So by substitution:
∴ mole fraction of solvent = 25.7 / 31.8 =0.808
when we assume the moles of solute NaCl = X
and according to the mole fraction of solvent formula:
mole fraction of solvent = moles of solvent / (moles of solvent + moles of solute)
by substitute:
∴ 0.808 = 0.115 / (0.115 + X)
So X (the no.of moles of NaCl) = 0.027 m
Answer:
See explanation and picture below
Explanation:
First, in the case of methyloxirane (Also known as propilene oxide) the mechanism that is taking place there is something similar to a Sn2 mechanism. Although a Sn2 mechanism is a bimolecular substitution taking place in only step, the mechanism followed here is pretty similar after the first step.
In both cases, the H atom of the HBr goes to the oxygen in the molecule. You'll have a OH⁺ in both. However, in the case of methyloxirane the next step is a Sn2 mechanism step, the bromide ion will go to the less substitued carbon, because the methyl group is exerting a steric hindrance. Not a big one but it has a little effect there, that's why the bromide will rather go to the carbon with more hydrogens. and the final product is formed.
In the case of phenyloxirane, once the OH⁺ is formed, the next step is a Sn1 mechanism. In this case, the bond C - OH⁺ is opened on the side of the phenyl to stabilize the OH. This is because that carbon is more stable than the carbon with no phenyl. (A 3° carbon is more stable than a 2° carbon). Therefore, when this bond opens, the bromide will go there in the next step, and the final product is formed. See picture below for mechanism and products.
<span>1s2, 2s2, 2p6, 3s2, 3p6, 3d5</span>
Explanation:
The basis for classifying changes in matter into physical and chemical change is to see if a material is altered after going through a process.
In a physical change only the state of matter is usually altered especially its form or shape.
Chemical change alters a substance by producing new kinds that are totally different from it.
- In a chemical change, new kinds of matter are usually formed.
- Such changes are usually irreversible.
- Change of state is a reversible process.
learn more:
Chemical change brainly.com/question/9388643
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A chain reaction is a nuclear reaction that occurs when sufficient unstable nuclei are present so that when one splits (decays), its products hit other unstable nuclei, causing them to decay and initiating a chain reaction.
If this reaction goes uncontrolled, a massive explosion occurs. Such a reaction is the type that went uncontrolled when nuclear bombs were dropped over Hiroshima and Nagasaki in World War II. A chain reaction is much like dominoes all in a row; when one goes down, they all go down in order. The only way to block the chain reaction is to pull out a domino or to block the fall so the "chain" is broken.
The amount of fissionable material needed to accomplish a spontaneous chain reaction is called the critical mass. The critical mass for U-235 is about 1 kg. This explosive fission process takes place quickly, and an incredible amount of energy is released when it occurs.
So it would be C.
