Answer:

Explanation:
We have the reactions:
A: 
B: 
Our <u>target reaction</u> is:

We have
as a reactive in the target reaction and
is present in A reaction but in the products side. So we have to<u> flip reaction A</u>.
A: 
Then if we add reactions A and B we can obtain the target reaction, so:
A: 
B: 
For the <u>final Kc value</u>, we have to keep in mind that when we have to <u>add chemical reactions</u> the total Kc value would be the <u>multiplication</u> of the Kc values in the previous reactions.


It's letter C. When ever you read "breaks down" always think decomposition. When you read that compound get together to form "a single" compound, think synthesis.
Alkanes are saturated hydrocarbon that contains only single bonds, whereas Alkenes and Alkynes are unsaturated hydrocarbons which contain one or more double bond and triple bonds.
<u>Explanation:</u>
- A saturated hydrocarbon with an only single bond is called alkanes. Ethane consisting of two carbon atoms that are bonded with a single bond and six hydrogen atoms sharing the other valence electron of carbon atoms. The molecular structure of alkane is CnH2n+2.
- An unsaturated hydrocarbon with a two bond is called alkenes. Ethene consisting of two carbon atoms double-bonded to each other. The molecular structure of alkene is CnH2n.
- An unsaturated hydrocarbon with a triple bond is called as alkynes. It involves sharing three pairs of electrons. The molecular structure of alkyne is CnH2n-2.
Answer:
The correct answer is:
<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>
Explanation:
The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.