Answer:
There is one single covalent bond between two carbon atoms.
Explanation:
We know that sharing of electrons form covalent bonds.
If we look upon K,L,M ,N shells of the carbon and hydrogen atoms.
We found that Hydrogen is having only
electron in K shell.
And Carbon on the other hand is having
electrons in K shell and
electrons in L shell.
So carbon have
valence electrons,and it can share
bonds with any relevant atom to complete its octet.
And Hydrogen requires
electron to complete its doublet.
Alkane general formula 
For ethane 

Carbon atom is shared by
Hydrogen.
The remaining one electron
of carbon will be shared with another carbon atom.
An image of the sharing of electrons attached below,
Hence we have only
covalent bond between the two.
Answer:
High pressure and low temperature.
Explanation:
Answer:
Because it will allow a bigger temperature change.
Explanation:
The specific heat of the metal can be calculated by the heat change between it and the water. The total amount of heat must be 0, thus, the heat of the metal (Qm) plus the heat of water (Qw):
Qm + Qw = 0
The heat is the mass multiplied by the specific heat (c) and by the temperature change:
mm*cm*ΔTm + mw*cw*ΔTw = 0
mm*cm*ΔTm = - mw*cw*ΔTw
So, as higher is the value of mw, as low is the value of ΔTw, and if ΔTw is very low, and so the calculations may not be precise.
Answer:
A. 
B. 
Explanation:
Hello!
In this case, since the undergoing chemical reaction between nitrogen and hydrogen is:

Thus we proceed as follows:
A. Here, we first need to compute the moles of ammonia yielded by each reactant, in order to identify the limiting one:

Thus, since nitrogen yields the fewest moles of ammonia, we realize it is the limiting reactant, so the theoretical yield, in grams, of ammonia is:

B. Finally, since the actual yield of ammonia is 1.23, the percent yield turns out:

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