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:
20 moles
Explanation:
4 Fe + 3O₂ → Fe₂O₃
The chemical equation provided is not yet balanced so let's start by balancing it.
4 Fe + 3O₂ → 2 Fe₂O₃
The equation is now balanced with 4 Fe atoms and 6 O atoms on both sides of the equation. It is important to ensure that the chemical equation is balanced, as only then will it tell you the relationship of the reactants and products in terms of mole.
Looking at the coefficients of Fe and Fe₂O₃, 4 moles of Fe is needed to make 2 moles of Fe₂O₃.
This can be simplified into the mole ratio below.
Fe: Fe₂O₃= 2: 1
This means that for every mole of Fe₂O₃, twice the amount of Fe (in moles) is needed.
Thus for 10 moles of Fe₂O₃,
amount of Fe needed
= 10 ×2
= 20 moles
Answer:
240 seconds
Explanation:
Data Given:
Distance Radio travel to earth = 7.19 ×10⁷ km
Speed of this radio signal = 3.00 ×10⁸ m/s
Solution:
First convert Km to m
1 km = 1000 m
7.19 ×10⁷ km = 7.19 ×10⁷ x 1000 = 7.19 × 10¹⁰m
Formula used to calculate time
Speed (S) = distance (d) / time (t)
rearrange above equation for time
time (t) = distance (d) / Speed (S) . . . . . . . . .(1)
Put values in equation 1
time (t) = 7.19 × 10¹⁰/ 3.00 ×10⁸ m/s
time (t) = 240 s
So 240 seconds it take for the signal to reach the earth
Answer:
b
Explanation:
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