What types of atoms typically form covalent bonds?
The correct answer:
d) Nonmetals with nonmetals, because their difference in electronegativity is below 1.7.
En example to explain:
An example of a covalent bonding: HCl -> 2 nonmentals
-> a difference in electronegativity less than 1.7:
EN(Cl) = 3.0 and EN (H) = 2.1 (you can search these values in a periodic table)
/\EN = 3.0 - 2.1 = 0.9
0.9 < 1.7
I hope this helped you out!
As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its 
can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.
Let the three equations with given be denoted as (1), (2), (3), and the last equation (4). Let 
, 
, and 
be letters such that 
. This relationship shall hold for all chemicals involved.
There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, 
shall resemble the number of 
left on the product side when the second equation is directly added to the third. Similarly
Thus
and
Verify this conclusion against a fourth species involved- 
for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.
Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.
What invention I want to help you but I am confused
Explanation:
it should be option number (D) Iron (III) oxide
Answer:
Nitrogen molecule is 28 neuclons×1.67×10-27 kg/nucleon = 4.68 д 10-26 kg. So the average speed of a gas molecule is about 500 m/sec. This is roughly the speed of sound in a gas 340 m/sec. So the average kinetic energy of the gas molecules is related to the temperature of the gas.
I hope this is helpful
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