C.molecules- made up of more than one atom and can only be broken by chemical means
<u>Answer:</u> The spacing between the crystal planes is 
<u>Explanation:</u>
To calculate the spacing between the crystal planes, we use the equation given by Bragg, which is:

where,
n = order of diffraction = 2
= wavelength of the light =
(Conversion factor:
)
d = spacing between the crystal planes = ?
= angle of diffraction = 22.20°
Putting values in above equation, we get:

Hence, the spacing between the crystal planes is 
A chemical compound can be described as substance composed of atoms from more than one element held together by chemical bonds in a fixed stoichiometric proportion. A compound has different physical and chemical properties from its constituent elements.
For example : compound water is made up of H and O bonded together and it has different properties from O and H.
Thus, among the given options, the one coreectly describing a compound is
a) The atoms are bonded together, and the compound has different physical and chemical properties than the individual elements.
Answer:
Oxidation - reduction reaction which is called redox reaction.
Explanation:
The type of reaction that is a part of another type but treated separately is called Oxidation - reduction reaction.
Thus is because they usually involve 2 separate half reactions which are oxidation reactions that involve loss of electrons and then reduction equations which involve gain of electrons.
They are treated separately for example when sodium reacts with chlorine to form sodium chloride.
2Na + Cl2 = 2NaCl
Now, sodium undergoes oxidation by loosing elctrons and it's half reaction is;
2Na → 2Na^(+) + 2e^(-)
Meanwhile chlorine undergoes reduction by gaining electrons and its half reaction is;
Cl2 + 2e^(-) → 2Cl^(-)
With what? fhdvsbjnkmla,ksxbcvb nmajndvhbfjn m