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Answer:</h2>
The magnesium ribbon, <u>D. It forms a material to cast the tool mark</u>.
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Explanation:</h2>
When a magnesium ribbon is burnt in the presence of oxygen it gives out strong light and heat is produced. Apart from it, it leads to the production of substance called as magnesium oxide which is formed as the product due to the reaction of magnesium with the oxygen present in the air.
Tool marks are the mark which is created by tools while using them. In order to identify or locate them castes made up of magnesium oxide is utilized. When this is pasted on the suspected area, the tool mark of the suspected tool gets pasted on it.
H2(g) +C2H4(g)→C2H6(g)
H-H +H2C =CH2→H3C-Ch3
2C -H bonds and one C-C bond are formed while enthalpy change (dH) of the reaction,
H-H: 432kJ/mol
C=C: 614kJ/mol
C-C: 413 kJ/mol
C-C: 347 kJ/mol
dH is equal to sum of the energies released during the formation of new bonds or negative sign, and sum of energies required to break old bonds or positive sign.
The bond which breaks energy is positive.
432+614 =1046kJ/mol
Formation of bond energy is negative
2(413) + 347 = 1173 kJ/mol
dH reaction is -1173 + 1046 =-127kJ/mol
<span>The particles are far apart from each other.</span>
Polar covalent bonds (because hydrogen and oxygen form polar bonds and are both nonmetals so it's covalent) and hydrogen bonds (because the water molecules are attracted to each other with partial charges, causing specific properties like surface tension).
So in my very bad drawing that I attached in case you're more a visual learner, the d- and d+ show the partial charges of hydrogen and oxygen (making it polar, as the electrons in the bond are more shifted towards oxygen, which is why oxygen has a negative sign) and the yellow dotted line show the hydrogen bonds.
Answer:
chemical symbol= Cl ( chlorine)
electrons= 17
2p electrons = 6