<h2>
Answer:</h2>
The magnesium ribbon, <u>D. It forms a material to cast the tool mark</u>.
<h2>
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.
a. 35.8 KJ
b. 871 g
c. Fe
..........................................................................................
At stp the volume is 22.4 L .
hope this helps!
Molar mass of Calcium ( Ca ) = 40.078 g/mol
Number of moles in 9.8 grams :
1 mole Ca -----------> 40.078 g
mole Ca -------------> 9.8 g
moles Ca = 9.8 / 40.078
moles Ca = 0.2445 moles
number of molecules:
1 mole ----------------> 6.02x10²³ molecules
0.2445 moles --------> ?
= 0.2445 * 6.02x10²³
= 1.47x10²³ molecules
hope this helps!.
