Answer:
B
Explanation:
placenta comes after baby
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!.
<span>1. Tap water has a small concentration of H+ & OH- ions as well as water molecules, hence there would be permanent dipole-permanent dipole (p.d.-p.d.) forces of attraction between the water molecules (aka H-bonds) as well as ionic bonds between the H+ & OH- ions.
2. Distilled water does not have H+ & OH- ions, hence only H-bonds exist between the water molecules.
3. There are covalent bonds between the individual sugar molecules.
4. There are ionic bonds between the Na+ & Cl- ions in NaCl.
5. There are p.d.-p.d. forces of attraction between the Na+ ions and the O2- partial ions of the water molecules as well as between the Cl- ions and the H+ partial ions of the water molecules. There are also H-bonds between the individual water molecules and ionic bonds between the Na+ & Cl- ions (although these are in much lower abundance than in unsolvated solid NaCl).
6. There are i.d.-i.d. as well as p.d.-p.d. forces of attraction between the sugar molecules and the water molecules. There are also H-bonds between the individual water molecules and covalent bonds within the sugar molecules.</span>
Answer:
13. Index Fossils
14. Index Fossils
15. C
16. Geologists use index fossils to define geological periods.
17. C
18. A
