A. When two chemicals mix their temperature rise: <span>Exothermic
b. </span>A solid burns brightly and releases heat, light and sound: <span>Exothermic
c. </span>When two chemicals are mixed their temperature drops: <span>Endothermic
d. </span>Two chemicals will only react if you heat them continually: <span>Endothermic
e. </span>Plants take in light energy for photosynthesis: <span>Endothermic
I hope this helps :)</span>
By using the following formula we can calculate the volume;
C₁V₁ = C₂V₂
C₁ = concentration of starting solution = 0.098m
V₁ = volume of starting solution that is needed for titration = 20.01ml
C₂ = Desired concentration of final solution = ?
V₂ = desired volume of final solution = 0.215g = 0.215ml
Now putting the values in the formula;
0.098 x 20.01 = C₂ x 0.215
C₂ = 0.215 / 1.96098 = 0.109m = 0.11m
Thus, the answer is 0.11m.
The number of covalent bonds is determined by the number of valence electrons of an element. The number of electrons tells the maximum number of bonds an element allows. In this case, an oxygen atom requires two bonds. So for Sio2, each oxygen atoms are bonded in double bonds to Si. Hence there are two covalent bonds.