Tough question, I would suggest using Google maybe, or just plain out asking your science teacher.
Answer:
We need 375 milliliters of 0.100 M NaHCO3 solution
Explanation:
Step 1: Data given
Initial molarity NaHCO3 = 0.100 M
Volume prepared solution = 750.0 mL
Molarity prepared solution = 0.05 M
Step 2: Calculate initial volume
C1*V1 = C2V2
⇒with C1 = the initial concentration = 0.100 M
⇒with V1 = The initial volume = TO BE DETERMINED
⇒with C2 = the new concentration = 0.0500M
⇒with v2 = the new volume = 750.0 mL = 0.750 L
0.100 M * V1 = 0.0500 M * 0.750 L
V1 = (0.0500M * 0.750L)/0.100 M
V1 = 0.375 L = 375 mL
We need 375 milliliters of 0.100 M NaHCO3 solution
Answer:
a) CaF₂.
b) 7.81g of CaF₂ are present.
Explanation:
a) The calcium ion has as charge Ca²⁺ and fluoride ion is F⁻, that means formula unit is:
CaF₂
b) 1 molecule of CaF₂ contains 2 anions, F⁻. Thus, the moles of CaF₂ is:
1.2x10²³ anions * (1 moleculeCaF₂ / 2 anions) = 6x10²² molecules of CaF₂
6.022x10²³ molecules = 1mol:
6x10²² molecules of CaF₂ * (1mol / 6.022x10²³molecules) = 0.10 moles CaF₂.
1 mole of CaF₂ has a mass of 78.07g:
0.10 moles CaF₂ * (78.07g / mol) =
7.81g of CaF₂ are present
They both have 1 electron in their valence shell.....