6H, 3S, and 12O
6 + 3 + 12 = 21
I believe 21 is your answer. I may be wrong, but I hope this helps anyways!
First, we need to get POH value & we can get it from this formula:
PH + POH = 14
when we have PH = 8.59
∴ POH = 14 - 8.59 = 5.41
then, we need to get [OH-] & we can get it using POH:
POH = -㏒[OH]
5.41 = -㏒[OH]
∴ [OH] = 3.89 x 10^-6
when Ksp = [Fe2-][OH-]^2
and when we have Ksp = 4.87 x 10^-17
so, by substitution:
4.87 x 10^-17 = [Fe2-] * (3.89 x 10 ^-6)^2
∴[Fe2-] = 3.22 x 10^-6 M
∴ above 3.22 x 10^-6 M of Fe2+ , Fe(OH)2 will precipitate
Answer:
The balanced chemical equation for the combustion of propane is: C3H8(g)+5O2(g)→3CO2(g)+4H2O(g).
hope it helps :)
Answer:
group 2
Explanation:
because they are the only alkalines earth metals on the periodic table
Answer:
a. 0.18 mol
b. 1.084 x 10²³ atoms
Explanation:
Data Given:
mass of gold (Au) = 35.12 g
a. number of moles of gold (Au) = ?
b. number of atoms of gold (Au) =?
Solution:
Part a:
To find number of moles following formula will be used
no. of moles = mass in grams / molar mass . . . . . . (1)
molar mass of gold (Au) = 197 g/mol
put values in equation 1
no. of moles = 35.12 g / 197 g/mol
no. of moles = 0.18 mol
so. number of moles of Au = 0.18 mol
_________________
Part b:
To find number of atoms following formula will be used
no. of moles = no. of atoms / Avogadro's number
Rearrange the above equation
no. of atoms = no. of moles x Avogadro's number . . . . . . . (2)
Avogadro's number = 6.022 x 10²³ atoms /mol
put values in equation 1
no. of atoms = 0.18 mol x 6.022 x 10²³
no. of atoms = 1.084 x 10²³
so.
number of atoms of Au = 1.084 x 10²³ atoms