Answer:
Fe₃Si₇
Explanation:
In order to determine the empirical formula, we have to follow a series of steps.
Step 1: Determine the percent composition
Fe: 46.01%
Si: 53.99%
Step 2: Divide each percentage by the atomic mass of the element
Fe: 46.01/55.85 = 0.8238
Si: 53.99/28.09 = 1.922
Step 3: Divide all the numbers by the smallest one
Fe: 0.8238/0.8238 = 1
Si: 1.922/0.8238 = 2.33
Step 4: Multiply by numbers that make the coefficients whole.
Fe: 1 × 3 = 3
Si: 2.33 × 3 = 7
The empirical formula is Fe₃Si₇.
Answer:
1.7 * 10^-5
Explanation:
1- get the number of moles of PbCl2:
number of moles = mass / molar mass
number of moles = 0.45 / 278.1 = 1.618 * 10^-3 moles
2- get the concentration of Pb2+:
molarity = number of moles of solute / volume of solution in liters
molarity = (1.618 * 10^-3) / (0.1) = 0.0162 M
3- getting concentration of Cl-:
<span>PbCl2(s) <==> Pb2+(aq) + 2Cl-(aq)
</span>We can note that:
For a certain amount of Pb2+ formed, twice this amount of Cl- is formed.
This means that:
for 0.0162 M of Pb2+, 2*0.0168 = 0.0324 M of Cl- is formed
4- getting Ksp:
Ksp = [Pb2+][Cl-]²
Ksp = (0.0162)*(0.0324)²
Ksp = 1.7 * 10^-5
Hope this helps :)
C. a plane for forming a scientific hypotheses
Answer:
CH₂
Explanation:
Given parameters:
Percentage composition:
Carbon = 40.1%
Hydrogen = 6.6%
Unknown:
Empirical formula of the compound = ?
Solution:
The empirical formula of a substance is its simplest formula.
Elements Carbon Hydrogen
Percentage
Composition 40.1 6.6
Molecular mass 12 1
Number of moles 40.1/12 6.6/1
3.342 6.6
Divide through by
the smallest 3.342/3.342 6.6/3.342
1 2
So the empirical formula of the compound is CH₂
