What does iron (iii) hydroxide decomposes into
1 answer:
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Answer:
C. 0.191 M
Explanation:
Our goal for this question, is to calculate the concentration of the HCl solution. For this, in the experiment, a solution of NaOH was used to find the moles of HCl. Therefore, our first step is to know the <u>reaction between HCl and NaOH</u>:
The "<u>titrant"</u> in this case is the NaOH solution. If we know the concentration of NaOH (0.100M) and the volume of NaOH (38.2 mL=0.0382 L), we can calculate the moles using the <u>molarity equation</u>:
Now, in the reaction, we have a <u>1:1 molar ratio</u> between HCl and NaOH (1 mol of HCl is consumed for each mole of NaOH added). Therefore we will have the same amount of moles of HCl in the solution:
If we want to calculate the molarity of the HCl solution we have to <u>divide by the litters</u> of HCl used in the experiment (20 mL= 0.02 L):
The concentration of the HCl solution is 0.191 M
I hope it helps!
Answer:
The number of moles =
The number of molecules =
Explanation:
Volume of the sphere is given by :
here, r = radius of the sphere
Radius = 3 mm
r = 3 mm
1 mm = 0.01 dm (1 millimeter = 0.001 decimeter)
3 mm = 3 x 0.01 dm = 0.03 dm
r = 0.03 dm
<em>("volume must be in dm^3 , this is the reason radius is changed into dm"</em>
<em>"this is done because 1 dm^3 = 1 liter and concentration is always measured in liters")</em>
(1 L = 1 dm3)
Now, concentration "C"=
The concentration is given by the formula :
This is also written as,
moles
One mole of the substance contain "Na"(= Avogadro number of molecules)
So, "n" mole of substance contain =( n x Na )
Molecules =
molecules