First, we need to get the concentration of [NaH2PO4]:
[NaH2PO4] =( mass / molar mass ) * volume L
when we have mass NaH2PO4 = 6.6 g & molar mass = 120g/mol & V = 0.355 L
So by substitution:
[NaH2PO4] = (6.6g / 120g/mol) * 0.355 L = 0.0195 M
then, we need to get the concentration of [Na2HPO4]:
[Na2HPO4]= (mass / molar mass ) * volume L
So by substitution:
[Na2HPO4] = (8g/ 142g/mol) * 0.355 L = 0.02 M
and when Pka of the 2nd ionization of phosphoric acid = 7.21
So by substitution in the following formula, we can get the PH:
PH = Pka + ㏒[A]/[AH]
∴PH = 7.21 + ㏒[0.02]/[0.0195]
∴ PH = 7.2
Answer:
They contain atoms that combine together to form molecules. In multicellular organisms, such as animals, molecules can interact to form cells that combine to form tissues, which make up organs. ... All atoms contain protons, electrons, and neutrons.
Answer:
![[Fe^{+3}]=0.700 M](https://tex.z-dn.net/?f=%5BFe%5E%7B%2B3%7D%5D%3D0.700%20M)
![[NO_{3}^{-}]=2.10 M](https://tex.z-dn.net/?f=%5BNO_%7B3%7D%5E%7B-%7D%5D%3D2.10%20M)
Explanation:
Here, a solution of Fe(NO₃)₃ is diluted, as the total volume of the solution has increased. The formula for dilution of the compound is mathematically expressed as:

Here, C and V are the concentration and volume respectively. The numbers at the subscript denote the initial and final values. The concentration of Fe(NO₃)₃ is 1.75 M. As ferric nitrate dissociates completely in water, the initial concentration of ferric is also 1.75 M.
Solving for [Fe],
![[Fe^{+3}]=\frac{C_{1}.V_{1}}{V_{2} }](https://tex.z-dn.net/?f=%5BFe%5E%7B%2B3%7D%5D%3D%5Cfrac%7BC_%7B1%7D.V_%7B1%7D%7D%7BV_%7B2%7D%20%7D)
![[Fe^{+3}]=\frac{(1.75).(30.0)}{45.0+30.0 }](https://tex.z-dn.net/?f=%5BFe%5E%7B%2B3%7D%5D%3D%5Cfrac%7B%281.75%29.%2830.0%29%7D%7B45.0%2B30.0%20%7D)
![[Fe^{+3}]=0.700 M](https://tex.z-dn.net/?f=%5BFe%5E%7B%2B3%7D%5D%3D0.700%20M)
For [NO₃⁻],
There are three moles of nitrate is 1 mole of Fe(NO₃)₃. This means that the initial concentration of nitrate ions will be three times the concentration of ferric nitrate i.e., it will be 5.25 M.
![[NO_{3}^{-}]=\frac{C_{1}.V_{1}}{V_{2} }](https://tex.z-dn.net/?f=%5BNO_%7B3%7D%5E%7B-%7D%5D%3D%5Cfrac%7BC_%7B1%7D.V_%7B1%7D%7D%7BV_%7B2%7D%20%7D)
![[NO_{3}^{-}]=\frac{(5.25)(30.0)}{30.0+45.0 }](https://tex.z-dn.net/?f=%5BNO_%7B3%7D%5E%7B-%7D%5D%3D%5Cfrac%7B%285.25%29%2830.0%29%7D%7B30.0%2B45.0%20%7D)
![[NO_{3}^{-}]=2.10 M](https://tex.z-dn.net/?f=%5BNO_%7B3%7D%5E%7B-%7D%5D%3D2.10%20M)
The alcohol concentration of the mixed solution is 20%
Simplification :
Based on the given condition, formulate :
35% ×0.40 + 0.6 ×10% ÷{ 0.4+0.6}
Calculate the product :
Calculate the sum or difference : 
Any fraction with denominator 1 is equal to numerator : 0.2
Multiply a number to both numerator, denominator : 0.2 ×
Calculate the product or quotient : 
A fraction with denominator equals to 100 to a percentage 20%.
How do you find the concentration of a mixed solution?
In general when your are mixing two different concentrations together first calculate number of moles for each solution (n=CV ,V-in liter) then add them together it will be total moles,then concentration of mixture will be = total moles / total volume(liter).
Learn more about concentration of alcohol :
brainly.com/question/13220698
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The 1st law of thermodynamics doesn't specify that matter can be created nor destroyed, but that the total amount of energy in a closed system cannot be created nor destroyed though it can be changed from one form to another.