The properties of a substance are not affected by chemical reactions.<br> O True<br> O False

A solution contains 0.0440 M Ca2 and 0.0940 M Ag. If solid Na3PO4 is added to this mixture, which of the phosphate species would

Olenka [21]

Answer:

C. $Ca_3(PO_4)_2$ will precipitate out first

the percentage of $Ca^{2+}$ remaining = 12.86%

Explanation:

Given that:

A solution contains:

$[Ca^{2+}] = 0.0440 \ M$

$[Ag^+] = 0.0940 \ M$

From the list of options , Let find the dissociation of $Ag_3PO_4$

$Ag_3PO_4 \to Ag^{3+} + PO_4^{3-}$

where;

Solubility product constant Ksp of $Ag_3PO_4$ is $8.89 \times 10^{-17}$

Thus;

$Ksp = [Ag^+]^3[PO_4^{3-}]$

replacing the known values in order to determine the unknown ; we have :

$8.89 \times 10 ^{-17} = (0.0940)^3[PO_4^{3-}]$

$\dfrac{8.89 \times 10 ^{-17}}{(0.0940)^3} = [PO_4^{3-}]$

$[PO_4^{3-}] =\dfrac{8.89 \times 10 ^{-17}}{(0.0940)^3}$

$[PO_4^{3-}] =1.07 \times 10^{-13}$

The dissociation of $Ca_3(PO_4)_2$

The solubility product constant of $Ca_3(PO_4)_2$ is $2.07 \times 10^{-32}$

The dissociation of $Ca_3(PO_4)_2$ is :

$Ca_3(PO_4)_2 \to 3Ca^{2+} + 2 PO_{4}^{3-}$

Thus;

$Ksp = [Ca^{2+}]^3 [PO_4^{3-}]^2$

$2.07 \times 10^{-33} = (0.0440)^3 [PO_4^{3-}]^2$

$\dfrac{2.07 \times 10^{-33} }{(0.0440)^3}= [PO_4^{3-}]^2$

$[PO_4^{3-}]^2 = \dfrac{2.07 \times 10^{-33} }{(0.0440)^3}$

$[PO_4^{3-}]^2 = 2.43 \times 10^{-29}$

$[PO_4^{3-}] = \sqrt{2.43 \times 10^{-29}$

$[PO_4^{3-}] =4.93 \times 10^{-15}$

Thus; the phosphate anion needed for precipitation is smaller i.e $4.93 \times 10^{-15}$ in $Ca_3(PO_4)_2$ than in $Ag_3PO_4$ $1.07 \times 10^{-13}$

Therefore:

$Ca_3(PO_4)_2$ will precipitate out first

To determine the concentration of $[Ca^+]$ when the second cation starts to precipitate ; we have :

$Ksp = [Ca^{2+}]^3 [PO_4^{3-}]^2$

$2.07 \times 10^{-33} = [Ca^{2+}]^3 (1.07 \times 10^{-13})^2$

$[Ca^{2+}]^3 = \dfrac{2.07 \times 10^{-33} }{(1.07 \times 10^{-13})^2}$

$[Ca^{2+}]^3 =1.808 \times 10^{-7}$

$[Ca^{2+}] =\sqrt[3]{1.808 \times 10^{-7}}$

$[Ca^{2+}] =0.00566$

This implies that when the second cation starts to precipitate ; the concentration of $[Ca^{2+}]$ in the solution is 0.00566

Therefore;

the percentage of $Ca^{2+}$ remaining = concentration remaining/initial concentration × 100%

the percentage of $Ca^{2+}$ remaining = 0.00566/0.0440 × 100%

the percentage of $Ca^{2+}$ remaining = 0.1286 × 100%

the percentage of $Ca^{2+}$ remaining = 12.86%

5 0

3 years ago

Which transformation represents light energy transforming into chemical energy?

ZanzabumX [31]

I think the best answer is C. Since the light energy would be the sun and chemical energy being the glucose that feeds the plant.

4 0

2 years ago

Which human activity would most likely decrease the amount of carbon in the atmosphere?

Allushta [10]

The removal of trees would most likely decrease the amount of carbon in the atmosphere.

Please note that it is useful to add the options provided with the question, in order to get a most accurate answer and have your question answered quicker.

Hope this helps!!

6 0

3 years ago

Read 2 more answers

The charges and sizes of the ions in an ionic compound affect the strength of the electrostatic attraction holding that compound

Nadya [2.5K]

Answer:

order = SrS > SrCl2 > RbCl > CsBr

Explanation:

Comparison of the melting points of compounds is basically dependent on the charge on their cation and anion, the more the charges on the cation and anion, the stronger and greater the force of attraction and as such the melting point will be relatively higher as well.

The ionic radii is also another factor to be considered, the more the distance between ions, the lesser the bond strength and the lesser the melting point.

from the options, in terms of ionic radii SrS > SrCl2 and RbCl > CsBr

also both SrS and SrCl2 have more charges on their ions compared to RbCl and CsBr and as such the arrangement of the highest melting point will be in the order SrS > SrCl2 > RbCl > CsBr.

6 0

2 years ago

The reaction between iron(II) oxide and carbon monoxide produces iron and carbon dioxide. How many moles of iron can be obtained

My name is Ann [436]

Answer:

4.75 moles of Fe

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

FeO + CO —> Fe + CO2

Now, we can determine the number of mole of iron, Fe produced by the reaction of 4.75 mol of FeO with excess CO as follow:

From the balanced equation above,

1 mole of FeO reacted to produce 1 mole of Fe.

Therefore, 4.75 moles of FeO will also react to produce 4.75 moles of Fe.

Therefore, 4.75 moles of Fe is produced.

4 0

2 years ago

The properties of a substance are not affected by chemical reactions. O True O False