I need help with finding molar ratio

[ndgkhang]

I am currently using Ca(NO₃)₂*4H₂O and P₂O₅ and I need to have the molar ratio of Ca/P = 1.5
I wonder how could I do that?

Thank you for your help

[ChenBeier]

You need 1 mol of the Calcium nitrate tetra hydrate and 0.333 mol of the phosphorous Penta oxide.

One 1 mol Ca(NO₃)₂*4H₂O correspond to 1 mol Ca
and 1 mol P₂O₅ correspond to 2 mol P

Ratio Ca/P = 1.5 = 1/0,666 mol = 1 Ca(NO₃)₂*4H₂O /0,333 P₂O₅

With the molar mass of each component you can calculate the mass in g.

[ndgkhang]

You need 1 mol of the Calcium nitrate tetra hydrate and 0.333 mol of the phosphorous Penta oxide.

One 1 mol Ca(NO₃)₂*4H₂O correspond to 1 mol Ca
and 1 mol P₂O₅ correspond to 2 mol P

Ratio Ca/P = 1.5 = 1/0,666 mol = 1 Ca(NO₃)₂*4H₂O /0,333 P₂O₅

With the molar mass of each component you can calculate the mass in g.

Hi there,

Thank you very much for your reply, I found out I need to mix 236.15g of Calcium Nitrate Tera Hydrate with 94.53537g of Phosphorous Penta Oxide ratio in order to produce Ca/P = 1.5

Another quick question, there's this literature I have been reading and it suggested me to dissolve Ca(NO₃)₂*4H₂O and P₂O₅ in absolute ethanol to form 0.01 mol and 0.003 mol solution. I dont understand that sentence, could you help explain what does it mean to dissolve down to 0.01 mol and 0.003 mol, and does that have anything to do with the mass I just found by your help?

Thank you again for your help.

[ChenBeier]

The calculation for P₂O₅ is wrong its only 47,328 g

Molar weight of P₂O₅ is 142 g/ mol. Multiplied with 0.3333 is 47.3286 g

The other answer is

1 mol to 0.333 mol can also diluted down

In this case 0.01 mol to 0.0033 mol

What means in mass 2,36 g Calcium Nitrate tetra hydrate and 0,473 g Phosphorous penta oxide

[ndgkhang]

The calculation for P₂O₅ is wrong its only 47,328 g

Molar weight of P₂O₅ is 142 g/ mol. Multiplied with 0.3333 is 47.3286 g

The other answer is

1 mol to 0.333 mol can also diluted down

In this case 0.01 mol to 0.0033 mol

What means in mass 2,36 g Calcium Nitrate tetra hydrate and 0,473 g Phosphorous penta oxide

Thank you for the correction, I was looking at the P₄O₁₀ Molar mass.
For the dissolve in absolute ethanol to form 0.01 mol (Calcium Nitrate Tetrahydrate) and 0.003 mol (phosphorous pentoxide), which equation I can use to find how much mass in how much volume of ethanol to dissolve to desire mol?

[ChenBeier]

It is the same equation like above. I wrote the result already. It is only 1/100 of the calculated value.

Moles = mass/ Molar mass, n = m/M

In case of P₄O₁₀ is the result more worse, because 1 mol P₄O₁₀ = 4 mol P

It is more worse then 1/0.166666 Ca/P₄O₁₀ = 1/4*0,16666 Ca/P = 1/0,66666 = 1.5

The mass will be still the same either calculated as P₂O₅ or P₄O₁₀ 47,3 g.

The volume is calculated to 1 Liter. Concentration normaly given as mol/l.

[ndgkhang]

It is the same equation like above. I wrote the result already. It is only 1/100 of the calculated value.

Moles = mass/ Molar mass, n = m/M

In case of P₄O₁₀ is the result more worse, because 1 mol P₄O₁₀ = 4 mol P

It is more worse then 1/0.166666 Ca/P₄O₁₀ = 1/4*0,16666 Ca/P = 1/0,66666 = 1.5

The mass will be still the same either calculated as P₂O₅ or P₄O₁₀ 47,3 g.

The volume is calculated to 1 Liter. Concentration normaly given as mol/l.

Hi there,

As long as I use Ca/P = 1.5 it would work out well, right? either: 1/0.333 or, 0.01/0.0033, etc... But since the literature suggested to dissolved down to 0.01 and 0.0033 in absolute ethanol, Ca and P respectively. It means that I would need to dissolve 2.36g Ca(NO₃)₂*4H₂O in 1L of absolute ethanol and 0.473g of P₂O₅ in 1L of absolute ethanol. Do you have any idea why the literature suggested me to dissolve down to 0.01 and 0.0033 mol instead of 1 and 0.33 mol in ethanol? Would it be more concentrated but since the Ca/P is the same ratio, it would work out as well?

Quoted Synthesis of B-tricalcium phosphate by H. Chaair, H. Labjar , O. Britel
"Calcium nitrate tetrahydrate (Ca(NO)₂ 4H₂O, Merck) and phosphorus pentoxide (P, Merck) were selected as Ca and P precursors, respectively. A design amount of Ca(NO₃), 4 H₂O and P₂O₅ was dissolved in absolute ethanol to form 0.01 mol and 0.003 mol solution, respectively. The solutions were mixed as initial mixed precursor solution and were continuously stirred for 30 minutes at ambient temperature until a white transparent gel was obtained."

[ChenBeier]

Its only a diluted solution nothing else. You can choose any amount only to achieve Ca/P = 1.5. Maybe its also a matter of soloubility. I would go according the receipe.

[ndgkhang]

Its only a diluted solution nothing else. You can choose any amount only to achieve Ca/P = 1.5. Maybe its also a matter of soloubility. I would go according the receipe.

Thank you for your help. I will try it out according to the recipe

[emmausa]

To achieve a molar ratio of Ca/P = 1.5, you would need to use approximately 0.9 grams of Ca(NO₃)₂·4H₂O for every 1 gram of P₂O₅. This ratio would give slither io you the desired molar ratio of 1.5.