# How many grams of Na2HPO4 and NaH2PO4 to prepare 200 mL with pH 8.25 and sum of ions is 0.5M

28,457 results

### Chemistry

How do I calculate the amount of grams of Na2HPO4 and NaH2PO4 to prepare 200 mL of a buffer with an 8.25 pH so the sum of the concentrations of HPO4 and H2PO4 ions is 0.5 M? Does this involve writing a Ka expression and equilibrium? I am confused and Thanks for your help!

### Chemistry

How do I calculate the amount of grams of Na2HPO4 and NaH2PO4 to prepare 200 mL of a buffer with an 8.25 pH so the sum of the concentrations of HPO4 and H2PO4 ions is 0.5 M? Does this involve writing a Ka expression and equilibrium? I am confused and Thanks for your help!

### Chemistry

Calculate the amount of NaH2PO4 and Na2HPO4 needed to prepare 100 mL of a buffer with a pH = 8.25 so that the sum of concentrations of HPO4 and H2PO4 ions is 0.5 M. Where do I start? :/

### Chemistry

pKa1 = 2.148, pKa2 = 7.198, pKa3 = 12.375 You wish to prepare 1.000L of a 0.0100M Phosphate buffer at pH7.55. To do this, you choose to use mix the two salt fomrs involved in the second ionization, NaH2PO4 and Na2HPO4, in a 1.000L volumetric flask and add water to the mark. ...

### Analytical Chemistry

Phosphoric acid is a triprotic acid with the following pKa values: pka1: 2.148 pka2: 7.198 pka3: 12.375 You wish to prepare 1.000 L of a 0.0100 M phosphate buffer at pH 7.45. To do this, you choose to use mix the two salt forms involved in the second ionization, NaH2PO4 and ...

### Chemistry

A buffer prepared by mixing equal amounts of the salts Na2HPo4 and NaH2PO4 to give a total phosphate concentration of 0.1M. What is the concentration of Na ions? I believe it is 0.3M but am having trouble understanding why when I write out the dissociation of the Na2HPo4 and ...

### Chemistry

A buffer prepared by mixing equal amounts of the salts Na2HPo4 and NaH2PO4 to give a total phosphate concentration of 0.1M. What is the concentration of Na ions? I believe it is 0.3M but am having trouble understanding why when I write out the dissociation of the Na2HPo4 and ...

### Chemistry

To prepare 500.00 mL of 0.300 M buffer with a pH of 7.4. NaH2PO4/Na2HPO4 How many grams of each should be added to the 500.00mL flask to create this buffer?

### chemistry

how to prepare 1M,50ml buffer solution by taking Na2HPO4 and NaH2PO4.

### science

How can i prepare a 100ml, 0.1M phosphate buffer solution (pH = 7) out of Na2HPO4 and NaH2PO4

### pharmachemistry

How can i prepare a 100ml, 0.1M phosphate buffer solution (pH = 5) out of Na2HPO4 and NaH2PO4

### Chemistry

How would you calculate the pH of the buffer if 1.0mL of 5.0M NaOH is added to 20.0mL of this buffer? Can someone please explain to me how to do B and C step by step so I could understand it clearly? :) Say, for example, that you had prepared a buffer in which you mixed 10.30 ...

### Chemistry

How would you calculate the pH of the buffer if 1.0mL of 5.0M NaOH is added to 20.0mL of this buffer? Can someone please explain to me how to do B and C step by step so I could understand it clearly? :) Say, for example, that you had prepared a buffer in which you mixed 10.30 ...

### Chemistry

Prepare 250ml of 0.2M phosphate buffer of pH 6.4.starting from Na2HPO4,NaH2PO4,0.129N NaOH solution.

### Biochemistry

Write up the recipe to make 100mL of a 200mM phosphate buffer, pH 7.0 by using: (a) only NaH2PO4 (MW 120g/mol) and NaOH (1.00M) (b) only Na2HPO4 (MW 142g/mol) and HCl (1.00M) (c) only Na2HPO4 and NaH2PO4 Please help me. I don't seem to understand how to even start...... Thanks

### college chemistry

which of the following combinations is not suitable for making a buffer? h3po4 and nah2po4 na2co3 and nahco3 nh4cl and nh3 nah2po4 and na2hpo4 hclo4 and naclo4

### chemistry

A buffer is prepared consisting of 0.75 mol of sodium dihydrogenphosphate, NaH2PO4, and 0.60 mol of sodium hydrogenphosphate, Na2HPO4, dissolved in 600.0 mL of water. The Ka for the dihydrogenphosphate ion is 6.2 x 10–8 at 25°C. Which of the following is another possible ...

### Chemistry

You are instructed to create 200. mL of a 0.27 M phosphate buffer with a pH of 7.8. You have phosphoric acid and the sodium salts NaH2PO4, Na2HPO4, and Na3PO4 available. (Enter all numerical answers to three significant figures.) H3PO4(s) + H2O(l) equilibrium reaction arrow ...

### ap chem

you have 1.00 liter each of 0.10 M Na3PO4, Na2HPO4, NaH2po4 ka 1= 7.5*10^-3 ka2=6.2*10^-8 ka3=4.8*10^-13 a) prepare 500 ml of a buffer with PH= 7.6 b) how much 0.10 M HCL must be added to the 500ml of buffer to result in a PH=7.2 after the addition?

### chemistry

prepare a phosphate buffer with pH= 7 from solid NaH2PO4 (pKa =7.21) and Na2HPO4. 1) calculate the ratio of [CB]/[acid] I got the ratio as 0.62 2) calculate the mass of each component required to make 1L of a .1 M buffer solution 3) if the pH is 7.10, how would you adjust it ...

### Chemistry

How many moles of conjugate base (Na2HPO4) are present in 40mL of .010M buffer at pH 7.5 vs at pH 6? Buffer was made up of Na2HPO4 and NaH2PO4. pH=pKa +log[A/HA]; pKa=7.2.... When I did the calculations I got the same amount as if it were in a 0.1M buffer at the same pH's so I...

### medicine

3.6gm na2hpo4 + 1gm nah2po4

### Chem

What is the pH of .1M: FeSO4 Na2HPO4 NaH2PO4 NaF

### Biochemistry

You are asked to prepare 2 L of 50 mM sodium phosphate pH 7.0. The pK2 of phosphate is 6.8. What are the amounts of sodium phosphate mono basic monohydrate (NaH2PO4 • 1H2O, MW=137.99 Da) and anhydrous sodium phosphate dibasic (Na2HPO4, MW=141.96 Da) that must be weighed out?

### Chemistry

What weights of NaH2PO4 and NaHPO4 would be required to prepare a buffer solution of pH 7.45 that has an ionic strength of 0.1? pKa2=7.12 , mwt NaH2Po4=120g/mol NaHPO4=142 g/mol using the henderson-hasselbalch equation i got that the ratio of the concentration of NaH2PO4 to ...

### Chemistry

Calculate the pH of a buffer solution that contains 0.60 M NaH2PO4, and 0.26 M Na2HPO4.

### BIO chemistry

What is the pH of a mixture of 0.042M NaH2PO4 and 0.054M Na2HPO4

### chemistry

How many grams of sodium chloride, NaCl (fw 58.44), are required to prepare exactly 200 mL of a solution that is 600 ppm in sodium ions?

### AP CHEMISTRY

What would be the pH of a solution prepared by combining equal quantities of NaH2PO4 and Na2HPO4? Explain with an equation.

### chemistry

How would you prepare 1.000 L of a 0.200 M phosphate buffer at pH 6.90 using crystalline Na2HPO4 and a solution of 1.000 M HCl?

### chemistry

How would you prepare 1.000 L of a 0.200 M phosphate buffer at pH 7.02 using crystalline Na2HPO4 and a solution of 1.000 M HCl?

### Chemistry

How would I make 100mL of a .100 M phosphate buffer with a pH of 7.2 using 1 M NaH2PO4 and Na2HPO4 solid (MW= 142 g/mol)?

### science

If 1,2,3,4 moles of H3po4, nah2po4, na2hpo4, and na3po4 are mixed in an aqueous solution.find the pH. Ka1=10^-3, Ka2=10^-7, ka3= 10^-13

### chemistry

Phosphoric acid is a triprotic acid with the following pKa values: pKa1=2.148 pKa2=7.198 pKa3=12.375 You wish to prepare 1.000 L of a 0.0200 M phosphate buffer at pH 7.11. To do this, you choose to use mix the two salt forms involved in the second ionization, NaH2PO4 and ...

### chemistry

Phosphoric acid is a triprotic acid with the following pKa values: pKa1=2.148 pKa2=7.198 pKa3=12.375 You wish to prepare 1.000 L of a 0.0200 M phosphate buffer at pH 7.11. To do this, you choose to use mix the two salt forms involved in the second ionization, NaH2PO4 and ...

### Chem wondering how to set it up

1.) A biochemistry student wants to make 4 liters of a phosphate solution using 48.6 g Na2HPO4 (FW=141.96) What is the concentration of this solution? 2. When she reaches the storeroom she finds that there is no Na2HPO4, however there is a bottle of hydrate Na2HPO4 * 7H20. (FW...

### Chem still confused

1.) A biochemistry student wants to make 4 liters of a phosphate solution using 48.6 g Na2HPO4 (FW=141.96) What is the concentration of this solution? 2. When she reaches the storeroom she finds that there is no Na2HPO4, however there is a bottle of hydrate Na2HPO4 * 7H20. (FW...

### Chemistry

mixing 100ml of 0.015M Nah2PO4 and 100ml of NA2HPO4. What is the pH? This has got to be simple but why am I having trouble with it?

### BioChem

Write the chemical equation for the reaction that occurs when you add NaOH solution to NaH2PO4/Na2HPO4 buffer solution

### chemistry

What happens when 4ml of 1M HCL is added to 100ml buffer made using 5ml 1M Na2HPO4 and 5ml 1M NaH2PO4? The pKa for H+ + HPO4- = H2PO4 is 6.82.

### chemistry

Phosphoric acid is a triprotic acid, so H3PO4, H2PO4 -, and HPO4 2- are all acids. Which of the solutions below would have the lowest pH? 0.1 M NaH2PO4 0.1 M Na2HPO4 0.1 M Na3PO4

### Ap chem

If 200 ml of .300 molarity of silver nitrate are mixed with 350 ml of .500 molarity calcium chloride ions how many grams of percipitate are formed? How many moles of each ions are present?

### chemistry 2

You are instructed to create 800. mL of a 0.69 M phosphate buffer with a pH of 7.6. You have phosphoric acid and the sodium salts NaH2PO4, Na2HPO4, and Na3PO4 available. what is the molarity needed for the acid component of the buffer?What is the molarity needed for the base ...

### Chemistry

I have the answer to this question but the book does not explain WHY this is a good buffer solution? It uses pH=pKa - log(base/acid) and shows 7.2=7.2 - log(1). I don't understand why they can only use pKa7.2 and ignore the pKa 12.7. You are instructed to prepare 100ml of a 0....

### Chemistry

I need to calculate the amount of NaH2PO4 (in grams) and 1.00M NaOH solution (in ml) needed to make 250 ml of 0.20M H2PO4- at pH 8.00. My work is lengthy and involved but the answer I got was 7.00 ml of the NaOH and 0.0070 moles of the NaH2PO4 needed. Can you tell me if I am ...

### Chemistry

I need to calculate the amount of NaH2PO4 (in grams) and 1.00M NaOH solution (in ml) needed to make 250 ml of 0.20M H2PO4- at pH 8.00. My work is lengthy and involved but the answer I got was 7.00 ml of the NaOH and 0.0070 moles of the NaH2PO4 needed. Can you tell me if I am ...

### Chemistry

Calculate the change in pH if 0.050 g of solid NaOH is added to 250 mL of a buffer solution that contains 0.80 M NaH2PO4 and 0.17M Na2HPO4. I found the pH of the buffer solution to be 6.54.

### Science

How to prepare 10mM NaH2PO4?

### chemistry

What is the theoretical yield in grams of the precipitate starting with 1.250 moles of iron ions (charge is +3) and 60.00 grams of hydroxide ions?

### Chemistry

Take into account correction factors for phosphate buffers, predict the pH when 0.50ml of 1M HCl is added to 40mL of .10M buffer at expected pH 6 and pH 6.5. The buffer was made with Na2HPO4 and NaH2PO4. pKa is 7.2. When I did this before, I got a lower pH for 6.5 than I did ...

### Chemistry

Use the henderson-hasselbalch equation to predict the change in pH when 0.50ml of 1M HCl is added to 40mL of .10M buffer at pH 6 and pH 7.5. My two solutions are Na2HPO4 and NaH2PO4.pKa=7.2 Now I don't even know where to begin and how to use the equation.

### AP Chemistry

Consider the following reaction: PbCl2 + 2 NaOH → Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions, Cl− ...

### Chemistry

Consider the following reaction: PbCl2 + 2 NaOH -> Pb(OH)2 + 2 NaCl What would be the major species observed floating in solution after one mole of PbCl2 and 2 moles of NaOH are mixed in aqueous solution? 1. Na+ ions, Cl− ions and H+ ions 2. Pb2+ ions, Cl− ions ...

### CHEMISTRY

how many grams of sodium carbonate are needed to prepare 0.250 L of an 0.100 M aqueous solution of sodium ions? well normally you go moles=grams/molar mass than M= moles/L but when looking for grams? what do you do........multiple .250 by .100 than divide by the molar mass of ...

### 9th grade chemistry

if you have 55.6 grams of nitrate ions in a compound that consists of nitrate ions and plumbous ions, how many grams of the compound do you have? how do i do this problem im completely stuck!?

### Chemistry

You are to prepare a KH2PO4 and Na2HPO4 solution with pH=7.31. What should the concentration of [2(HPO4) 2-] / [H2PO4-]

### chemistry

how many grams of solid NaOH are required to prepare 200 ml of a .05 M solution?

### Chemistry

My chemistry is bad. I know these are very easy but I cannot solve them . 1. a) Prepare 200 ml of 2 M HCl solution from stock bottle containing 37% w/w HCl and d = 1.2 (g/ml). MWHCl = 36.5 g b) Calculate M of 37% w/w HCl solution? d= 1.2, then solve the above problem 2. a) ...

### chemistry

using the following salts listed below, calculate the moles of acid and conjugate base needed to make 100 ml of 0.50 M, ph 6.5,6.7, and 6.8 phosphate buffer solution. (For H2PO4-, pka=6.64) Salt Molar mass, g/mol KH2PO4 136.09 NaH2PO4*H2O 137.99 Na2HPO4*7H2O 268.09 K2HPO4 174.2

### Chemistry

how would you prepare 500 ml of .2M solution starting with solid NaH2PO4*H20?

### chemistry

how many grams of solid NaOH are required to prepare 200.0 mL of a .050 M solution?

### CHEMISTRY HELP

if you have 55.6 grams of nitrate ions in a compound that consists of nitrate ions and plumbous ions, how many grams of the compound do you have? how do i do this problem im completely stuck!?

### chemistry

What is the chemical equation that describes the complete neutralization of H3PO4 by NaOH? A. H3PO4 + 2NaOH Na2HPO4 + 2H2O B. H3PO4 + H2O H2PO4- + H3O+ C. H3PO4 + NaOH NaH2PO4 + H2O D. H3PO4 + 3NaOH Na3PO4 + 3H2O

### AP CHEMISTRY

A buffer, consisting of H2PO4− and HPO42−, helps control the pH of physiological fluids. Many carbonated soft drinks also use this buffer system. What is the pH of a soft drink in which the major buffer ingredients are 7.20 g of NaH2PO4 and 4.90 g of Na2HPO4 per ...

### AP Chemistry

A buffer, consisting of H2PO4− and HPO42−, helps control the pH of physiological fluids. Many carbonated soft drinks also use this buffer system. What is the pH of a soft drink in which the major buffer ingredients are 7.20 g of NaH2PO4 and 4.90 g of Na2HPO4 per ...

### chemistry

How do I solve this? How many grams of solid NaOH are required to prepare 200 mL of a 0.05 M solution? What will be the concentration expressed in % W/V?

### chemistry

Write the formula of the ionic compound that forms between a. copper(I) ions and chloride ions---CuCl b. copper(II) ions and hydrogen sulfate ions--Cu(HSO4)2 c. lithium ions and iodide ions--LiI d. cobalt(III) ions and phosphate ions---CoPO4

### general chemistry 2

How many grams of urea [CO(NH2)2] would be required to prepare 200 mL of a 5.0 x 10-3 molar solution? Answer

### chemistry

Calculate the number of grams of h2c2o4.2h2o needed to prepare exactly 250mL of a 0.200 N solution of the acid?

### Chemistry Electrolytes

What is the total number of ions formed when 2.00 grams of calcium chloride are dissolved in 100 grams of water. (Ignore any ions formed by the water). Note, this is a bit of a trick question. Read the problem carefully.

### Chemistry 101 Electrolytes

What is the total number of ions formed when 2.00 grams of calcium chloride are dissolved in 100 grams of water. (Ignore any ions formed by the water). Note, this is a bit of a trick question. Read the problem carefully.

### chemestry

H3PO4 is a tribasic acid and one of its salt is NaH2PO4.what volume of 1M NaOH solution should be added to 12g of NaH2PO4 to convert it into Na3PO4?

### chemistry

In an experiment designed to determine the concentration of Cu+2 ions in an unknown solution, you need to prepare 100 mL of 0.10 M CuSO4 as your stock solution. How many grams of CuSO4(s) should you use?

### Chemistry

Can someone help me with these two questions? Thank you! a.) Describe (give instructions) how you would prepare 7.00 L of 0.750 M K2CrO4 from a 2.25 M K2Cro4 stock solution b.) A stock solution containing Ba2+ ions was prepared by dissolving 23.0 grams of pure barium metal in ...

### Chemistry

How many grams of NiSO4*6H2O are needed to prepare 200*10^2 mL of a 3.5*10^-2 M NiSO4 solution?

### Chemistry

If a sample of K3PO4 is found to contain 1.81 grams of K+ ions, how many PO3- 4 ions are present?

### Chemistry

How many grams ammonium chloride and how many milliliters 3.0 M sodium hydroxide should be added to 200 ml of water and diluted to 500 ml to prepare a buffer of 9.50 with a salt concentration of 0.1 M? Ka=9.24

### Chemistry

How man moles of sodium phosphate are there in 0.4 liters of 0.1M Na2HPO4 (MW=141.96 g/mol)? 2.) How many millimoles in 200 ml?

### Chemistry

Calculate the concentration of potassium ions in grams per liter after mixing 100 ml of 0.250 M KCl and 200 ml of 0.100 M K2SO4

### General Chemistry

How many milliliters of 0.5M NaOH must be added to 200 mL of 0.1M NaH2PO4 to make a buffer solution with a pH of 6.9?

### Chemistry

How many milliliters of 1.0 M NaOH must be added to 200. mL of 0.10 M NaH2PO4 to make a buffer solution with a pH of 7.50? (5 points)

### Science

For a cell of the CsCl type (figure 9.18), how is the length of one side of the cell,s, related to the sum of the radii of the ions, r subscript cation + r subscript anion? Figure 9.18 : i . imgur . com / zHj2SGW.png Another question : Consider the NaCl unit shell in figure 9....

### AP Chem - Science

For a cell of the CsCl type (figure 9.18), how is the length of one side of the cell,s, related to the sum of the radii of the ions, r subscript cation + r subscript anion? Figure 9.18 : i . imgur . com / zHj2SGW.png Another question : Consider the NaCl unit shell in figure 9....

### Chemistry

1.What is the pH of a solution containing 0.042 M NaH2PO4 and 0.058 M Na2HPO4 ? The pKa of sodium phosphate is 6.86. pH = 6.86 + log [0.058] / [0.042]; pH = 6.86 + 0.14; pH = 7.00 That is my answer to the above question. The following question is what I am having trouble with...

### CHem

How many oxygen atoms do you have in 2.00 grams of calcium phosphate? My answer is 3.9*10^22 by multiplying avogadros number by (2/31) Am I close? How many Ca^2+ ions do you have in 2.00 grams of calcium phosphate? I am getting 39, am i close? since there are 3 Ca2+ ions per ...

### CALCULUS

The masses of 10 books are found to be in an arithmetic sequence. If their total mass is 13 kg and the lightest book has a mass of 400 grams, what is the mass of the heaviest book? 2,000 grams 2,100 grams 2,200 grams 2,300 grams 2,700 grams

### chemistry

How many grams of NAC2H3O2 must be dissolve in enough water to prepare 250.0 mL of a solution with a pH= 9.200? Molar mass of NaC2H3O2 ia 82.03 g/mol. Ka for C2H3O2H is 1.8x10^-5

### chem

Which shows the greatest metallic character? -Na -K -Rb -Cs Also, What ions are very important for the proper functioning of biologic systems such as nerves and muscles? --oxygen ions --nitride ions --alkali metal ions --alkaline earth metal ions --hydrogen ions

### Chem 2

You are instructed to create 600. mL of a 0.56 M phosphate buffer with a pH of 7.6. You have phosphoric acid and the sodium salts NaH2PO4, Na2HPO4, and Na3PO4 available. (Enter all numerical answers to three significant figures.) H3PO4(s) + H2O(l) equilibrium reaction arrow ...

### chem

im studying for a test and i have no idea where to even start for this practice problem..?? a 0.15M(molarity im assuming)solution of BrCl2 contains.. a).15MBr2+ ions and .30M Cl- ions b).30MBr2+ ions and .15M Cl- ions c).15MBr2+ ions and .15M Cl- ions d).30MBr2+ ions and .30M ...

### Chem

Potassium permanganate (KMnO4) solutions are used for the determination of iron in samples of unknown concentration. As a laboratory assistant, you are supposed to prepare 200. mL of a 0.300 M KMnO4 solution. What mass of KMnO4, in grams, do you need? I got 60, but that's ...

### Chemistry

Activity Coefficient for Phosphate Buffers: How would I calculate the predicted pH for Na2HPO4 and NaH2PO4? For hypothetical pH 6- we added 94mL of H2PO4 and 6mL of HPO4 (for a total of 100mL). But how would I calculate "actual pH"? We measured at two different strengths, 0.1M...

### chemistry calculation

I need to know what volume of liquid phosphoric acid at 85%, H3PO4 with density of 1.685 will replace 5 grams of powdered NaH2PO4. H2O. thanks

### chemistry

what is the pH of the buffer when 4ml of 1M HCl is added to a 100ml buffer solution made using 5ml 1M Na2HPO4 and 5ml 1M NaH2PO4? The pKa for H+ + HPO4- ==> H2PO4 is 6.82. What would happen to the pH if the 100ml buffer had been made up at the starting pH (6.82) using Tris...

### Chemistry

How many moles of potassium sulfate would you need to prepare 1200 grams of 5.0% sulfate (m/m) solution? Calculate the volume of solution of 3.6 NH4CI needed to prepare 350.0ml of 1.24 M NH4CI. How many grams of ammonium chloride are in the solution you created in the above ...

### Analytical chemistry

0.6140 grams of sodium phosphate (Na3PO4) was dissolved in 2 L of water to make a stock solution. 34 mL of this solution is then diluted to 100mL volumetrically to prepare the final solution. Calculate the molarity of phosphate ions in this solution. Answer to 5 decimal places.

### Great Valley

How many moles of potassium sulfate would you need to prepare 1200 grams of 5.0% sulfate (m/m) solution? Calculate the volume of solution of 3.6 NH4CI needed to prepare 350.0ml of 1.24 M NH4CI. How many grams of ammonium chloride are in the solution you created in the above ...

### Math

British sterling silver is a copper-silver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 200 grams of a copper-silver alloy that is 10% copper by weight? (round to the nearest tenth)

### chemistry 185

how are you going to prepare the follwoing phosphate solution which is used in many cell culture medium? 12 liters ;PH 7.4; 0.9%WT (total salts weight is 9.00 grams in one liter) How many grams of what acid? how many grams of the conjugate base?

### Chemistry

Calculate the pH of the buffer formed by mixing 50.0mL of 0.200 F NaH2PO4 with 50.0mL of 0.120 F HCl