Question

How many grams of Na_{2}CO_{3} (FM 105.99)
should be mixed with 6.41 g of NaHCO_{3} (FM 84.01) to
produce a 100 mL of buffer with pH of 10.14? (The
*K*_{a}'s of carbonic acid are
*K*_{a1} = 4.46 ✕ 10^{−7} and
*K*_{a2} = 4.69 ✕ 10^{−11}.)

NOTE: Use three significant figures in answer.

Answer #1

**we know that**

**moles = mass / molar mass**

**so**

**moles of NaHC03 = 6.41 / 84.01**

**moles of NaHC03 = 0.07630044**

**we know that**

**for a buffer solution**

**pH = pKa + log [salt / acid ]**

**in this case**

**pH = pKa2 + log [ Na2C03 / NaHC03]**

**now**

**we know that**

**pKa2 = -log Ka2**

**so**

**pH = -log Ka2 + log [ Na2C03 / NaHC03]**

**10.14 = -log 4.69 x 10-11 + log [ Na2C03 /
NaHC03]**

**[ Na2C03 / NaHC03] = 0.6474**

**now**

**we know that**

**concentration = moles / volume**

**as the final volume is same**

**ratio of concentrations = ratio of moles**

**so**

**moles of Na2C03 / moles of NaHC03 = 0.6474**

**so**

**moles of Na2C03 / 0.07630044 = 0.6474**

**moles of Na2C03 = 0.0494**

**now**

**mass = moles x molar mass**

**so**

**mass of Na2C03 = 0.0494 x 105.99**

**mass of Na2C03 = 5.236**

**so**

**5.24 grams of Na2C03 is required**

How many grams of Na2CO3 (FM 105.99) should be mixed with 3.97 g
of NaHCO3 (FM 84.01) to produce a 100 mL of buffer with pH of
10.03? (The Ka's of carbonic acid are Ka1 = 4.46 ✕ 10−7 and Ka2 =
4.69 ✕ 10−11.)

How many grams of Na2CO3 (FM 105.99) should be mixed with 4.61 g
of NaHCO3 (FM 84.01) to produce a 100 mL of buffer with pH of
10.44? (The Ka's of carbonic acid are Ka1 = 4.46 ✕ 10−7 and Ka2 =
4.69 ✕ 10−11.)

How many grams of solid Na2CO3 and solid NaHCO3 are needed to
prepare 600 mL of 250 mM bicarbonate buffer at pH = 4.5? Carbonic
acid has two pKa values at 3.77 and 10.20

How many grams of Na2CO3 (MW = 105.9885 g/mole) need to be
dissolved in a 0.75 M NaHCO3 solution in order to create a buffer
at a pH 9.75 that has a total volume of 500.0 mL? (The answer is
13g Na2CO3 but show step by step on how to get to the answer)

Carbonic acid (H2CO3) is a weak diprotic acid with
Ka1=4.43�10^-7 and Ka2=4.73�10^-11. When sodium
bicarbonate (NaHCO3) is titrated with hydrochloric acid (HCl), it
acts as a weak base according to the equation
NaHCO3(aq)+HCl(aq)?H2CO3(aq)+NaCl(aq)
1)What volume of 0.180M HCl is required for the
complete neutralization of 1.50g of NaHCO3 (sodium
bicarbonate)?
2)What volume of 0.120M HCl is required for the
complete neutralization of 1.10g of Na2CO3 (sodium carbonate)?
3)A sample of NaOH (sodium hydroxide) contains a small amount of
Na2CO3 (sodium...

How many grams of dipotassium phthalate (242.3 g/mol) must be
added to 200 mL of 0.150 M potassium hydrogen phthalate to give a
buffer of pH 5.40? The Ka's for phthalic acid are 1.12 x 10-3 and
3.90 x 10-6.

a. How many grams of sodium lactate, NaC3H5O3 should be added to
1.00L of 0.150M lactic acid, HC3H5O3 to form a buffer solution with
a pH of 3.90? (Ka= 1.4 x 10^-4 for lactic acid)
b. What is the pH of the buffer solution containing 0.10moles of
acetic acid and 0.13moles of sodium acetate in 1.0L after adding
0.02 moles of KOH?
c. What will the pH be if 0.15mol HA (pKa= 2.00) and 0.27 mole
A- are mixed together...

1) Fill in the blanks with either less or more.
Consider two acids - HF and NH3. Fluorine is________
electronegative than N and therefore HF will be__________ acidic
than NH3.
2) Consider a 1.55 x 10-2M solution of
H2CO3 where Ka1 = 4.5 x
10-7 and Ka2 = 4.7 x 10-11.
The concentration of CO32- is ______ x
10^_________
Note: Is there is not exponent then answer
10^0.
3).Buffer solutions with a pH of 10 can be
prepared using sodium...

How many grams of dipotassium succinate trihydrate
(K2C4H4O4·3H2O, MW = 248.32 g/mol) must be added to 710.0 mL of a
0.0304 M succinic acid solution to produce a pH of 5.989? Succinic
acid has pKa values of 4.207 (pKa1) and 5.636 (pKa2). (Note:
324.45g is not correct)

n this exercise, weighed samples of a solid unknown containing
NaCl and NaHCO3 react with hydrochloric acid. The volume of the CO2
liberated by the reaction in the gas phase is measured with a gas
collection syringe. From the volume we can calculate the number of
moles of CO2 in the gas phase using the ideal gas
approximation.
Since the CO2 is generated in an aqueous environment (aqueous
HCl), some CO2 will dissolve in the liquid phase. The amount of...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 1 minute ago

asked 4 minutes ago

asked 16 minutes ago

asked 18 minutes ago

asked 22 minutes ago

asked 22 minutes ago

asked 38 minutes ago

asked 47 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago