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Tatiana [17]
2 years ago
13

You need to prepare 1 L of the citric acid/citrate buffer. You have chosen to use Method 1 (see lab presentation). Calculate the

pH of a solution prepared by mixing 300 mL of 0.45 M citric acid acid and 100 mL of 0.65 M NaOH plus water to a final volume of one liter. The Ka of citric acid is 7.24 x 10-4.
Chemistry
1 answer:
prisoha [69]2 years ago
8 0

Answer:

3.11 is the pH of the buffer

Explanation:

The pH of a buffer is obtained using H-H equation:

pH = pKa + log [Conjugate base] / [Weak acid]

<em>Where pH is the pH of the buffer, pKa = -log Ka = 3.14 for the citric buffer and [] could be taken as the moles of each species.</em>

The citric acid,HX (Weak acid), reacts with NaOH to produce sodium citrate, NaX (weak base) and water:

HX + NaOH → H2O + NaX

That means the moles of NaOH added = Moles of sodium citrate produced

And the resulitng moles of HX = Initial moles - Moles NaOH added

<em>Moles HX and NaX:</em>

Moles NaOH = 0.100L * (0.65mol / L) = 0.065 moles NaOH = Moles NaX

Moles HX = 0.300L * (0.45mol / L) = 0.135 moles HX - 0.065 moles NaOH = 0.070 moles HX

Replacing in H-H equation:

pH = 3.14 + log [0.065mol] / [0.070mol]

pH = 3.11 is the pH of the buffer

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Finger [1]

Answer:

the Balogna could carry  19 passengers if filled with Hydrogen.

the Balogna could carry  17 passengers if filled with Helium.

Explanation:

Given that:

the radius of the cylinder r = 4.0 cm

the height h = 40 m

the volume of the cylinder will be:

V = \pi r^2 h

V = π (4.0 m)² (40)

V = 2010.62 m³.

where the density of the air = 1.23 kg/m³

the mass of the displaced air = Volume V ×density of the air

= 2010.62 m³ × 1.23 kg/m³

= 2473.0626 kg

To calculate how many passengers the Balogna could carry if it were filled with hydrogen, we have the following:

We are given the density of H₂ to be = 0.090 kg/m³

Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen

= 2010.62 m³ × 0.090 kg/m³

= 180.9558 kg

The total mass of the balloon = mass of H₂ + mass of empty balloon.

The total mass of the balloon = (180.9558+ 750) kg

= 930.9558 kg

Now, the Mass difference = mass of the air displaced -total mass of the balloon.

the Mass difference =  (2473.0626 - 930.9558 ) kg

the Mass difference =  1542.1068 kg

∴

number of persons = mass difference/ mass of passenger

the number of persons = 1542.1068 kg /80 (kg/person)

the number of persons = 19.27 persons

the number of passengers \simeq 19 passengers.

To calculate how many passengers the Balogna could carry if it were filled with helium, we have the following:

We are given the density of Helium to be =  0.18 kg/m³

Therefore, the mass of Helium in the balloon = Volume V × density of the hydrogen

= 2010.62 m³ × 0.18 kg/m³

= 361.9116 kg

The total mass of the balloon = mass of Helium + mass of empty balloon.

The total mass of the balloon = (361.9116 + 750) kg

= 1111.9116 kg

Now, the Mass difference = mass of the air displaced -total mass of the balloon.

the Mass difference =  (2473.0626 - 1111.9116 ) kg

the Mass difference =  1361.151 kg

∴

number of persons = mass difference/ mass of passenger

the number of persons =  1361.151 kg /80 (kg/person)

the number of persons = 17.01 persons

the number of passengers \simeq 17 passengers.

7 0
2 years ago
Identify each charge of the subatomic particles ? <br><br> Help me please ASAP
baherus [9]

Answer:

Particle: Charge:

Proton +1

Neutron 0

Electron -1

6 0
2 years ago
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,n
Liula [17]

Answer:

yes

Explanation:

n,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

4 0
3 years ago
What is the predicted change in the boiling point of water when 1.50 g of
dezoksy [38]

Answer:

0.00735°C

Explanation:

By seeing the question, we can see the elevation in boiling point with addition of BaCl₂ in water

⠀

\textsf {While} \:  \sf  {\Delta T_b}  \: \textsf{expression is used} \\  \textsf {for elevation of boiling point}

⠀

⠀

<u>The</u><u> </u><u>elevation</u><u> </u><u>in</u><u> </u><u>boiling</u><u> </u><u>point</u><u> </u><u>is</u><u> </u><u>a</u><u> </u><u>phenomenon</u><u> </u><u>in</u><u> </u><u>which</u><u> </u><u>there</u><u> </u><u>is</u><u> </u><u>increase</u><u> </u><u>in</u><u> </u><u>boiling</u><u> </u><u>point</u><u> </u><u>in</u><u> </u><u>solution</u><u>,</u><u> </u><u>when</u><u> </u><u>the</u><u> </u><u>particular</u><u> </u><u>type</u><u> </u><u>of</u><u> </u><u>solute</u><u> </u><u>is</u><u> </u><u>added</u><u> </u><u>to</u><u> </u><u>pure</u><u> </u><u>solvent</u><u>.</u>

⠀

⠀

\sf  \large \underline{The \:  formula \: to \:  be  \: used \:  in \:  this \:  question \:  is}  \\   \boxed{T_b = i \times  K_b \times  m}

⠀

⠀

Where 'i' is van't hoff factor which represents the ratio of observed osmotic pressure and the value to be expected.

and 'i' is 3 (as given in the question)

⠀

'Kb' is molal boiling point constant. And it's value is 0.51°C/mol(given in question)

⠀

'm' represent the molality of solution. Molatity is no. of moles of solution present in 1kg of solution.

⠀

⠀

<u>To</u><u> </u><u>find</u><u> </u><u>molality</u><u>,</u><u> </u><u>we</u><u> </u><u>have</u><u> </u><u>to</u><u> </u><u>divide</u><u> </u><u>no</u><u>.</u><u> </u><u>of</u><u> </u><u>moles</u><u> </u><u>of</u><u> </u><u>solute</u><u> </u><u>by</u><u> </u><u>weight</u><u> </u><u>of</u><u> </u><u>solution</u>

⠀

While first we need to no. of moles

\sf \implies no. \: of \: moles =  \frac{weight \: of \: solute}{molar \: mass \: of \: solute}  \\  \\ \implies \sf no. \: of \: moles =  \frac{1.5}{208.23}  \\  \\  \sf \implies  no. \: of \: moles = 0.0072

⠀

⠀

<u>Now</u><u>,</u><u> </u><u>we</u><u> </u><u>will</u><u> </u><u>find</u><u> </u><u>molality</u>

⠀

\sf  \hookrightarrow molality =  \frac{no.\: of \: moles}{weight \: of \: solution}  \\  \\  \sf  \hookrightarrow molality =  \frac{0.072}{1.5}  \\  \\  \sf  \hookrightarrow molality = 0.048 \: mol {kg}^{ - 1}

⠀

⠀

\textsf{ \large{ \underline{Now substituting the required values}}}

⠀

\sf \longmapsto \Delta T_b = 3  \times 0.51  \times 0.0048 \\  \\ \\     \boxed{ \tt{ \longmapsto \Delta T_b =0.00735{ \degree}C}}

⠀

⠀

⠀

<u>Henceforth</u><u>,</u><u> </u><u>the</u><u> </u><u>change</u><u> </u><u>in</u><u> </u><u>boiling</u><u> </u><u>point</u><u> </u><u>is</u><u> </u><u>0</u><u>.</u><u>0</u><u>0</u><u>7</u><u>3</u><u>5</u><u>°</u><u>C</u><u>.</u>

7 0
1 year ago
Salt is an ionic compound that is produced when a cation and an anion from an acid-base reaction combine, and solutions of salts
Andrej [43]

Answer:

a. True

Explanation:

The statement given regarding salt is correct,

Salt is ionic in nature, as it is composed of a positive ion, i.e. , cation and a negative ion, i.e. , anion.

Salt can be made by the combination of respective acid and base.

There are three nature of salt, acid, base and neutral.

Hence, from the given statement of the question,

The correct option is a. True.

3 0
2 years ago
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