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Marizza181 [45]

3 years ago

5

What is the most efficient way to make up a hepes buffer at ph 8.5?

1 answer:

ruslelena [56]3 years ago

4 0

$pka$ value of HEPES is 7.5.

A proper amount of HEPES is mixed with distilled water (sterilized) to avoid any contamination. After that, check the pH with the help of pH scale or pH meter.

First, take the basic form of HEPES and then add hydrochloric acid drop by drop to bring down the pH at 8.5.

When pH reaches 8.5; the buffer solution is filtered and placed in the glass container and then covered by aluminium foil.

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Calculate the molar mass of each of the following:

Allushta [10]

Explanation:

Molar mass

The mass present in one mole of a specific species .

The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .

(a) S₈

Molar mass of of the atoms are -

sulfur, S = 32 g/mol.

Molar mass of S₈ = 8 * 32 g/mol. = 256 g/mol.

(b) C₂H₁₂

Molar mass of of the atoms are -

Hydrogen , H = 1 g/mol

Carbon , C = 12 g/mol

Molar mass of C₂H₁₂ = ( 2 * 12 ) + (12 * 1 ) = 36 g /mol

(c) Sc₂(SO₄)₃

Molar mass of of the atoms are -

sulfur, S = 32 g/mol.

oxygen , O = 16 g/mol.

scandium , Sc = 45 g/mol.

Molar mass of Sc₂(SO₄)₃ = (2 * 45 ) + ( 3 *32 ) + ( 12 * 16 ) = 378 g /mol

(d) CH₃COCH₃ (acetone)

Molar mass of of the atoms are -

Carbon , C = 12 g/mol

oxygen , O = 16 g/mol.

Hydrogen , H = 1 g/mol

Molar mass of CH₃COCH₃ (acetone) = (3 * 12 ) + ( 1 * 16 ) + ( 6 * 1 ) = 58g/mol

(e) C₆H₁₂O₆ (glucose)

Molar mass of of the atoms are -

Carbon , C = 12 g/mol

oxygen , O = 16 g/mol.

Hydrogen , H = 1 g/mol

Molar mass of C₆H₁₂O₆ (glucose) = ( 6 * 12 ) + ( 12 * 1 ) + ( 6 * 16 ) = 108g/mol.

6 0

3 years ago

Identify the major attractive force in HF molecules.A) London Dispersion Forces (LDFs)

Llana [10]

Answer:

C) hydrogen bonding

Explanation:

All atoms and molecules have London Dispersion Forces between them, but they are usually overshadowed but the much stronger forces. In this scenario the major attractive force in HF molecules are hydrogen bonds. Hydrogen bonds are electrostatic forces of attraction found when Hydrogen is bonded to a more electronegative atom such as Oxygen, Chlorine and Fluorine.

6 0

3 years ago

List four examples of diffusion seen in daily life.

babunello [35]

Answer:

Spraying perfume in one corner of the room and the smell travels to the other side of the room

Explanation:

6 0

3 years ago

A neutral atom has the same number of _____ in it’s nucleus as____ in its electron cloud

rusak2 [61]

Answer:

the neutul atom has the same number of protons in its neclues as positive in its electron cloud#

Explanation:

8 0

3 years ago

Please answer asap! worth 35 points!

Gnesinka [82]

Answer:

The enthalpy of the solution is -35.9 kJ/mol

Explanation:

<u>Step 1:</u> Data given

Mass of lithiumchloride = 3.00 grams

Volume of water = 100 mL

Change in temperature = 6.09 °C

<u>Step 2:</u> Calculate mass of water

Mass of water = 1g/mL * 100 mL = 100 grams

<u>Step 3:</u> Calculate heat

q = m*c*ΔT

with m = the mass of water = 100 grams

with c = the heat capacity = 4.184 J/g°C

with ΔT = the chgange in temperature = 6.09 °C

q = 100 grams * 4.184 J/g°C * 6.09 °C

q =2548.1 J

<u>Step 4:</u> Calculate moles lithiumchloride

Moles LiCl = mass LiCl / Molar mass LiCl

Moles LiCl = 3 grams / 42.394 g/mol

Moles LiCl = 0.071 moles

<u>Step 5:</u> Calculate enthalpy of solution

ΔH = 2548.1 J /0.071 moles

ΔH = 35888.7 J/mol = 35.9 kJ/mol (negative because it's exothermic)

The enthalpy of the solution is -35.9 kJ/mol

3 0

3 years ago