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3 years ago

Can you draw the peptide structure at pH 7.0 (including peptide bonds)

Chemistry

1 answer:

ELEN [110]3 years ago

7 0

Answer:

See image below

Explanation:

The image is labeled according to the sequence N'-Trp-Ser-Asg-Gly-Cys-His-COOH' which means that in the main chain of the peptide, the amino group of the Tryptophan and the carboxylic group of the Histidine are free and thus its charge depends on the pH; other groups that rely on the pH are the side groups of the Cysteine and the Histidine.

Overall, ionizable groups in this peptide are:

Amino Group of the Tryptophan (pKa = 9.39)

SH group of the Cysteine (pKa = 8.18)

Secondary amine of the Histidine (pKa = 6.00)

Carboxylic Group of the Histidine (pKa = 1.82)

Then, the amino group of Trp and SH group of Cys are protonated since the peptide is at a pH below the pKa. The secondary amine of the Histidine is deprotonated because the pH is greater than the pKa, as well with its carboxylic acid group.

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Which of the following represents the least number of molecules?

lozanna [386]

Answer:

A ; 20g of water has the least number of molecules

Explanation:

Here, we want to know which of the options represent the least number of molecules;

To calculate this, we are going to first calculate the number of moles using the formula below;

Number of moles = mass/molar mass

Then from the number of moles, we can calculate the number of molecules by multiplying the number of moles by 6.02 * 10^23 molecules

Let’s proceed;

a. That will be 20/18.02 = 1.1099 moles

1.1099 * 6.02 * 10^23 = 6.68 * 10^23 molecules

b. That will be 77/16.06 = 4.8 moles

4.8 * 6.02 * 10^23 = 2.89 * 10*24 molecules

c. That will be 68/42.09 = 1.62 moles

1.62 * 6.02 * 10^23 = 9.73 * 10^23 molecules

d. That will be 100/44.02 = 2.27 moles

2.27 * 6.02 * 10^23 = 1.37 * 10^24 molecules

e. That will be = 84/20.01 = 4.2 moles

4.2 * 6.02 * 10^23 = 2.53 * 10^24 molecules

From all the values obtained, the lowest is 20g of water

6 0

4 years ago

What is the true ratio of atoms in a molecule or formula unit called?

Colt1911 [192]

Answer:

O the molecular formula

Explanation:

The true ratio of atoms in a molecule or formula unit is called the molecular formula.

The molecular formula of a compound shows the true number of atoms that are combining to form a compound.

For example, the molecular formula of water is H₂O.

Empirical formula of a compound is its simplest ratio.
When the number of atoms are divided by the smallest possible factor, it yields the empirical formula.

3 0

3 years ago

A 2-kg box is pushed from rest to a speed of 29.7 m/s in 21 seconds. What is the power require to accelerate the box.

Alona [7]

Answer:

P = 83.16 Watt

Explanation:

Given data:

Mass of box = 2 Kg

velocity of box = 29.7 m/s

Time = 21 sec

Power = ?

Solution:

Formula:

Power = work done/time

Now we will calculate the work done.

W = force × distance ...... (1)

d = speed /time

d = 29.7 m/s× 21 s

d = 623.7 m

Force:

acceleration = 29.7 m/s / 21 s

a = 1.4 m/s²

Force = m×a

Force = 2 kg×1.4 m/s²

Force = 2.8 N

Now we will put the values in equation 1.

W = F × d

W = 2.8 N ×623.7 m

W = 1746.36 Nm

Now for power:

P = W / time

P = 1746 Nm / 21 s

P = 83.16 Watt

5 0

3 years ago

Read 2 more answers

Someone help with this question

Tasya [4]

Answer:

the answer is D the dominant over powers the resecive traits

6 0

3 years ago

b) If 1.5 mole of oxygen reacted, how many mole of iron (III) oxide would be formed from the reaction?

lyudmila [28]

Answer:

If there reacted 1.5 moles of O2, there will be produced 1.0 mol of Fe2O3

Explanation:

Step 1: Data given

Number of moles oxygen reacted = 1.5 moles

Step 2: The balanced equation

4Fe + 3O2 → 2Fe2O3

Step 3: Calculate moles of Fe2O3

For 4 moles Fe consumed, we need 3 moles of O2 to produce 2 moles of Fe2O3

For 1.5 moles O2 consumed, we'll have 2/3 * 1.5 = 1.0 mol of Fe2O3

If there reacted 1.5 moles of O2, there will be produced 1.0 mol of Fe2O3

7 0

4 years ago