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3 years ago

Which pair of symbols represents a metalloid and a noble gas?

1 answer:

5 0

I didn't understand your question at first, I believe an acceptable answer would be As and Ar.

As (arsenic) is a metalloid and Ar (argon) is a noble gas.

Hopefully I was able to help you! :)

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How many hydrogen bonds will be found within an alpha helix that is 18 amino acids long?.

LekaFEV [45]

An alpha helix which is 18 amino acids long will have 12 hydrogen bonds.

<h3>What is alpha helix (α-helix) ?</h3>

The alpha helix (α-helix) is a common in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O. group of the amino acid located four residues earlier along the protein sequence.

The alpha helix is stabilized by hydrogen bonds (shown as dashed lines) from the carbonyl oxygen of one amino acid to the amino group of a second amino acid.

Because the amino acids connected by each hydrogen bond are four apart in the primary sequence, these main chain hydrogen bonds are called "n to n+4.

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5 0

2 years ago

a 1.513 g sample of khp (c8h5o4k) is dissolved in 50.0 ml of di water. when the khp solution was titrated with naoh, 14.8 ml was

JulijaS [17]

molar mass of KHP ( C8H5O4K)= 8*12+5+4*16+39=204

( atomic weights : C=12, H=1, K=39 and O= 16)

moles of KHP= mass/molar mass = 1.513/204 =0.0074

The reaction between KHP and NaOH is

KHC8H4O4(aq) + NaOH(aq) => KNaC8H4O4(aq) + H2O(l)

1 mole of KHP requires 1 mole of NaOH;

moles of KHP=0.0074

moles of NaOH= 0.0074

concentration of NaOH= moles/ Volume in L, 1000ml= 1L, 14.8ml= 14.8/1000L=0.0148L

concentration of NaOH=0.0074/0.0148=0.5M

The molarity of NaOH is 0.5M

Molar Mass:

In chemistry, the molar mass of a compound is defined as the mass of a sample of that compound divided by the amount of substance. This is the number of moles of that sample measured in moles.

Molarity:

Molarity is used to describe the concentration of a solution. Molarity, also called molarity, is the number of moles of solute (dissolved substance) per liter of solution.

Learn more about molarity:

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4 0

1 year ago

the solubility of nitrogen gas is 1.90 mL/dL of blood at 1.00 atm. what is the solubility of nitrogen gas in a deepsea divers bl

leonid [27]

The solubility of nitrogen gas in water is 1.90 mL/dL at 1.00 atm and 13.3 mL/dL at 7.00 atm.

We want to relate the solubility of a gas with its partial pressure.

We can do so using Henry's law.

<h3>What does Henry's law state?</h3>

Henry's law states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid.

C = k × P

where,

C is the concentration of a dissolved gas.

k is the Henry's Law constant.

P partial pressure of the gas.

The solubility of nitrogen gas is 1.90 mL/dL of blood at 1.00 atm.

Since the solvent is basically water, we can understand that the concentration of nitrogen gas is 1.90 mL/dL at 1.00 atm.

We can use this information to calculate Henry's Law constant.

k = C/P = (1.90 mL/dL)/1.00 atm = 1.90 mL/dL.atm

We want to calculate the solubility of nitrogen gas at a pressure of 7.00 atm.

We will use Henry's law.

C = k × P = (1.90 mL/dL.atm) × 7.00 atm = 13.3 mL/dL

The solubility of nitrogen gas in water is 1.90 mL/dL at 1.00 atm and 13.3 mL/dL at 7.00 atm.

Learn more about solubility here: brainly.com/question/11963573

6 0

2 years ago

Which two compounds have the same molecular formula but different chemical and physical properties?

Artist 52 [7]

The answer is (4) CH3CH2OH and CH3OCH3. You need to figure out which pair has the same molecular formula which means that they have the same number of same atoms. Then you can get the write answer.

5 0

3 years ago

Read 2 more answers

The density of methanol is 0.787 g/ml. What is the mass in grams of 25.0 ml of methanol? Give your answer with the correct unit

Sveta_85 [38]

Answer:

19.6 g is the mass of methanol

Explanation:

Density of methanol is 0.787 g/mL.

Density means mass / volume

Methanol density = Methanol mass / Methanol volume.

Let's replace in the formula

0.787 g/mL = Methanol mass / 25 mL

0.787 g/mL . 25 mL = Methanol mass → 19.6 g

8 0

3 years ago