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3 years ago

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Why do all humans have similar features? A. They have the same number and kinds of chromosomes. B. They have identical alleles.

C. They have different alleles. D. Their genes do not allow for any variation.

2 answers:

daser333 [38]3 years ago

6 0

The answer is A. They have the same number and kinds of chromosomes.

Serggg [28]3 years ago

4 0

I belive it is a we all have 46 chromosomes.I learned this in sience.

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Can u help me pls I need it now

Juli2301 [7.4K]

noprggnnnhrrhmmyu,myrgekui.y,uythrgewrtytkud

5 0

3 years ago

Why is it logical to assume that they hydrogen ion concentration in an aqueous solution of a strong monoproctic acid equals the

natka813 [3]

It is logical to assume that they hydrogen ion concentration in an aqueous solution of a strong monoproctic acid equals the molarity of the acid because ions which are charged,for example ammonium ion (NH4+), which can be derived by the addition of a proton to a molecular base.

3 0

3 years ago

A hydrogen-like ion is an ion containing only one electron. The energies of the electron in a hydrogen-like ion are given by the

yan [13]

Answer:

The ionization energy (in kJ/mol) of the helium ion is 21,004.73 kJ/mol .

Explanation:

$E_n = -(2.18 10-18 J)\times \frac{Z^2}{n^2}$

Z = atomic mass

n = principal quantum number

Energy of the electron in n=1,

$E_1= -(2.18 10^{-18} J)\times \frac{4^2}{1^2}=-3.488\times 10^{-17} J$

Energy of the electron in n = ∞

$E_{\infty}= -(2.18 10^{-18} J)\times \frac{2^2}{\infty ^2}=0 J$

Ionization energy of the $He^+$ ion:

$I.E=E_{infty}-E_1=0-(-3.488\times 10^{-17} J)=3.488\times 10^{-17} J$

$I.E=3.488\times 10^{-20} kJ$

To convert in into kj/mol multiply it with $N_A=6.022\times 10^{23} mol^{-1}$

$I.E=3.488\times 10^{-20} kJ\times 6.022\times 10^{23} mol^{-1}=21,004.73kJ/mol$

3 0

3 years ago

Read 2 more answers

In which of the following compounds does the carbonyl stretch in the IR spectrum occur at the lowest wavenumber?

klio [65]

Answer:

a. Cyclohexanone

Explanation:

The principle of IR technique is based on the <u>vibration of the bonds</u> by using the energy that is in this region of the electromagnetic spectrum. For each bond, there is <em>a specific energy that generates a specific vibration</em>. In this case, you want to study the vibration that is given in the carbonyl group C=O. Which is located around 1700 cm-1.

Now, we must remember that the <u>lower the wavenumber we will have less energy</u>. So, what we should look for in these molecules, is a carbonyl group in which less energy is needed to vibrate since we look for the molecule with a smaller wavenumber.

If we look at the structure of all the molecules we will find that in the last three we have <u>heteroatoms</u> (atoms different to carbon I hydrogen) on the right side of the carbonyl group. These atoms allow the production of <u>resonance structures</u> which makes the molecule more stable. If the molecule is more stable we will need more energy to make it vibrate and therefore greater wavenumbers.

The molecule that fulfills this condition is the <u>cyclohexanone.</u>

See figure 1

I hope it helps!

4 0

3 years ago

How many protons, electrons, and neutrons does the following isotope contain? ^{18} \text{F}^{-} 18 F −

melomori [17]

Isotope ¹⁸F⁻ contains:
1) p⁺ = 9; number of protons.
Fluorine has a<span>tomic number Z = 9 (total number of protons).
2) e</span>⁻<span> = 10; </span>number of electrons.<span>
In element number of electrons and protons are the same, because element has neutral charge, but because in this example, fluorine is anion with negative charge, it has one electron more.
3) n</span>° = 9; number of neutrons.
<span>Mass number A = 18 is total number of protons and neutrons in a nucleus, so number of neutrons is A-Z = 18-9=9.</span>

8 0

3 years ago