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3 years ago

Calcium phosphorus magnesium and fluoride mainly serve as structural components of

1 answer:

5 0

The answer to this question would be: bones and teeth

Bones and teeth are made of calcium and fluoride. This makes the bone and teeth sturdy and able to take much more force. Bones are used to be the body framework and teeth is used to digest food. When the level of calcium in the blood is too low, the calcium from bones can be digested by osteoclast to increase the calcium level in the blood.

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1. Who is the father of atomic theory? 2. Who discovered the electron? 3. Who expressed particles by wave equations? 4. Who rese

krek1111 [17]

1. Who is the father of atomic theory?
Dalton

2. Who discovered the electron?
Thomson

3. Who expressed particles by wave equations?
Schrödinger

4. Who researched on radioactivity?
Curie

5. Who discovered the "open spaces" model?
Rutherford

6. Who applied quantum theory to atoms?
Bohr

6 0

4 years ago

Read 2 more answers

Antimony has two naturally occuring isotopes, 121 Sb and 123 Sb . 121 Sb has an atomic mass of 120.9038 u , and 123 Sb has an at

valina [46]

Answer:

Percentage abundance of 121 Sb is = 57.2 %

Percentage abundance of 123 Sb is = 42.8 %

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.

For first isotope, 121 Sb :

% = x %

Mass = 120.9038 u

For second isotope, 123 Sb:

% = 100 - x

Mass = 122.9042 u

Given, Average Mass = 121.7601 u

Thus,

$121.7601=\frac{x}{100}\times 120.9038+\frac{100-x}{100}\times 122.9042$

$120.9038x+122.9042\left(100-x\right)=12176.01$

Solving for x, we get that:

x = 57.2 %

Thus, percentage abundance of 121 Sb is = 57.2 %

percentage abundance of 123 Sb is = 100 - 57.2 % = 42.8 %

6 0

3 years ago

Help me. ASAP!!!!! 23 POINTS!!!!!!!

Alona [7]

a) Group 2 elements have 2 electrons on their outer shell, so they form a 2+ charge.

b) they lose 2 electrons as they are transferred to the non metal.

c)They obtain this charge as when they are made into an ionic compound the 2 electrons on the outer shell are transferred to the non metal, meaning there are 2 more protons that electrons, giving it a positive charge.

hope this helps! :)

6 0

3 years ago

Use the Activity Series Chart

omeli [17]

Answer:

Explanation:

Mg is above Al on the table meaning it is easier to oxidize.

Fe and Zn are below Al on the table showing they are not as reactive.

8 0

3 years ago

Given that the free energy of the twist-boat conformer of cyclohexane is 5.3 kcal/mol greater than that of the chair conformer,

marishachu [46]

Answer:

0.013%

Yes, it does. The answer agrees with the statement.

Explanation:

Both conformers are in equilibrium, and it can be represented by the equilibrium equation K:

K = [twist-boat]/[chair]

The free energy between them can be calculated by:

ΔG° = -RTlnK

Where R is the gas constant (8.314 J/mol.K), and T is the temperature (25°C + 273 = 298 K).

ΔG° = 5.3 kcal/mol * 4.182 kJ/kcal = 22.165 kJ/mol = 22165 J/mol

22165 = -8.314*298*lnK

-2477.572lnK = 22165

lnK = -8.946

K = $e^{-8.946}$

K = 1.30x10⁻⁴

[twist-boat]/[chair] = 1.30x10⁻⁴

[twist-boat] = 1.30x10⁻⁴[chair]

The percentage of the twist-boat conformer is:

[twist-boat]/([twist-boat] + [chair]) * 100%

1.30x10⁻⁴[chair]/(1.30x10⁻⁴[chair] + [chair]) *100%

0.013%

The statement about the conformers is that the chair conformer is more stable, and because of that is more present. So, the answer agrees with it.

3 0

3 years ago