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3 years ago

How many electrons does fluorine have? How many electron shells? How many electrons are needed to fill the valence shell?

Chemistry

1 answer:

Alex17521 [72]3 years ago

7 0

Answer:

9 electrons when there is no charge shown. It has 2 shells, this is easy to see on the periodic table because it is in the second row. Otherwise you can count. There is 2 electrons on the inner shell then every shell after holds 8. Fluorine only has 9 electrons so 2 for the first shell and 7 on the outter shell. It needs 1 more electron to fill its outter (valence) shell.

Explanation:

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for a neutralization reaction, would you expect the magnitude of q to increase, decrease, or stay the same if the concentration

ikadub [295]

For a neutralization reaction, the value of q(heat of neutralization) is doubled when the concentration of only the acid is doubled.

A neutralization reaction is a reaction in which an acid reacts with a base to yield salt and water. Ionically, a neutralization reaction goes as follows; H^+(aq) + OH^-(aq) ------> H20(l).

The heat of neutralization (Q) of the system depends on the concentration of the solutions. Since Q is dependent on concentration, if the concentration of any of the reactants is doubled, more heat is evolved hence Q is doubled.

Learn more: brainly.com/question/10323185

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2 years ago

What do you think is meant by the statement "the digestive system is very different

Kryger [21]

It could possibly refer to “the small intestines absorb most of the nutrients in food, and your circulatory system passes them on to other parts of your body to store or use. Special cells help absorbed nutrients cross intestinal lining into your bloodstream” hope this helps Good luck

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3 years ago

What is the relative atomic mass of a hypothetical element that consists isotopes in the indicated natural abundances

belka [17]

The given question is incomplete. The complete question is:What is the relative atomic mass of a hypothetical element that consists isotopes in the indicated natural abundances.

Isotope mass amu Relative abundance

1 77.9 14.4

2 81.9 14.3

3 85.9 71.3

Express your answer to three significant figures and include the appropriate units.

Answer: 84.2 amu

Explanation:

Mass of isotope 1 = 77.9

% abundance of isotope 1 = 14.4% = $\frac{14.4}{100}=0.144$

Mass of isotope 2 = 81.9

% abundance of isotope 2 = 14.3% = $\frac{14.3}{100}=0.143$

Mass of isotope 3 = 85.9

% abundance of isotope 2 = 71.3% = $\frac{71.3}{100}=0.713$

Formula used for average atomic mass of an element :

$\text{ Average atomic mass of an element}=\sum(\text{atomic mass of an isotopes}\times {{\text { fractional abundance}})$

$A=\sum[(77.9\times 0.144)+(81.9\times 0.143)+(85.9\times 0.713)]$

$A=84.2amu$

Therefore, the average atomic mass of a hypothetical element that consists isotopes in the indicated natural abundances is 84.2 amu

4 0

3 years ago

How much heat is needed to raise the temperature of water with mass of 27.0 g at 20.0°C to 45.0°C?

ohaa [14]

Answer:

2835 J

Explanation:

Take the specific heat capacity of water as 4.2 J/ g°C.

Energy (heat) = mass x specific heat capacity x change in temperature

(E= mcΔT)

E = 27 x 4.2 x (45-20)

E = 2835 J

7 0

3 years ago

Hydrazine (N2H4) is used as rocket fuel. It reacts with oxygen to form nitrogen and water.

Marina86 [1]

Answer:

See explanation below for answers

Explanation:

This is a stochiometry reaction. LEt's write the overall reaction again:

N₂H₄ + O₂ ---------> N₂ + 2H₂O

This reaction is taking place at Standard temperature and pressure conditions (STP) which are P = 1 atm and T = 273 K. To know the volume of N₂ formed, we need to know first how many moles are formed, and this can be calculated with the reagents and the limiting reagent. Let's calculate the moles first of the reagents:

MM N₂H₄ = 32 g/mol; MM O₂ = 32 g/mol

mol N₂H₄ = 2000 / 32 = 62.5 moles

mol O₂ ? 2100 / 32 = 65.63 moles

Now that we have the moles, we need to apply the stochiometry and calculate the limiting reagent. According to the overall reaction we have a mole ratio of 1:1 between N₂H₄ and O₂, therefore:

1 mole N₂H₄ ---------> 1 mole O₂

62.5 moles ----------> X

X = 62.5 moles of O₂

But we have 65.63 moles, therefore, the limiting reactant is the N₂H₄.

We also have a 1:1 mole ratio with the N₂, so:

moles N₂H₄ = moles N₂ = 62.5 moles

Now that we have the moles, we can calculate the volume with the ideal gas equation:

PV = nRT

V = nRT / P

R: gas constant (0.082 L atm / K mol)

Replacing we have:

v = 62.5 * 0.082 * 273 / 1

V = 1399.13 L of N₂

Now, how many grams of the excess remains?, we know how many moles are reacting so, let's see how much is left:

moles remaining = 65.63 - 62.5 = 3.12 moles

then the mass of oxygen:

m = 3.12 * 32 = 100.16 g of O₂

7 0

2 years ago

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