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Mashutka [201]
2 years ago
9

3. The number of electrons and neutrons in an atom are 13 and 14, respectively. Find out the mass number, atomic number, valency

, and symbol of the element.
​
Chemistry
1 answer:
QveST [7]2 years ago
7 0

Answer:

Explanation:

3. The number of electrons and neutrons in an atom are 13 and 14, respectively. Find out the mass number, atomic number, valency, and symbol of the element.

For a neutral atom. number of protons =number of electrons=13

so since atomic number is the number of protons =13

mass number = protons + neutons =14+13 = 27

atomic number 13 is Aluminum (AL-(see periodic table)

The electronic structure for 13 electrons is 1s2s2p63s23p1

so Al has 3 electrons which are VALIENT and can react and when it loses the 3 it will have  CHARGE OF +3

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Explanation:

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The forensic technician at a crime scene has just prepared a luminol stock solution by adding 18.0 g of luminol into a total vol
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Answer:

1.36M

Explanation:

Luminol is a compound having the molecular formula as C8H7N3O2.

To know the molarity of the stock solution of Luminol, we shall carry out the following:

Step 1:

we shall calculate the number of mole in 18g of luminol. This is shown below:

Molar mass of C8H7N3O2 = (12x8) + (7x1 ) + (14x3) + (16x2)

= 96 + 7 + 42 + 32

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Mass of C8H7N3O2 = 18g

Number of mole of C8H7N3O2 =..?

Mole = Mass /Molar Mass

Number of mole of C8H7N3O2 = 18/177 = 0.102 mole.

Step 2:

Conversion of 75.0 mL of H2O to Litre (L).

1000mL = 1L

Therefore, 75mL = 75/1000 = 0.075L

Step 3:

Determination of the molarity of the stock solution of Luminol.

Molarity is simply defined as the mole of solute per unit litre of water. Mathematically, it is represented as:

Molarity = mole /Volume

With the above formula, we can obtain the molarity of the stock solution of Luminol as follow:

Mole of C8H7N3O2 = 0.102 mole

Volume of water = 0.075L

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Molarity = 0.102/0.075

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He reaction produces 1.6 g of gas in 30 seconds.Calculate the mean rate of the reaction in the first 30 seconds.Use the equation
devlian [24]

Answer:

Mean rate of reaction produced = 0.533 g/sec (approx.)

Explanation:

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