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2 years ago

How can the total valence electrons for an element be determined? Explain.

Chemistry

1 answer:

kramer2 years ago

7 0

Answer:

To find how many valence electrons are in an element, simply locate the column number that it is in, and that determines the number of valence electrons in an element.

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What type of system is Earth ?

Gnoma [55]

The planet Earth itself is considered to be a closed system because there is a limit to the amount of matter that is exchanged. However, there are open systems that are ON Earth.

3 0

3 years ago

d) A short ton of coal holds about 2.24 x 107 J of energy and costs about $56.45 per short ton. How many Joules of energy in the

Feliz [49]

Answer:

396811.337 J

Explanation:

The cost of one short ton of coal = $56.45

The energy related to the short ton of coal = $2.24\times 10^{7}\ J$

Thus, As according to the question,

$56.45 of coal have $2.24\times 10^{7}\ J$ of energy.

$1 of coal have $\frac{2.24\times 10^{7}}{56.45}\ J$ of energy.

<u>The amount of energy = 396811.337 J</u>

4 0

3 years ago

if i add 25 ml of water to 135 ml of a 0.25 M NaOH solution what will the molarity of the diluted solution be

DENIUS [597]

Answer:

0.21 M. (2 sig. fig.)

Explanation:

The molarity of a solution is the number of moles of the solute in each liter of the solution. The unit for molarity is M. One M equals to one mole per liter.

How many moles of NaOH in the original solution?

$n = c \cdot V$ ,

where

$n$ is the number of moles of the solute in the solution.
$c$ is the concentration of the solution. $c = 0.25 \;\text{M} = 0.25\;\text{mol}\cdot\textbf{L}^{-1}$ for the initial solution.
$V$ is the volume of the solution. For the initial solution, $V = 135\;\textbf{mL} = 0.135\;\textbf{L}$ for the initial solution.

$n = c\cdot V = 0.25\;\text{mol}\cdot\textbf{L}^{-1} \times 0.135\;\textbf{L} = 0.03375\;\text{mol}$ .

What's the concentration of the diluted solution?

$\displaystyle c = \frac{n}{V}$ .

$n$ is the number of solute in the solution. Diluting the solution does not influence the value of $n$ . $n = 0.03375\;\text{mol}$ for the diluted solution.
Volume of the diluted solution: $25\;\text{mL} + 135\;\text{mL} = 160\;\textbf{mL} = 0.160\;\textbf{L}$ .

Concentration of the diluted solution:

$\displaystyle c = \frac{n}{V} = \frac{0.03375\;\text{mol}}{0.160\;\textbf{L}} = 0.021\;\text{mol}\cdot\textbf{L}^{-1} = 0.021\;\text{M}$ .

The least significant number in the question comes with 2 sig. fig. Keep more sig. fig. than that in calculations but round the final result to 2 sig. fig. Hence the result: 0.021 M.

8 0

3 years ago

Read 2 more answers

Số oxi hóa của các nguyên tố: Fe(OH)2; Fe(OH)3; FexOy; Zn(OH)2 là gì

BARSIC [14]

Answer:

esfsef

Explanation:

esfsefseF

7 0

2 years ago

You are separating anthracene from benzoic acid via an extraction between ethyl acetate and a basic aqueous solution in a separa

anygoal [31]

The benzoic acid Collect the top layer dry with Na2SO4 and evaporate the solvent.

Benzoic acid is sparingly soluble in water and forms a precipitate. The benzoic acid can then be separated by suction filtration through a Buchner funnel. Washing with sodium bicarbonate converts the benzoic acid to the more water-soluble form of sodium benzoate, which is extracted into the aqueous layer. Additionally, sodium bicarbonate neutralizes the catalytic acid in this reaction.

Benzoic acid containing the naphthalene impurity can be purified by crystallization in water. The reaction between benzoic acid and NaOH is an acid-base neutralization reaction. An acid reacts with a base to form salt and water. In aqueous solutions, NaOH increases the solubility of benzoic acid. Benzoic acid cannot move from one layer to another because ethanol is immiscible with water.

Learn more about Benzoic acid here:-brainly.com/question/28299797

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4 0

1 year ago