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3 years ago

How many neutrons does an element have if its atomic number is 40 and its mass number is 154

Chemistry

1 answer:

kramer3 years ago

4 0

I am not sure about this answer 194

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ΔH for the reaction below is -826.0 kJ/mol. Calculate the heat change when a 69.03-g sample of iron is reacted.4Fe(s) + 3 O2(g)

Anuta_ua [19.1K]

Answer:

c. -1020.9 kJ

Explanation:

4Fe (s) + 3 O₂ (g) --> 2 Fe₂O₃(s) ΔH = -826.0 kJ/mol.

atomic weight of iron = 56

69.03 g = 69.03 / 56

= 1.23268 moles

Heat released by 1.23268 moles

= 1.23268 x 826.0

= -1020.9 kJ .

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3 years ago

Which properties result from minimal interactions between molecules in a gas?

7nadin3 [17]

The liquids so play tank i am just completing my sdgsgr

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3 years ago

What is the classification of a solution of naoh with a ph of 8.3?

Maksim231197 [3]

Answer:

Alkaline or basic solution (alkaline and basic means the same)

Explanation:

According to the pH, solutions may be classified as neutral, acidic, or alkaline (basic).

This table shows such classification:

pH classification

7 neutral

> 7 alkaline or basic

< 7 acidic

Thus, since the pH of the solution is 8.3, which is greater than 7, the solution is classified as basic (alkaline).

Additionally, you must learn that pH is a logarithmic scale for the concentration of hydronium ions in the solution.

pH = - log [H₃O⁺]

You can calculate the concentration of hydronium ions using antilogarithm properties:

$pH=-log[H_3O^+]\\ \\ {[H_3O^+]}=10^{-pH}\\ \\ {[H_3O^+]}=10^{-8.3}=0.00000000501$

NaOH solutions are alkaline solutions, bases, according to Arrhenius model, because they contain OH⁻ ions and release them when ionize in water.

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ladessa [460]

What do you mean by unlock all of them? Please explain

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** WILL MARK BRAINLIEST **

hram777 [196]

It is c I hope I helped out with this question!.

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