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3 years ago

9

nguyên tử sắt có điện tích hạt nhân là 26+. trong nguyên tử, số hạt mang điện nhiều hơn số hạt không mang điện là 22. Hãy xác đị

nh số khối của nguyên tử sắt

1 answer:

dimaraw [331]3 years ago

8 0

Answer:

I don't know yr language

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When copper oxide is reacted with sulfuric acid, the acid is often gently heated. This is done in order to:

pav-90 [236]

Copper oxide(solid) + Sulphuric Acid (aqueous)-> Copper Sulphate (aqueous)+ Water(liquid)

In equation form:

CuO +H2SO4 -> CuSO4 + H2O

The colour change you will see is black to blue as Copper oxide is usually found as a black powder. Upon the reaction with sulphuric acid it will change to a cyan blue.

If you heat the made solution of copper sulphate, the water will evaporate and you will be left with white anhydrous copper sulphate crystals.

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3 years ago

Como clasificarias la máquina de la siguiente ilustración? tijera

Lina20 [59]

Answer:

<u><em></em></u>

<u><em>máquina simple: palanca</em></u>

Explanation:

En vista de que la pregunta está realizada en español, la respuesta la doy en el mismo lenguage.

La<em> palanca</em> es una máquina simple que consiste en una barra rígida que puede girar alrededor the un punto the pivote.

La forma en que functiona una palanca es que se aplica la ferza en el extremo de la barra que está más alejado del pivote. Este extremo puede desplazarse una larga distancia o arco, con una fuerza pequeña, haciendo que los puntos que están al otro lado del pivote, a una menor distancia de este, se desplacen una distancia o arco menor pero con más fuerza que la aplicada.

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4 years ago

When the equation Sn + HNO₃ → SnO₂ + NO₂ + H₂O is balanced in acidic solution, what is the smallest whole-number coefficient for

balu736 [363]

Answer:

1.

Explanation:

Hello,

In this case, for the given reaction we first assign the oxidation state for each species:

$Sn^0 + H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 + N^{4+}O^{2-}_2 + H^+_2O^-$

Whereas the half reactions are:

$Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-\\\\H^++H^+N^{5+}O^{-2}_3 +1e^-\rightarrow N^{4+}O^{2-}_2+H_2O$

Next, we exchange the transferred electrons:

$1\times(Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-)\\\\4\times (H^++H^+N^{5+}O^{-2}_3 +1e^-\rightarrow N^{4+}O^{2-}_2+H_2O)\\\\\\Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-\\\\4H^++4H^+N^{5+}O^{-2}_3 +4e^-\rightarrow 4N^{4+}O^{2-}_2+4H_2O$

Afterwards, we add them to obtain:

$Sn^0+2H_2O+4H^++4H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 +4H^++4N^{4+}O^{2-}_2+4H_2O$

By adding and subtracting common terms we obtain:

$Sn^0+4H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 +4N^{4+}O^{2-}_2+2H_2O$

Finally, by removing the oxidation states we have:

$Sn + 4HNO_3 \rightarrow SnO_2 + 4NO_2 + 2H_2O$

Therefore, the smallest whole-number coefficient for Sn is 1.

Regards.

6 0

3 years ago

The aldol condensation involves nucleophilic attack of an enolate to a carbonyl. Use the pop-up menus to identify the total numb

Sindrei [870]

Aldol condensation involves the reaction of an acid or base with a carbonyl group producing a nucleophile that attacks another carbonyl compound to yield a β-hydroxyaldehyde or β-hydroxyketone compound.

<h3>What is aldol condensation?</h3>

The aldol condensation is a reaction in organic chemistry in which there is a reaction between an acid or base and a carbonyl group which then serves as the nucleophile that attcks a second carbonyl to yield a β-hydroxyaldehyde or β-hydroxyketone compound.

The aldol condensation may be acid catalysed or base catlysed. The question is incomplete hence the complete mechanimsms can not be decuced.

Learn more about aldol condensation: brainly.com/question/9415260

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2 years ago

What is the acceleration object velocity of +25m/s to rest in 5.0 s

Irina-Kira [14]

The average acceleration is -5.0 m·s⁻².

The formula for acceleration (<em>a</em>) is

$a = \frac{v_{f}- v_{i}}{t}$

$v_{f}$ = 25 m·s⁻¹; $v_{i}$ = 0; $t$ = 5.0 s

∴ $a = \frac{0-25}{5.0}$ = -5.0 m·s⁻²

The negative sign tells you that the object is <em>slowing down</em>, i.e., it is <em>decelerating</em>.

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4 years ago