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4 years ago

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Which is the definition of an embryo?

1 answer:

REY [17]4 years ago

6 0

A. prenatal stage of a human up to 8 weeks of development after fertilization

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Electric charges that are different.

Mnenie [13.5K]

A.) Attract each other.

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3 years ago

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B) Un changement qui ne modifie pas l'unité de base et les propriétés<br> d'une substance.

Vaselesa [24]

Answer:

b

Explanation:

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3 years ago

Which is the final electron acceptor in the electron transport system of cellular respiration?

frutty [35]

Oxygen.
As Oxygen has the highest electron affinity/ negativity of them all.<span />

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4 years ago

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How is petroleum formed ?<br> (SCIENCE)

SpyIntel [72]

Answer:

Petroleum is a fossil fuel, meaning that it has been created by the decomposition of organic matter over millions of years. Petroleum is formed when large quantities of dead organisms–primarily zooplankton and algae–underneath sedimentary rock are subjected to intense heat and pressure.

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3 years ago

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How is enthalpy used to predict whether a reaction is endothermic or exothermic?

Radda [10]

<u>Answer:</u>

<em> $329.48 KJ/mol$ heat is released by the combustion of $2 mol$ of methane</em>

<u>Explanation:</u>

The value of enthalpy determines whether the reaction is exothermic or endothermic. If the enthalpy change is positive, then the reaction is endothermic (heat or energy released) and if the enthalpy change is negative then the reaction is exothermic (heat or energy absorbed).

$2CH_4(g)+4O_2(g) => 2CO_2(g)+4H_2O(g)$

$\Delta H \ reaction=[ 2(\Delta HfCO_2)+ 4(\Delta HfH_2O)]-[2(\Delta HfCH_4)+4(\Delta HfO_2)]$

= $2 ( -(393.5 KJ)/mol)-[2( -74.6 KJ/mol)+4(-241.82 KJ/mol)]$

$= -787 KJ/mol-[ -149.2 KJ/mol-967.28 KJ/mol]$

$= -787 KJ/mol+1116.48 KJ/mol$

$=329.48 KJ/mol$

<em>In this question, </em><em>the enthalpy of formation</em><em> has positive value and hence the </em><em>reaction is endothermic</em><em> in which the heat is released. </em>

3 0

3 years ago