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3 years ago

Consider the reaction pathway graph below.

Chemistry

2 answers:

bagirrra123 [75]3 years ago

8 0

<u>Answer:</u> The correct answer is E and D.

<u>Explanation:</u>

$\Delta H$ is defined as the difference in the total energy of the products to the total energy of the reactants. It is negative for exothermic reactions and positive for endothermic reactions.

Equation used to represent this quantity follows:

$\Delta H=H_{products}-H_{reactants}$

From the given graph,

The starting point of the reaction is represented by the line E, which is the energy of the reactants and the ending point of the reaction is represented by the line D which is the energy of the products.

$\Delta H=H_{D}-H_{E}$

As, the energy of the products is lower than the energy of the reactants. Hence, this reaction is a type of exothermic reactions.

Therefore, the correct answer is E and D.

Artemon [7]3 years ago

3 0

E and Dis determine the H

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4 years ago

Read 2 more answers

Nitrogen dioxide is used industrially to produce nitric acid, but it contributes to acid rain and photochemical smog. What volum

Strike441 [17]

Answer:

35.41 L

Explanation:

Given, Volume of Copper = 4.84 cm³

Density = 8.95 g/cm³

Considering the expression for density as:

$Density=\frac {Mass}{Volume}$

So,

So, Mass= Density Volume = 8.95 g/cm³ 4.84 cm³ = 43.318 g

Mass of copper = 43.318 g

Molar mass of copper = 63.546 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{43.318\ g}{63.546\ g/mol}$

Moles of copper = 0.6817 moles

Given, Volume of nitric acid solution = 227 mL = 227 cm³

Density = 1.42 g/cm³

Considering the expression for density as:

$Density=\frac {Mass}{Volume}$

So,

So, Mass= Density Volume = 1.42 g/cm³ 227 cm³ = 322.34 g

Also, Nitric acid is 68.0 % by mass. So,

Mass of nitric acid = $\frac {68}{100}\times 322.34\ g$ = 219.1912 g

Molar mass of nitric acid = 63.01 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{219.1912\ g}{63.01\ g/mol}$

Moles of nitric acid = 3.4786 moles

According to the reaction,

$Cu_{(s)}+4HNO_3_{(aq)}\rightarrow Cu(NO_3)_2_{(aq)} + 2NO_2_{(g)} + 2H_2O_{(l)}$

1 mole of copper react with 4 moles of nitric acid

Thus,

0.6817 moles of copper react with 4*0.6817 moles of nitric acid

Moles of nitric acid required = 2.7268 moles

Available moles of nitric acid = 3.4786 moles

Limiting reagent is the one which is present in small amount. Thus, nitric acid is present in large amount, copper is the limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of copper on reaction forms 2 moles of nitrogen dioxide

So,

0.6817 mole of copper on reaction forms 2*0.6817 moles of nitrogen dioxide

Moles of nitrogen dioxide = 1.3634 moles

Given:

Pressure = 724 torr

The conversion of P(torr) to P(atm) is shown below:

$P(torr)=\frac {1}{760}\times P(atm)$

So,

Pressure = 724 / 760 atm = 0.9526 atm

Temperature = 28.2 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (28.2 + 273.15) K = 301.35 K

Using ideal gas equation as:

PV=nRT

where,

P is the pressure

V is the volume

n is the number of moles

T is the temperature

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

0.9526 atm × V = 1.3634 mol × 0.0821 L.atm/K.mol × 301.35 K

⇒V = 35.41 L

3 0

3 years ago

Compare and contrast magma and lava

motikmotik

Magma and lava are words that are used in relation to rock formation. Magma refers to melted rock, that is rock in liquid form, which is found in the earth's crust. The lava on the other hand to the magma which has escaped from the earth crust and has moved to the surface via volcano vent. Thus. magma and lava both refer to molten rock, but magma refers to the molten rock that is found underneath the earth while lava refer to the molten rock that is found on the earth surface; that is the difference between them.

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4 years ago

In this equation, what should be the coefficients of the reactants and products? I2 + O2 → I4O9

denpristay [2]

4I₂+9O₂= 2I₄+2O₉
Reactants: 8 iodine, 18 oxygen
Products: 8 iodine, 18 oxygen
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3 years ago

Compare and contrast the atomic structures of helium and lithium at room temperature

kykrilka [37]

Answer:

How is it possible that helium, having 2 protons, and lithium, having 3 protons, are so different in terms of their physical properties? How come one is a gas at room temperature and the other is a solid metal?

Then why lithium and beryllium, the latter having 1 proton more than the former, are both metals and solids at room temperature?

Now if you remove neutrons from the nuclei of any element (except hydrogen), they form isotopes that have similar chemical properties and different physical properties, while still being an atom of the same element - therefore the protons, if I understand it correctly, are what determine whether an element is a gas or a solid at room temperature, and not the neutrons (or even electrons). Is this true?

The deeper question is that why do the properties of elements and their atoms change significantly - in some cases as with helium and lithium - just by having an additional proton in their nucleus, if the fundamental building blocks of protons (quarks) are identical for each proton? Then in the case of lithium and beryllium, why is the change in physical properties so subtle compared to the first case?

Edit

This question has already been asked before, however I am specifically interested in helium and lithium - why is one a gas and the other a solid metal at room temperature, having completely different chemical and physical properties? Is this a result of the electron shell configuration? Why does an extra proton, neutron and electron give rise to such a difference?

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3 years ago