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2 years ago

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A student is riding his bicycle the 4 km to school from his house. The graph

1 answer:

masya89 [10]2 years ago

4 0

Answer:

Explanation:

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Using standard heats of formation, calculate the standard enthalpy change for the following reaction. 2NH3(g) 3N2O(g)4N2(g) 3H2O

trasher [3.6K]

Answer: $\Delta H^{0} = -879.15 kJ/mol$

Explanation: <u>Heats</u> <u>of</u> <u>formation</u> is the amount of heat necessary to create 1 mol of a compound from its molecular constituents. The basic conditions the substance is formed is at standard conditions: 1 atm and 25°C. Each compound has its own heat of formation per mol of compound (kJ/mol), but to an element is assigned a value of zero.

<u>Standard</u> <u>Enthalpy</u> <u>Change</u> is defined as the heat absorbed or released when a reaction takes place. It can be positive or negative, which means reaction is endothermic or exothermic, respectively.

Enthalpy change is calculated as the difference between the sum of heat formation of products and the sum of heat formation of the reactants:

$\Delta H^{0}=\Sigma H^{0}_{f}_{(products)}-\Sigma H^{0}_{f}_{(reactants)}$

For the reaction

2NH₃ + 3N₂O → 4N₂ + 3H₂O

2(-46.2) + 3(82.05) 4(0) + 3(-241.8)

$\Delta H^{0}=3(-241.8)-[ 2(-46.2)+3(82.05)]$

$\Delta H^{0}=-725.4-153.75$

$\Delta H^{0}=-879.15$

<u>The standard enthalpy change for the reaction is </u> $\Delta H^{0}=-879.15$ <u> kJ</u>

8 0

2 years ago

What kind of bond occurs between two<br> elements sharing three pairs of electrons?

Zigmanuir [339]

Covalent bond i believe

6 0

2 years ago

An open flask sitting in a lab refrigerator looks empty, but it is actually filled with a mixture of gases called air. If the fl

ira [324]

Answer:

9.39 × 10²² molecules

Explanation:

We can find the moles of gases (n) using the ideal gas equation.

P . V = n . R . T

where,

P is the pressure (standard pressure = 1 atm)

V is the volume

R is the ideal gas constant

T is the absolute temperature (standard temperature = 273.15 K)

$n=\frac{P.V}{R.T} =\frac{1atm.3.50L}{(0.08206atm.L/mol.K).273.15K} =0.156mol$

There are 6.02 × 10²³ molecules in 1 mol (Avogadro's number). Then,

$0.156mol.\frac{6.02\times10^{23}molecules}{mol} =9.39\times10^{22}molecules$

4 0

2 years ago

Guys help please!! any five effects of heat!!

Bogdan [553]

${\huge {\underline {\underline {\bold {\blue{Effects \: of \: Heat}}}}}}$

<em>Expansion </em><em>of </em><em>particles</em><em> </em><em>of</em><em> </em><em>substances.</em><em> </em>
<em>Increase</em><em> </em><em>in </em><em>temperature</em><em>.</em>
<em>Change</em><em> </em><em>in </em><em>state</em><em>.</em>
<em>Change</em><em> </em><em>in </em><em>physical</em><em> </em><em>property</em>
<em>It </em><em>may </em><em>bring</em><em> </em><em>out </em><em>chemical</em><em> </em><em>changes</em><em>.</em>

__________________________________

$\tt\underline\orange{hope \: it \: helps}$

3 0

2 years ago

A neutral atom in the ground state of Sulfur has its outer most valence electron in which orbital? f d

Natasha_Volkova [10]

<u>Answer:</u> The outermost valence electron enters the p orbital.

<u>Explanation:</u>

Valence electrons are defined as the electrons which are present in outer most orbital of an atom.

Sulfur is the 16th element of the periodic table having 16 electrons.

Electronic configuration of sulfur atom is $1s^22s^22p^63s^23p^4$

The number of valence electrons are 2 + 4 = 6

These 6 electrons enter s-orbital and p-orbital but the outermost valence electron will enter the p-orbital.

Hence, the outermost valence electron enters p orbital.

3 0

3 years ago