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Which of the following is an endothermic reaction?. . A) an explosion. B) condensation of steam. C) freezing water. D) thawing i

Bezzdna [24]

Endothermic reaction : A reaction in which the system absorb energy, usually in the form of heat

the one that is an endothermic reaction is : D. Thawing ice

hope this helps

7 0

2 years ago

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A sample of O2 gas (2.0 mmol) effused through a pinhole in 5.0 s. It will take __________ s for the same amount of CO2 to effuse

ludmilkaskok [199]

Answer:

$\large \boxed{\text{5.9 s}}$

Explanation:

Graham’s Law applies to the effusion of gases:

The rate of effusion (r) of a gas is inversely proportional to the square root of its molar mass (M).

$r \propto \dfrac{1}{\sqrt{M}}$

If you have two gases, the ratio of their rates of effusion is

$\dfrac{r_{2}}{r_{1}} = \sqrt{\dfrac{M_{1}}{M_{2}}}$

The time for diffusion is inversely proportional to the rate.

$\dfrac{t_{2}}{t_{1}} = \sqrt{\dfrac{M_{2}}{M_{1}}}$

Let CO₂ be Gas 1 and O₂ be Gas 2

Data:

M₁ = 44.01

M₂ = 32.00

Calculation

$\begin{array}{rcl}\dfrac{t_{2}}{t_{1}} & = & \sqrt{\dfrac{M_{2}}{M_{1}}}\\\\\dfrac{t_{2}}{\text{5 s}}& = & \sqrt{\dfrac{44.01}{32.00}}\\\\& = & \sqrt{1.375}\\t_{2}& = & \text{5 s}\times 1.173\\& = & \mathbf{5.9 s} \\\end{array}\\\text{It will take $\large \boxed{\textbf{5.9 s}}$ for the carbon dioxide to effuse.}$

4 0

2 years ago

The substance whose lewis structure shows three covalent bonds is

Gnoma [55]

The substance whose Lewis structure shows three covalent bonds is Nitrogen gas molecule.

<h3>What is Lewis structure?</h3>

Lewis structure is a dot structure which gives idea about the number of valence electrons that are involved in the bonding within the molecule.

Lewis dot structure of nitrogen gas will be expressed as in the attached image, where between two nitrogen atoms triple bond is present. That triple bond is formed by the sharing of electrons and known as covalent bonds.

Hence in nitrogen gas molecule three covalent bonds is present.

To know more about Lewis structure, visit the below link:
brainly.com/question/21026664

#SPJ4

4 0

2 years ago

Methane undergoes combustion. Which products form?

Aleksandr [31]

Methane is a carbon compound which undergoes combustion to release energy and form bi production which are Carbon dioxide ( CO2 ) and  Water ( H20 ).

the balanced chemical equation for the reaction is : -

CH4 + 2 O2 =》CO2 + 2 H2O

3 0

2 years ago

Uranium-236 is _____. created by fusion reactions an unstable isotope of uranium created from four hydrogen atoms used in the H-

nata0808 [166]

Uranium-236 is intermediate nuclei. created by fusion reactions an unstable isotope of uranium created from four hydrogen atoms used in the H-bomb.

Following is the reaction involved in above process:

 $^{235}U$ + $^{1}n$ → $^{236}U$ → $^{144}Ba$ + $^{89}Kr$ + 3 $^{1}n$ + 177 MeV

Here,
$^{235}U$ = Fission material,
$^{1}n$ = projectile,
$^{236}U$ = intermediate nuclei,
$^{144}Ba$ and $^{89}Kr$ = Fission product

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2 years ago

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