Which of the three components of the atom has the smallest mass?

What is covalent bond????

adell [148]

Explanation:

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms

4 0

2 years ago

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How many variables are there in science

Sedaia [141]

There are three variables independent, dependent ,and controlled

7 0

2 years ago

The activation energy for a reaction is changed from 184 kJ/mol to 59.0 kJ/mol at 600. K by the introduction of a catalyst. If t

11111nata11111 [884]

Answer:

The catalyzed reaction will take 2.85 seconds to occur.

Explanation:

The activation energy of a reaction is given by:

$k = Ae^{-\frac{E_{a}}{RT}}$

For the reaction without catalyst we have:

$k_{1} = Ae^{-\frac{E_{a_{1}}}{RT}}$ (1)

And for the reaction with the catalyst:

$k_{2} = Ae^{-\frac{E_{a_{2}}}{RT}}$ (2)

Assuming that frequency factor (A) and the temperature (T) are constant, by dividing equation (1) with equation (2) we have:

$\frac{k_{1}}{k_{2}} = \frac{Ae^{-\frac{E_{a_{1}}}{RT}}}{Ae^{-\frac{E_{a_{2}}}{RT}}}$

$\frac{k_{1}}{k_{2}} = e^{\frac{E_{a_{2}} - E_{a_{1}}}{RT}$

$\frac{k_{1}}{k_{2}} = e^{\frac{59.0 \cdot 10^{3}J/mol - 184 \cdot 10^{3} J/mol}{8.314 J/Kmol*600 K} = 1.31 \cdot 10^{-11}$

Since the reaction rate is related to the time as follow:

$k = \frac{\Delta [R]}{t}$

And assuming that the initial concentrations ([R]) are the same, we have:

$\frac{k_{1}}{k_{2}} = \frac{\Delta [R]/t_{1}}{\Delta [R]/t_{2}}$

$\frac{k_{1}}{k_{2}} = \frac{t_{2}}{t_{1}}$

$t_{2} = t_{1}\frac{k_{1}}{k_{2}} = 6900 y*1.31 \cdot 10^{-11} = 9.04 \cdot 10^{-8} y*\frac{365 d}{1 y}*\frac{24 h}{1 d}*\frac{3600 s}{1 h} = 2.85 s$

Therefore, the catalyzed reaction will take 2.85 seconds to occur.

I hope it helps you!

4 0

2 years ago

A sample of rubidium contains two different isotopes. 72.15% of the sample

Leona [35]

Answer:

Average atomic mass = 85.557 amu.

Explanation:

Given data:

Percent abundance of Rb-85 = 72.15%

Percent abundance of Rb-87 = 27.85%

Average atomic mass = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100

Average atomic mass = (72.15×85)+(27.85×87) /100

Average atomic mass = 6132.75 + 2422.95 / 100

Average atomic mass = 8555.7 / 100

Average atomic mass = 85.557 amu.

4 0

2 years ago

Which of the following happens during a lunar eclipse?

Svetlanka [38]

Answer:

a. Earth casts a shadow on the moon.

Explanation:

Lunar eclipse occurs when Earth comes in between sun and moon. The sunlight falling on moon is blocked by Earth and the shadow of earth falls on moon. This happens on full moon day when sun, earth and moon align in one line.The moon passes through the shadow of earth and appears dark.

Thus, the correct option is a.

5 0

2 years ago