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malfutka [58]
3 years ago
5

A single atom of an element has 21 nutrons 20 electtons and 20 protons which element is it

Chemistry
1 answer:
guajiro [1.7K]3 years ago
7 0

your element would be calcium


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In the following reaction, what is the quantity of heat (in kJ) released when 5.87 moles of CH₄ are burned?
IRISSAK [1]

Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.

The enthalpy of a chemical reaction as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.

The enthalpy is an extensive property, that is, it depends on the amount of matter present.

In this case, the balanced reaction is:

CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g)

and the enthalpy reaction ∆H° has a value of -802 kJ/mol.

This equation indicates that when 1 mole of CH₄ reacts with 2 moles of O2, 802 kJ of heat is released.

When 5.87 moles of CH₄ are burned, then you can apply the following rule of three: if 1 mole of CH₄ releases 802 kJ of heat, 5.87 moles of CH₄ releases how much heat?

heat=\frac{5.87 molesof CH_{4}x802 kJ}{1 mol of CH_{4} }

<u><em>heat= 4,707.74 kJ</em></u>

Finally, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.

Learn more:

  • brainly.com/question/15355361?referrer=searchResults
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5 0
2 years ago
calculate the speed of an electron if its de broglie wavelength is twice its displacement in one second
valkas [14]

Answer:

The speed of an electron is 0.01908 m/s.

Explanation:

De-Broglie wavelength is given by:

\lambda=\frac{h}{mv}

where,  \lambda = wavelength of a particle

h = Planck's constant = 6.626\times 10^{-34}Js

m = mass of particle

v = velocity of the particle

Velocity of an electron = v

Mass of an electron = 9.1\times 10^{-31}kg

Wavelength of electron is twice the displacement in seconds which is velocity of an electron.

Then.wavelength of an electron = \lambda =2v

\lambda =2v=\frac{6.626\times 10^{-34}Js}{9.1\times 10^{-31}kg\times v}

v = 0.01908 m/s

The speed of an electron is 0.01908 m/s.

5 0
3 years ago
PLS HELP A gas has a volume of 250 mL at 96.5 kPa. What will the pressure of the gas be if the
ella [17]

Answer:

Solve the following problems (assuming constant temperature). Assume all numbers are 3 sig figs. 1. A sample of oxygen gas occupies a volume of 250 mL at 740 torr pressure. ... the gas exert if the volume was decreased to 2.00 liters? ... A 175 mL sample of neon had its pressure changed from 75.0 kPa to 150 kPa.

Explanation:

8 0
3 years ago
Is it possible for a balloon with an initial internal pressure equal to 250.0 kPa
MrRa [10]
No, don't try, it will explode  close to 187 kPa
6 0
3 years ago
What would make bromide salt insoluble in water?
anzhelika [568]
Its doesn't dissolve in water! 
3 0
3 years ago
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