Isotopes of same element has different number of neutrons with different masses and having same number of protons and electrons.
Radioactive isotopes are those isotopes which are radioactive in nature. The unstable nucleus results in the radioactivity process and this process will go on until the stable isotope (element) forms.
Thus, the nucleus of unstable isotopes of an element will decay leading to emission of radiation.
Answer:
ΔHr = -103,4 kcal/mol
Explanation:
<u>Using:</u>
<u>AH° (kcal/mol)
</u>
<u>Metano (CH)
</u>
<u>-17,9
</u>
<u>Cloro (CI)
</u>
<u>tetraclorometano (CCI)
</u>
<u>- 33,3
</u>
<u>Acido cloridrico (HCI)
</u>
<u>-22</u>
It is possible to obtain the ΔH of a reaction from ΔH's of formation for each compound, thus:
ΔHr = (ΔH products - ΔH reactants)
For the reaction:
CH₄(g) + Cl₂(g) → CCl₄(g) + HCl(g)
The balanced reaction is:
CH₄(g) + 4Cl₂(g) → CCl₄(g) + 4HCl(g)
The ΔH's of formation for these compounds are:
ΔH CH₄(g): -17,9 kcal/mol
ΔH Cl₂(g): 0 kcal/mol
ΔH CCl₄(g): -33,3 kcal/mol
ΔH HCl(g): -22 kcal/mol
The ΔHr is:
-33,3 kcal/mol × 1 mol + -22 kcal/mol× 4 mol - (-17,9 kcal/mol × 1 mol + 0kcal/mol × 4mol)
<em>ΔHr = -103,4 kcal/mol</em>
<em></em>
I hope it helps!
<h3>
Answer:</h3>
812 kPa
<h3>
Explanation:</h3>
- According to Boyle's law pressure and volume of a fixed mass are inversely proportional at constant absolute temperature.
- Mathematically,
At varying pressure and volume;
P1V1=P2V2
In this case;
Initial volume, V1 = 2.0 L
Initial pressure, P1 = 101.5 kPa
Final volume, V1 = 0.25 L
We are required to determine the new pressure;
Replacing the known variables with the values;
= 812 kPa
Thus, the pressure of air inside the balloon after squeezing is 812 kPa
Answer:
The bohr model is the model in use today
Answer : The correct option is (C) : Dew forms on grass when water vapor forms when molecules cool and join together.
Explanation :
Air contains a small amount of water vapors. When the temperature of an object is lowered than the ambient temperature, the vapors get condensed and small water droplets are formed on the object.
During night time, when the temperature is lowered, the blades of grass become cool. As a result, the vapor molecules slow down and eventually come close to each other. They join together to form liquid water which gets deposited on the blades in the form of dew drops.
The only option that explains this process is option C.
