An alpha particle is equivalent to a _____ nucleus.
2 answers:
Answer: B. helium
Explanation:
Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.
General representation of an element is given as: where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
As the alpha particle has atomic number of 2 and mass number of 4, this is helium nuclei.
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Answer:
of neon
at
and
(the second choice) would contain an equal number of gas particles as
of
at
and
(assuming that all four gas samples behave like ideal gases.)
Explanation:
By Avogadro's Law, if the temperature and pressure of two ideal gases is the same, the number of gas particles in each gas would be proportional to the volume of that gas.
All four gas samples in this question share the same temperature and pressure. Hence, if all these gases are ideal gases, the number of gas particles in each sample would be proportional to the volume of that sample. Two of these samples would contain the same number of gas particles if and only if the volume of the two samples is equal to one another.
The second choice, of neon
at
and
, is the only choice where the volume of the sample is also
. Hence, that choice would be the only one with as many gas particles as
of
at
and
.
Answer:
Ka = 6.02x10⁻⁶
Explanation:
The equilibrium that takes place is:
- HA ⇄ H⁺ + A⁻
- Ka = [H⁺][A⁻]/[HA]
We <u>calculate [H⁺] from the pH</u>:
- pH = -log[H⁺]
- [H⁺] =
- [H⁺] = 9.12x10⁻⁴ M
Keep in mind that [H⁺]=[A⁻].
As for [HA], we know the acid is 0.66% dissociated, in other words:
- [HA] * 0.66/100 = [H⁺]
We <u>calculate [HA]</u>:
- [HA] = 0.138 M
Finally we <u>calculate the Ka</u>:
- Ka =
= 6.02x10⁻⁶