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Atomic mass of magnesium = (23.99 x 78.99%) + (24.99 x 10.00%) + (25.98 x 11.01%)
= 24.31 g/mol
Answer:
T = 377.2 K, Less than
Explanation:
The thermodynamic quantity used in predicting whether a reaction is spontaneous or not is the gibbs free energy.
It's relationship with ΔH⁰ and ΔS⁰ is given as;
ΔG° = ΔH° - TΔS°
Basically, a negative value of ΔG° means the reaction is spontaeneous.
To obtain the calculated vale of T,
ΔS° = ΔH°/T
T = ΔH° / ΔS°
T = 377.2 K
Let's calculate the value of ΔG° at that temperature.
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 377.2(− 123.8)
ΔG° = 0 (approximately, values are due to the rounding off)
At ΔG° = 0 the reaction is at equilibrium.
To find if the reaction is spontaneous at lower or hugher temperature than the calculated temperature, we would be substituting the value of T with a smaller (random) value and also a larger (random) value.
Larger T (390K)
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 390(− 123.8)
ΔG° = - 46700 + 48,282
ΔG° = 1582 J/mol
Smaller T (350K)
ΔG° = ΔH° - TΔS°
ΔG° = − 46700 - 350(− 123.8)
ΔG° = - 46700 + 43330
ΔG° = -3370J/mol
This means the temperature would be lesser than the calculated value for it to be spontaneus.
The correct option is B AND C.
An isotope is defined as two or more forms of the same element which contain equal number of protons but different number of neutrons in their nuclei, hence they differ in relative atomic mass but not in chemical properties.
Thus, isotopes has the same number of protons but differ in number of neutrons. Due to this fact, isotopes always have the same atomic number but different mass number. You will notice that the atomic number given for elements B and C are the same [101].
<span>During a nuclear reaction, an atom must emit an alpha particle, which consists of 2 protons (positively charged) and 2 neutrons (neutrally charged). Thus, the alpha particle has a charge of +2 (there are no electrons, which are negatively charged, to balance out the two protons). When an atom emits an alpha particle, it will lose this particle, thus losing 2 protons and 2 neutrons as well. Since the atom in the equation goes from 84 protons to 82, and 86 neutrons to 84, it lost 2 protons and 2 neutrons, indicating that it emitted an alpha particle.</span>
