A sample of 28 Mg decays initially at a rate of 53500 disintegrations per minute, but the decay rate falls to 10980 disintegrati
1 answer:
Answer : The half life of 28-Mg in hours is, 6.94
Explanation :
First we have to calculate the rate constant.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time passed by the sample = 48.0 hr
a = initial amount of the reactant disintegrate = 53500
a - x = amount left after decay process disintegrate = 53500 - 10980 = 42520
Now put all the given values in above equation, we get
Now we have to calculate the half-life.
Therefore, the half life of 28-Mg in hours is, 6.94
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Answer:
-241.826 kJ·mol⁻¹; -146.9 J·K⁻¹mol⁻¹; 664.6 J·K⁻¹mol⁻¹; spontaneous
Explanation:
½O₂(g) + H₂(g) ⟶ H₂O(g)
ΔHf°/kJ·mol⁻¹: 0 0 -241.826
S°/J·K⁻¹mol⁻¹: 205.0 130.6 188.7
1. ΔᵣH
ΔᵣH = products -reactants = -241.826 -(0 + 0) = -241.826 kJ·mol⁻¹
2. ΔᵣS
ΔᵣS = products - reactants = 188.7 - (205.0 + 130.6) = 188.7 - 335.6 = -146.9 J·K⁻¹mol⁻¹
3. ΔS(univ)
4. Spontaneity
ΔG is negative, so the reaction is spontaneous.
Answer:
This question is incomplete but the completed question is in the attachment below. And the correct is b
Explanation:
Specific heat capacity can be defined as the amount of heat required to raise to raise 1 kg of a substance by 1 kelvin. Thus, this means that when the specific heat capacity of a substance is high, it takes more energy to increase the temperature of that substance. This also means that when different substances are subjected to the same amount of heat, the substance with the higher specific heat capacity will absorb less heat; for example at a beach, water has a very high specific heat capacity, thus when the sand in the beach is hot, the beach water is still relatively cold.
From the description above, <u>it can be seen that the metal with the least specific capacity will absorb the greatest amount of heat, thus the metal is lead</u> with the specific heat capacity of 0.129 J/(g. °C).
