Under what circumstances might be important to know the activity tendencies of elements?
1 answer:
Answer: It is very important to know the activity tendencies of the elements. The activity tendencies tells us about whether the element is reactive or not.
In the redox-reaction where there is a need to know the oxidizing agent and reducing agent, we can know it easily from the activity tendencies. The elements lying above the reactivity series are better reducing agents.
In the substitution reactions, the activity tendencies helps us to know which element will replace the other. The element lying above in the series will replace the element lying below it.
where, N is an element that lies above in the reactivity series
M is an element that lies below in the reactivity series
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Answer:
Explanation:
This is a problem in calorimetry — the measurement of the quantities of heat that flow from one object to another.
It is based on the Law of Conservation of Energy — Energy can be transformed from one type to another, but it cannot be destroyed or created.
If heat flows out of the reactor (negative), the same amount of heat must flow into the water (positive).
Since there is no change in total energy,
heat₁ + heat₂ = 0
The symbol for the quantity of heat transferred is q, so we can rewrite the word equation as
q₁ + q₂ = 0
The formula for the heat absorbed or released by an object is
q = mCΔT, where
m = the mass of the sample
C = the specific heat capacity of the sample, and
ΔT = T_f - T_i = the change in temperature
1. Equation
There are two heat flows in this problem,
heat released by reactor + heat absorbed by water = 0
q₁ + q₂ = 0
q₁ + m₂C₂ΔT₂ = 0
2. Data:
q₁ = -23 746 kJ
m₂ = ?; C₂ = 4.184 J°C⁻¹g⁻¹; T_f = 95 °C; T_i = 10 °C
3. Calculations
(a) Convert kilojoules to joules
(b) ΔT
ΔT₂ = T_f - T_i = 95 °C - 10 °C = 85 °C
(c) m₂