Answer:
The energy required is 3225 Joules.
Explanation:
Given,
mass of lead cube = 500 grams
T₁ = 25°C
T₂ = 75°C
specific heat of lead = 0.129 J/g°C
Energy required to heat the lead can be found by using the formula,
Q = (mass) (ΔT) (Cp)
Here, ΔT = T₂ - T₁ = 75 - 25 = 50
Substituting the values,
Q = (500)(50)(0.129)
Q = 3225 Joules.
Therefore, energy required is 3225 J.
As number of gaseous moles in reactant and prodict are same that is 4
So No change will occur
Answer:
296.1 day.
Explanation:
- The decay of radioactive elements obeys first-order kinetics.
- For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life time of the reaction (t1/2 = 1620 years).
∴ k = ln2/(t1/2) = 0.693/(74.0 days) = 9.365 x 10⁻³ day⁻¹.
- For first-order reaction: <em>kt = lna/(a-x).</em>
where, k is the rate constant of the reaction (k = 9.365 x 10⁻³ day⁻¹).
t is the time of the reaction (t = ??? day).
a is the initial concentration of Ir-192 (a = 560.0 dpm).
(a-x) is the remaining concentration of Ir-192 (a -x = 35.0 dpm).
<em>∴ kt = lna/(a-x)</em>
(9.365 x 10⁻³ day⁻¹)(t) = ln(560.0 dpm)/(35.0 dpm).
(9.365 x 10⁻³ day⁻¹)(t) = 2.773.
<em>∴ t </em>= (2.773)/(9.365 x 10⁻³ day⁻¹) =<em> 296.1 day.</em>
Specific heat is the amount of heat absorb or released by a substance to change the temperature to one degree Celsius. To determine the specific heat, we use the expression for the heat absorbed by the system. Heat gained or absorbed in a system can be calculated by multiplying the given mass to the specific heat capacity of the substance and the temperature difference. It is expressed as follows:
Heat = mC(T2-T1)
By substituting the given values, we can calculate for C which is the specific heat of the material.
2510 J = .158 kg ( 1000 g / 1 kg) (C) ( 61.0 - 32.0 °C)C = 0.5478 J / g °C
