Answer:
Q = 1147.5 cal
Explanation:
Given data:
Energy absorbed = ?
Mass of water = 75 g
Initial temperature = 22.5°C
Final temperature = 37.8°C
Specific heat of water = 1 cal/g.°C
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2- T1
ΔT = 37.8°C - 22.5°C
ΔT = 15.3 °C
Q = m.c. ΔT
Q = 75 g . 1 cal/g.°C . 15.3 °C
Q = 1147.5 cal
The statement is true. If a mineral lacks the presence of iron in it then it will be generally dimagnetic. It means non iron minerals do not show magnetic property in general. There are some minerals like serpentine do show some magnetic susceptibility, however this is negligible as compared to iron minerals hence the ores with no magnetic are generally diamagnetic.
Answer:
269.068 kJ/mol.
Explanation:
<em>ln (k₂/k₁) = (Eₐ/R) [(T₂ - T₁)/(T₁T₂)].</em>
<em>k₁ = 6.20 x 10⁻⁴ min⁻¹, T₁ = 700.0 K.</em>
<u><em>To get k₂:</em></u>
in first order reactions: k = 0.693/(half-life).
∴ k₂ = 0.693/(29.0 min) = 2.39 x 10⁻² min⁻¹, T₂ = 760.0 K.
∵ ln (k₂/k₁) = (Eₐ/R) [(T₂ - T₁)/(T₁T₂)]
∴ ln [(2.39 x 10⁻² min⁻¹)/(6.20 x 10⁻⁴ min⁻¹)] = (Eₐ/(8.314 J/mol.K)) [(760.0 K - 700.0 K) / (760.0 K)(700.0 K)].
3.65 = (Eₐ/(8.314 J/mol.K)) (1.128 x 10⁻⁴).
<em>∴ Eₐ =</em> (3.65)(8.314 J/mol.K) / (1.128 x 10⁻⁴) = <em>269.068 kJ/mol.</em>