Answer:
Q = 44.9 j
Explanation:
Mass of iron = 5.0 g
Change in temperature = 20 °C
Specific heat of iron = 0.449 j/g.°C
Heat transferred = ?
Formula:
<em>Q = m.c. ΔT
</em>
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Solution:
<em>Q = m.c. ΔT
</em>
Q = 5 g × 0.449 j/g.°C × 20 °C
Q = 44.9 j
Δ H reaction = q / n where q: amount of heat released and n is number of moles of substance.
q = m . C . ΔT where:
m = mass of substance (g)
C = Specific heat capacity (4.18)
ΔT = change in temperature = 24.25 - 23.16 = 1.09
q = 1000 x 4.18 x 1.09 = 4556 J = 4.556 kJ
number of moles (n) = Molarity (M) x Volume (L)
= 0.185 M x 0.07 L = 0.01295 mole
Δ H = q / n = - (4.556 kJ / 0.01295 mole) = -351.8 kJ / mol
Note: it is exothermic reaction (-ve sign) i.e. temperature is raised
A. Chocolate syrup dissolve in milk because the milk is changing
