The answer is catalyst.
A catalyst is characterized by acceleration the rate of a chemical reaction but not modifiy the equilibrium, which is what k represents (the constant of equilibrium of the reaction).
The catalyst manages that the reaction goes through a different pathway, with a lower activation energy, so the transition compound is reached faster and the whole reaction goes faster, but the final species and their equilibriium concentrations do not change.
I’m pretty sure it will be the answer choice B
Since there is no phase change, we can use the heat equation,
Q = mcΔT
where Q is the amount of energy transferred (J), m is the mass of the substance (kg), c is the specific heat (J kg⁻¹ °C⁻¹) and ΔT is the temperature difference (°C).
Q = 2000 J
m = 100 g = 0.1 kg
c = ?
ΔT = (70 °C - 50 °C) = 20 °C
By applying the formula,
2000 J = 0.1 kg x c x 20 °C
c = 2000 J / (0.1 kg x 20 °C)
c = 1000 J kg⁻¹ °C⁻¹
Hence, the specific heat capacity of the liquid is 1000 J kg⁻¹ °C⁻¹.
