What will the change in temperature be when 90 J are applied to 15 g of gold. (cgold = 0.126 J/g°C)

47.6°C is the change of temperature

Explanation:

To solve this question we must use the equation of specific heat of a material:

Q = m*ΔT*S

Where Q is heat applied = 90J

m is the mass of the substance = 15g gold

ΔT is change in temperature = Our incognite

S is specific heat of the material = 0.126J/g°C for gold

Replacing:

90J = 15g*ΔT*0.126J/g°C

90J/15g*0.126J/g°C = ΔT

ΔT = 47.6°C is the change of temperature

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.