Calculate the energy required to heat of 1.50 kg iron from -7.8 c to 15.0 c . assume the specific heat capacity of silver under these conditions is .0235 j*g^-1*k^-1 . be sure your answer has the correct number of significant digits.

There is 15.4 kJ of energy required to heat 1.50 kg iron.

Explanation:

Step 1: Data given

Mass of iron = 1.50 kg = 1500 grams

Initial temperature iron = -7.8 °C

Final temperature iron = 15.0 °C

Specific heat capacity of iron = 0.450 J/g*K = 0.450 J/g°C

Note: when heating iron from -7.8 °C to 15.0 °C, the iron does not change to another phase.

Step 2: Calculate the energy required

q = m*c*ΔT

⇒ with Q = the heat transfer ( in Joules)

⇒ with m= the mass of iron = 1.5 kg = 1500 grams

⇒ with c= the specific heat capacity of ir = 0.450 J/g°C

⇒ with ΔT = The change in temperature = T2 - T1 = 15.0 + 7.8 = 22.8 °C

q = 1500 * 22.8 * 0.450

q = 15390 J = 15.4 kJ

This is an endothermic reaction. There is 15.4 kJ of energy required to heat 1.50 kg iron.

since electrons are negative the answer is neagtaive

a is the correct answer