Question

When 40.0 mL of 1.00 M H2SO4 is added to 80.0 mL of 1.00 M NaOH at 20.00°C in a coffee cup calorimeter, the temperature of the aqueous solution increases to 29.20°C. If the mass of the solution is 120.0 g and the specific heat of the calorimeter and solution is 4.184 J/g • °C, how much heat is given off in the reaction? (Ignore the mass of the calorimeter in the calculation.) Use q=mCp(tiangle)t
4.62 kJ
10.0 kJ
14.7 kJ
38.5 kJ

Answer 1

Answer:

$\boxed{\text{4.62 kJ}}$

Explanation:

There are two heat transfers to consider:

$\begin{array}{ccccc}\text{Heat released by reaction} & + &\text{heat absorbed by water} & =& 0\\q_{1}& + & q_{2} & = & 0\\q_{1}& + & mC_{p}\Delta T & = & 0\\\end{array}$

Calculate q₂

 m = 120.0 g

 C = 4.184 J·°C⁻¹g⁻¹

 T₂ = 29.20 °C

 T₁ = 20.00 °C

ΔT = T₂ - T₁ =(29.20 – 20.00) °C =9.20 °C

 q₂ = 120.0 g × 4.184 J·°C⁻¹g⁻¹ × 9.20 °C = 4620 J = 4.62 kJ

Calculate q₁

q₁ + 4.62 kJ = 0

q₁ = -4.62 kJ

The negative sign shows that heat is given off.

$\text{The reaction gives off }\boxed{\textbf{4.62 kJ}}$

Answer 2

Answer:

A. 4.62kJ

Explanation: