specific heat

[jennypear]

The specific heat of a 109-g block of material is to be determined. The block is placed in a 34.0-g copper calorimeter that also holds 52.0 g of water. The system is initially at 20.0°C. Then 140 g of water at 83.0°C are added to the calorimeter vessel. When thermal equilibrium is attained, the temperature of the water is 51.0°C. What is the specific heat of the block?

cu specific heat=.386J/gdegree
water sh=4.18j/gdegree

34g(.386J/gdegree)(31degree) + 52g(4.18J/gdegree)(31degree) +
109g(unknown sh)31degree = 140g(4.18J/gdegree)32degree

406.844J + 6738.16J + 3379g*degree(unknown sh) = 18726.4J
3379g*degree(unknown sh) + 7145.004J = 18726.4J
3379g*degree(unknown sh) = 11581.396J
unknown sh = 3.42 J/gdegree

this isnt the correct answer
thanks for your time

[Andrew Mason]

The specific heat of a 109-g block of material is to be determined. The block is placed in a 34.0-g copper calorimeter that also holds 52.0 g of water. The system is initially at 20.0°C. Then 140 g of water at 83.0°C are added to the calorimeter vessel. When thermal equilibrium is attained, the temperature of the water is 51.0°C. What is the specific heat of the block? It is always easier and clearer to work it out algebraically and then plug in numbers. But your work appears to be correct. What is the 'correct' answer?

AM