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**The problem:**

On a hot summer day, you decide to make some iced tea. First, you brew 1.50 L of hot tea and leave it to steep until it has reached a temperature of T_tea = 75.0 C. You then add 0.975 kg of ice taken from the freezer at a temperature of T_ice = 0 C. By the time the mix reaches equilibrium, all of the ice has melted. What is the final temperature T_f of the mixture?

For the purposes of this problem, assume that the tea has the same thermodynamic properties as plain water.

The specific heat of water is = 4190.

The heat of fusion of ice is = 3.33×105 .

The density of the tea is = 1.00 .

**My attempt:**

I wrote the following expression to find T_f:

T_f = (m_tea*c*T_tea + m_ice*c*T_ice - L_f*m_ice) / (cm_tea + cm_ice)

I'm pretty sure this is right, but when I plug in the variables, I get:

(1.5*4190*75 - .975*3.33e5) / (4190*1.5 + .975*2050) = 17.71 C

17 degrees seems like a reasonable answer but it's not right. What could I be doing wrong?

Thanks.