Question

calculate the final temperature of the water.

15. A 25.0g sample of aluminum, taken from boiling water is placed into 85.00 g of water at 23.5 °C. Calculate the final temperature of the water. 16. A 12.00 g sample of iron is taken from a beaker of water, at 98.6 °C, and placed into a 25.00 g sample of water at 19.4 °C. Calculate the final temperature of the water. 17 Con the boot of funion for wtar at the ton of the page convert it teatab Ilole anderal/mole

Answer 1

Essentially this is a heat balance problem.

Q = m x C_s x ΔT

m = mass; C_s = specific heat: ΔT = temp. difference; Q = Heat absorbed or Released.

1 cal = 4.184 J

Al ==> 0.215 cal = 0.89956 J/g.⁰C;

iron ==> 0.108 cal = 0.451872 J/g.⁰C

------------------------------------------------------------------------------------------------------------

15)

boiling water temperature = 100 ⁰C

let A = water & B = metal

heat gained by 85.0 g A = heat lost by 25.0 g B

m_A x C_A x (T_final - T_initial) = m_B x C_B x (T_initial - T_final)

85 g x 4.184 J/g.⁰C x (T_final - 23.5 ⁰C) = 25 g x 0.89956 J/g.⁰C x (100.0 ⁰C - T_final)

Let t be the final temp of water mixture.

85 g x 4.184 x ( t - 23.5 ) C = 25 g x 0.89956 x ( 100 - t) C

355.64 t - 8357.54 = 2248.9 - 22.489t

Therefore t = 10606.44 / 378.129 = 28.05 ⁰C

Answer : Final temp = 28.0 ⁰C

------------------------------------------------------------------------------------------------------------

16)

let A = water & B = metal

heat gained by 25.0 g A = heat lost by 12.0 g B

m_A x C_A x (T_final - T_initial) = m_B x C_B x (T_initial - T_final)

25 g x 4.184 J/g.⁰C x (T_final - 19.4 ⁰C) = 12 g x 0.451872 J/g.⁰C x (98.6 ⁰C - T_final)

Let t be the final temp of water mixture.

25 g x 4.184 x ( t - 19.4 ) C = 12 g x 0.89956 x ( 98.6 - t) C

104.6 t - 2029.24 = 1064.359392 - 10.79472 t

Therefore t = 3093.599392 / 115.39472 = 26.81 ⁰C

Answer : Final temp = 26.8 ⁰C

------------------------------------------------------------------------------------------------------------

Hope this helped you!

Thank You So Much! Please Rate this answer as you wish.("Thumbs Up")