x gram of water at 40 degrees celsius is mixed with 4 grams of water at 90 degrees celsius the final temperature of the water is 50

x gram of water at 40 degrees celsius is mixed with 4 grams of water a

1.	x gram of water at 40 degrees celsius is mixed with 4 grams of water at 90 degrees celsius the final temperature of the water is 50
Answer» since it is given that 50 gm water at 20 ⁰ C and 50 gm of water at 40⁰ C are mixed. Since the masses of the LIQUID at different temperatures are same, the answer is very easy and simple : average of 20⁰C and 40⁰C. that is: 30⁰C.Explanation: final temperature of the MIXTURE = = [ m1 * T1 + m2 * T2 ] / (m1 + m2) = [ 50 gm * 20⁰ C + 50 gm * 40⁰C ] / (50+50) = 3,000 / 100 = 30⁰C another way using specific heats : let the final temperature be = T ⁰C Amount of heat given out by the hot water = m * s * (40⁰C - T) = 50 gm * s* (40 -T) Amount of heat taken in by the COLD water = m * s * (T - 20⁰C) = 50 gm * s * (T - 20 ) As the amounts are equal, because the heat is transferred from hot water to the cold water without any loss of heat to any surroundings, 50 * s * (40 -T) = 50 gm * s * (T-20) 40 - T = T - 20 2 T = 60 => T = 30⁰C