What difference is necessary for heat to flow between two systems? Can you think of an exception to your answer?

Two 20.0 g ice cubes at −15.0 ∘C−15.0⁢ ∘C are placed into 285 g285 g of water at 25.0 ∘C.25.0⁢ ∘C. Assuming no energy is transferred to or from the surroundings, calculate the final temperature, ?f,Tf, of the water after all the ice melts.

Every day a certain amount of water evaporates from Earth’s oceans, lakes, and land surface and forms water vapor and clouds in the atmosphere. Every day a certain amount of rain falls back to Earth. Make the reasonable assumption that, on average, the energy absorbed by the evaporation and lifting of the water is equal to the energy released by its condensation and falling back to earth. The evaporation of one mole of water requires approximately 40.6×103 J of heat. An equal amount of heat is released when a mole of water condenses. The annual volume of rainfall on Earth is approximately 4.9×105 km3 and the average cloud altitude is 8.9 km above Earth’s surface. How much energy, in joules, is required every day to evaporate and lift the water?

If the following three thermochemical equations are added together, what is the resulting equation:2 XO2 (g) +2 CO (g) →→ 2 XO (g) + 2 CO2 (g)2 XO (g) + 2/3 CO2(g) →→ 2/3 X3O4 (s) + 2/3 CO (g)2/3 X3O4 (s) + 1/3 CO2 (g) →→ X2O3 (g) + 1/3 CO (g)     Question 17 options:   6 XO (g) + 2 CO2(g) →→ 2 X3O4 (s) + 2 CO (g)   2 XO2 (s) + CO (g) →→ X2O3 (s) + CO2 (g)   C (s) + 3 XO2 (g) →→ X3O4 (g) + CO2 (g)   2 X3O4 (s) + CO2 (g)  →→ 3 X2O3 (g) + CO (g)   CO (g) + XO2 (g) →→ XO (g) + CO2 (g)

An electrical heater is used to supply 105.0 J of energy to a 15.0 g sample of aluminum (specific heat is 0.901 J/(goC), originally at 295.0 Kelvin. Determine the final temperature in Kelvin.

Suppose you place equal amounts of 60.0°C and 20.0°C water next to each other in an insulated box with the two samples separated by a thin piece of metal. Assuming no heat is lost to the surroundings, what is the final temperature of the two samples of water?

Consider the problem of hammering a nail into a board.  With due reqard for the hand holding the nail, place its pointed tip on the wood and strike it  with a hammer.  If the wood is hard so  the nail does not go in easily, you will notice that the nail gets warm, especially after several strikes.    We can figure out how much its temperature will rise by connecting what we know about Newtonian mechanics with what we are learning about temperature and heat. Let the nail have a mass of 50 g and strike it with one strong hammer blow.  The hammer head has a mass of 0.5 kg (that's about 1 lb, so this is a good sized carpenter's hammer).  Assume the impact velocity of the hammer on the head is 13 m/s and that it stops firmly at each blow. To make a reasonable assumption about the outcome, also assume that 75% of the energy of the hammer is converted into heat after the blow.   The specific heat of the steel in the nail is about 482 J kg-1 K-1  . What is the temperature increase in the nail…

A 102.8 g sample of a metal initially at 183.00C is placed in 35.0 ml of water initially at 25.0 0C. After reaching thermal equilibrium, the final temperature of the system is 58.80C. What is the identity of the metal? Assume no heat is lost to the surroundings.