An ionic solid is dissolved in a beaker of water at room temperature. After the crystals have dissolved, the sides of the beaker feel cold. State the thermochemical term for the type of process involved, and identify the sign of the enthalpy change.

What is the change in internal energy for the system?

What is the change in enthalpy for the reaction: 2B (s) + 3H2(g) → B2H6 (g) given these thermochemical equations? B2H6 (g) + 302 (g) →B2O3 (s) + 3 H₂O (g) AH = -2032 kJ 2B (s) + 3/2 O2 (g) → B2O3 (s) AH = -1272 kJ H2(g) + 1/2 O2 (g) → H2O (g) AH -241.8 kJ -4029 kJ +518.2 kJ +34.6 kJ -3546 kJ

A piece of solid substance weights 4.0 g, and requires 150 J to increase its temperature from 30.0 degrees Celsius to 40.0 degrees Celsius. What is the specific heat capacity of the substance?

A 79.1 g sample of an unknown solid is heated to 62.6ºC and placed into a calorimeter containing 92.1 g of water at 22ºC. If the final temperature of the solid sample and the water is 32.5ºC, what is the specific heat of the solid? Please provide your final answer rounded to two decimal places.

A 44.0 g sample of unknown metal at 99.0°C was placed in a constant-pressure calorimeter containing 80.0 g of water at 24.0°C, the final temperature of the system was found to be 28.4°C. Calculate the specific heat of the metal.

Hot water heaters often use natural gas (methane) to generate heat. Methane and oxygen react to form carbon monoxide according to the overall equation: 2CH4(g)+3O2(g) = 2CO(g)+4H2O(g) The enthalpy of formation for each compound are as follows: CH4: - 74.6 O2: 0 CO: - 110.5 H2O: - 285.8 Part A: calculate the overall enthalpy change of the reaction. Part B: A typical water heater contains 40.0 gallons of water. After a long vacation, you come home and turn your water heater from "vacation mode" to hot. How many moles of methane must be combusted to heat the water in your water heater from 30.0°C to 48.0°C? The density of water is 3.79 kg/gal, the specific heat capacity of water is 4.182 J/g°C, and the water heater has a heat capacity of 850.0 J/g°C.

A 22.86 g sample of a substance is initially at 26.5 ∘C. After absorbing 574 cal of heat, the temperature of the substance is 194.6 ∘C. What is the specific heat (??)(S⁢H) of the substance?

A group of students place 15.41g of a metal into a test tube. They place the test tube into a beaker of boiling water until the temperature of the metal was 89.8°C. Then they quickly place the heated metal into a beaker of 10.47g of water with an initial temperature of 16.4°C. The temperature of the mixturecame to rest at 26.1°C. What is the specific heat of the metal used? (CH2O = 4.18 J/g°C)