Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below. When 0.025 mol of Na is added to 100.00 g of water, the temperature of the resulting solution rises from 25.00°C to 35.75°C. If the reaction is exothermic, what is the sign of the enthalpy change (ΔH) for this reaction?

How much heat is released when one mole of steam (18.0 g) at 100.0 °C is converted to water at 25.0 °C?

If the aluminum block is initially at 25 °C, what is the final temperature of the block after the evaporation of the alcohol, assuming the heat required for the vaporization of the alcohol comes only from the aluminum block?

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l) with ΔH = -890.0 kJ. Calculate the value of q (kJ) in this exothermic reaction when 1.70 g of CH4 is burned.

Which of the following is an endothermic process?

Sodium reacts violently with water according to the equation: 2 Na(s) + 2 H2O(l) → 2 NaOH(aq) + H2(g). The resulting solution has a higher temperature than the water prior to the addition of sodium. What are the signs of ΔH° and ΔS° for this reaction?

Suppose that 0.79 g of water condenses on a 95.0-g block of copper that is initially at 23 °C. If the heat released during condensation goes only to warming the copper block, what is the final temperature (in °C) of the copper block? Assume a constant specific heat capacity for copper.

Suppose that 0.95 g of water condenses on a 75.0 g block of iron that is initially at 22°C. If the heat released during condensation is used only to warm the iron block, what is the final temperature (in °C) of the iron block? (Assume a constant enthalpy of vaporization for water of 2260 J/g and specific heat capacity of iron as 0.449 J/g°C.)

Suppose that 1.08 g of rubbing alcohol (C3H8O) evaporates from a 74.0 g aluminum block. If the aluminum block is initially at 25 °C, what is the final temperature of the block after the evaporation of the alcohol? Assume that the heat required for the evaporation is absorbed entirely from the aluminum block, and the heat of vaporization of rubbing alcohol is 45.4 kJ/mol. The specific heat capacity of aluminum is 0.897 J/g°C.