WAEC WASSCE Thermochemistry — practice questions
50 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice WAEC WASSCE Thermochemistry in the app →How is energy defined?What is potential energy?What is kinetic energy?What does the law of conservation of energy state about a chemical or physical change?What is thermal energy?Two bodies at different temperatures are placed in contact. What happens?A cold pack feels cold when the salt inside dissolves in water. How is this process classified?How many joules is one calorie defined to equal?How does the nutritional Calorie written with a capital C relate to the ordinary calorie?Why is heat capacity an extensive property while specific heat capacity is intensive?A large and a small cast iron pan are compared. Which quantity is the same for both?A flask holding 8.0 x 10^2 g of water is heated from 21 degrees C to 85 degrees C. How much heat does the wateA 348 g metal piece absorbs 6.64 kJ and warms from 22.4 degrees C to 43.6 degrees C. What is its specific heatA 217 g metal absorbs 1.43 kJ and warms from 24.5 degrees C to 39.1 degrees C. What is its specific heat and lWhat is calorimetry used to measure?In a calorimetric measurement, what is meant by the system?Why do polystyrene coffee cup calorimeters give less accurate results than research calorimeters?Hot metal is dropped into cool water in an ideal calorimeter. Which relation holds between the two heat valuesA 360.0 g steel rebar (0.449 J/g degree C) is dropped into 425 mL of water at 24.0 degrees C, giving a final 4A 59.7 g metal from boiling water at 100.0 degrees C is put into 60.0 g of water at 22.0 degrees C, reaching 2Mixing 50.0 mL of 1.00 M HCl with 50.0 mL of 1.00 M NaOH at 22.0 degrees C raises the temperature to 28.9 degrDissolving 3.21 g of NH4NO3 in 50.0 g of water cools it from 24.9 degrees C to 20.3 degrees C. What is the sigWhat distinguishes a bomb calorimeter from a coffee cup calorimeter?Burning 0.963 g of benzene raises a bomb calorimeter by 8.39 degrees C. With a bomb capacity of 784 J/degree CA serving holds 5 g protein, 31 g carbohydrate and 12 g fat. Using 4, 4 and 9 Calories per gram, what is its eWhat is the internal energy of a substance?In the first law expression relating internal energy change to heat and work, when is the work term positive?What makes a quantity a state function?How is enthalpy defined?Why is the heat measured in a bomb calorimeter not equal to the enthalpy change of the reaction?Given that H2(g) + half O2(g) giving H2O(l) has an enthalpy change of -286 kJ, what is it for 2H2(g) + O2(g) gForming 1 mol of liquid water from its elements releases 286 kJ, but forming gaseous water releases only 242 kWhat happens to the enthalpy change when the direction of a thermochemical equation is reversed?Reacting 0.0500 mol of HCl with 0.0500 mol of NaOH produces 2.9 kJ of heat. What is the enthalpy change per moA gummy bear with 2.67 g sucrose (342.3 g/mol) reacts with 7.19 g KClO3 (122.5 g/mol) as C12H22O11 + 8KClO3. WIn that gummy bear reaction, 43.7 kJ is produced from 0.0587 mol of the limiting KClO3. What is the enthalpy cWhat is the standard enthalpy of combustion of a substance?How much heat is produced by burning 4.00 mol of acetylene, whose enthalpy of combustion is -1301.1 kJ/mol?Burning 1.00 L of isooctane (density 0.692 g/mL, 114 g/mol, -5460 kJ/mol) produces how much heat?What is a standard enthalpy of formation?What is the standard enthalpy of formation of an element in its most stable form?Given that 3O2(g) giving 2O3(g) has a standard enthalpy change of +286 kJ, what is the enthalpy of formation oWhat does Hess's law state?Carbon burns to CO with an enthalpy change of -111 kJ, and CO burns to CO2 with -283 kJ. What is the value forGiven Fe + Cl2 giving FeCl2 at -341.8 kJ, and FeCl2 + half Cl2 giving FeCl3 at -57.7 kJ, what is the formationGiven N2 + O2 giving 2NO at +180.5 kJ and NO + half O2 giving NO2 at -57.06 kJ, what is the value for N2 + 2O2In a Hess's law problem a given step is reversed and then halved. What happens to its enthalpy change?How is a standard reaction enthalpy calculated from standard enthalpies of formation?Using formation values of -207.4 for HNO3(aq), +90.2 for NO(g), +33.2 for NO2(g) and -285.8 kJ/mol for H2O(l),Using formation values of -278 for C2H5OH(l), -286 for H2O(l) and -394 kJ/mol for CO2(g), what is the heat of