Understanding Molar Heat of Combustion

What is the primary purpose of understanding the molar heat of combustion?

• To compare the energy output of different fuels

• To calculate the density of fuels

• To determine the color of the flame during combustion

• To measure the speed of combustion reactions

Why are combustion reactions considered exothermic?

• They absorb energy from the surroundings

• They occur at low temperatures

• They have a positive enthalpy change

• They release energy to the surroundings

In a calorimetry experiment, why is it important to ensure the thermometer does not touch the bottom of the can?

• To keep the thermometer clean

• To ensure the water boils evenly

• To avoid measuring the temperature of the can instead of the water

• To prevent the thermometer from breaking

What does the 'C' represent in the formula Q = MCΔT?

• The specific heat capacity of water

• The energy released

• The mass of the fuel

• The change in temperature

How is the energy absorbed by water calculated in a calorimetry experiment?

• By observing the color change in water

• By using the formula Q = MCΔT

• By measuring the volume of water

• By timing the duration of combustion

What is the first step in calculating the molar heat of combustion for butane?

• Determining the mass of water

• Converting joules to kilojoules

• Measuring the initial and final temperature of water

• Calculating the number of moles of butane

In the sample calculation, what is the final unit for expressing the molar heat of combustion per mole?

• Watts per mole

• Calories per mole

• Kilojoules per mole

• Joules per gram

Why is it necessary to convert joules to kilojoules in the sample calculation?

• To simplify the calculation

• To match the standard unit for energy

• To reduce the number of decimal places

• To make the numbers smaller

What is the significance of calculating the molar heat of combustion per gram?

• It calculates the density of the fuel

• It measures the speed of combustion

• It allows comparison of energy output based on mass

• It helps in determining the color of the flame

What is the specific heat capacity of water used in the calculations?

• 3.14 J/g°C

• 1.00 J/g°C

• 2.09 J/g°C

• 4.18 J/g°C