To calculate the amount of heat needed to boil the given mass of octane (C₈H₁₈), we can use the formula:

$q = m \cdot C \cdot \Delta T$

Where:

• $q$ is the heat energy (in joules),
• $m$ is the mass of octane (in grams),
• $C$ is the specific heat capacity of octane (in J/g°C),
• $\Delta T$ is the change in temperature (in °C).

From the image, the following information is provided:

• Mass of octane ($m$): 65.7 g,
• Initial temperature ($T_i$): -35.9°C,
• Final temperature ($T_f$): The boiling point of octane is 125.6°C.

Now, let's use the specific heat capacity of octane, which is $C = 2.22 \, \text{J/g°C}$, and calculate the change in temperature:

$\Delta T = T_f - T_i = 125.6°C - (-35.9°C) = 161.5°C$

Now substitute all known values into the formula:

$q = 65.7 \, \text{g} \times 2.22 \, \text{J/g°C} \times 161.5°C$

Let me calculate the result. Given values mass = 65.7 # in grams specific_heat_capacity = 2.22 # in J/g°C delta_T = 125.6 - (-35.9) # temperature change in °C

Calculate the heat energy required

q = mass * specific_heat_capacity * delta_T qThe amount of heat required to boil 65.7 g of octane, starting from a temperature of -35.9°C, is approximately 23,555.42 joules (J).

Would you like further clarification or more details? Here are some related questions you might find helpful:

1. What is the significance of specific heat capacity in this calculation?
2. How would the result change if we used a different substance instead of octane?
3. What is the boiling point of octane, and why is it important in this context?
4. How would the calculation change if the phase transition from liquid to gas (vaporization) were included?
5. How can we convert the energy from joules to kilojoules?

Tip: When performing calculations involving heat, remember to check whether you need to account for phase changes (melting, boiling, etc.), as they may require additional heat calculations!