Question

Q=mcAt

Answer 1

Answer:

1.51 × 10⁶ kJ

General Formulas and Concepts:

Stoichiometry

• Using Dimensional Analysis

Thermochemistry

Specific Heat Formula: q = mcΔT

• q is heat (in J)
• m is mass (in g)
• c is specific heat formula (in J/g °C)
• ΔT is change in temperature (in °C)

Explanation:

Step 1: Define

[Given] m = 114.32 g

[Given] c = 4186 J/kg °C

[Given] ΔT = 18.0 °C - 14.85 °C = 3.15 °C

[Solve] q

Step 2: Convert Pt. 1

1 kg = 1000 g

$\displaystyle 4186 \ J/kg \ ^\circ C(\frac{1000 \ g}{1 \ kg}) = 4186000 \ J/g \ ^\circ C$

Step 3: Solve

1. Substitute in variables [Specific Heat Formula]:                                            q = (114.32 g)(418600 J/g °C)(3.15 °C)
2. Multiply:                                                                                                             q = (4.78544 × 10⁸ J/°C)(3.15 °C)
3. Multiply:                                                                                                             q = 1.50741 × 10⁹ J

Step 4: Convert Pt. 2

1000 J = 1 kJ

$\displaystyle 1.50741 \cdot 10^9 \ J(\frac{1 \ kJ}{1000 \ J}) = 1.50741 \cdot 10^6 \ kJ$

Step 5: Check

Follow sig fig rules and round. We are given 3 sig figs as our lowest.

1.50741 × 10⁶ kJ ≈ 1.51 × 10⁶ kJ