HEAT CALCULATIONS

Solid aluminum has a specific heat capacity of 0.90 J/g*K. How many joules of heat are absorbed to raise the temperature of 24.0 grams of aluminum from 300. K to 350. K?

• 22 J

• 45 J

• 1080 J

• 1200 J

What is the amount of heat required to melt 43 grams of solid magnesium oxide at its melting point? The heat of fusion is 1.9 × 10³ J/g.

• 2.33 × 10² J

• 4.40 × 10¹ J

• 8.17 × 10⁴ J

• 3.42× 10⁵ J

What is the amount of heat released by 1.00 gram of liquid water at 0°C when it changes to 1.00 gram of ice at 0°C?

• 4.18 J

• 273 J

• 334 J

• 2260 J

Which phase change results in an increase in entropy?

• I₂(g) → I₂(s)

• CH₄(g) → CH₄(l)

• Br₂(l) → Br₂(g)

• H₂O(l) → H₂O(s)

What is the amount of heat absorbed when the temperature of 75 grams of water increases from 20°C to 35°C?

• 1100 J

• 4700 J

• 6300 J

• 11 000 J

Which numerical setup can be used to calculate the heat energy required to completely melt 100. grams of H₂O(s) at 0°C?

• (100. g)(334 J/g)

• (100. g)(2260 J/g)

• (100. g)(4.18 J/g·K)(0°C)

• (100. g)(4.18 J/g·K)(273 K)

What is the amount of heat, in joules, required to increase the temperature of a 49.5-gram sample of water from 22°C to 66°C?

• 2.2 × 10³ J

• 4.6 × 10³ J

• 9.1 × 10³ J

• 1.4 × 10⁴ J

A cube of iron at 20.°C is placed in contact with a cube of copper at 60.°C. Which statement describes the initial flow of heat between the cubes?

• Heat flows from the copper cube to the iron cube.

• Heat flows from the iron cube to the copper cube.

• Heat flows in both directions between the cubes.

• Heat does not flow between the cubes.

As a 15.1-gram sample of a metal absorbs 48.75 J of heat, its temperature increases 25.0 K. What is the specific heat capacity of the metal?

• 0.129 J/g•K

• 1.95 J/g•K

• 3.23 J/g•K

• 7.74 J/g•K

How many joules of heat are absorbed to raise the temperature of 435 grams of water at 1 atm from 25°C to its boiling point, 100.°C?

• 4.5 × 10⁴ J

• 1.4 × 10⁵ J

• 2.5 × 10⁵ J

• 7.4 × 10⁷ J