What is the total energy needed to boil 255 grams of water, given that the

Chemistry

1 answer:

nexus9112 [7]3 years ago

3 0

Answer:

<u>575,000 J</u>

Explanation:

<u>1) Convert the mass of water into number of moles</u>

Molar mass of water: 18.015 g/mol

Number of moles, n = mass in grams / molar mass

n = 255 g / 18.015 g/mol = 14.15 mol

<u>2) Use the formula E = n × ΔH vap</u>

This is, you have to multiply the molar ΔH vaporization by the number of moles to find the total energy to boil the given amount of water.

E = 14.15 mol × 40,650 J/mol = 575,395.5 J

<u>3) Round to the correct number of significant figures.</u>

The mass of water is the measurement with the least number of significant figures (3), so you must report the answer with 3 significant figures,

E = 575,000 J ← answer

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