Answer:
- <u>You need to convert the number of atoms of Ca into mass in grams, using Avogadro's number and the atomic mass of Ca.</u>
Explanation:
The amount of matter is measured in grams. Thus, you need to convert the number of atoms of Ca (calcium) into mass to compare with 2.45 grams of Mg.
To convert the atoms of calcium into mass, you divide by Avogadro's number, to obtain the number of moles of atoms, and then divide by the atomic mass of calcium.
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<u>1. Number of moles, n</u>

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<u>2. Mass</u>
- mass = number of moles × atomic mass
- mass = 0.053969mol × 40.078g/mol = 2.16g
Then, 2.45 g of Mg represent a greaer mass than the 3.25 × 10²² atoms of Ca.
Answer:
A voltaic cell that uses the oxidation of a fuel to produce electricity
Explanation:
A fuel cell is a voltaic cell that converts the chemical energy of a fuel and an oxidizing agent into electricity.
A. is wrong. This definition is so broad that it could include a candle in a cup.
C is wrong. The batteries in flashlights and cell phones are not fuel cells.
The answer is C. Elastic potential energy