Relative Mass Worksheet
Explore the concepts of relative atomic mass, relative molecular mass, and isotopic abundance in this Grade 10 chemistry worksheet.
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Relative Mass Worksheet
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Read each question carefully and answer to the best of your ability. Show all your work for calculation questions.
1. The standard for relative atomic mass is the carbon-12 isotope, which is assigned a mass of exactly atomic mass units (amu).
2. The relative atomic mass of an element takes into account the and of its isotopes.
3. Relative molecular mass is the sum of the relative atomic masses of all atoms in a .
1. Which of the following best defines relative atomic mass?
The actual mass of an atom in grams.
The mass of an atom relative to 1/12th the mass of a carbon-12 atom.
The number of protons and neutrons in an atom.
The mass of an atom compared to a hydrogen atom.
2. An element has two isotopes: Isotope A with a mass of 10.0 amu and an abundance of 20%, and Isotope B with a mass of 11.0 amu and an abundance of 80%. What is the relative atomic mass of this element?
10.2 amu
10.8 amu
10.5 amu
11.0 amu
1. Explain why the relative atomic mass of an element is rarely a whole number.
2. Calculate the relative molecular mass of sulfuric acid (H₂SO₄), given the relative atomic masses: H=1.0, S=32.1, O=16.0.
1. All atoms of the same element have the same relative atomic mass.
True
False
2. The atomic mass unit (amu) is precisely defined as the mass of one proton.
True
False
Boron has two naturally occurring isotopes: boron-10 (mass = 10.013 amu) and boron-11 (mass = 11.009 amu). If the average atomic mass of boron is 10.81 amu, calculate the percentage abundance of each isotope.