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What is the relative formula mass of calcium hydroxide, Ca(OH)₂? Use the Periodic Table to help you - OCR Gateway - GCSE Chemistry: Combined Science - Question 3 - 2019 - Paper 3
Question 3
What is the relative formula mass of calcium hydroxide, Ca(OH)₂? Use the Periodic Table to help you. A 57.1 B 58.1 C 74.1 D 114.2 Your answer ________
Worked Solution & Example Answer:What is the relative formula mass of calcium hydroxide, Ca(OH)₂? Use the Periodic Table to help you - OCR Gateway - GCSE Chemistry: Combined Science - Question 3 - 2019 - Paper 3
Step 1
Calculate the relative formula mass of Ca(OH)₂
Answer
To find the relative formula mass of calcium hydroxide, we can break down the molecular composition:
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Identify the components: Calcium (Ca), Oxygen (O), and Hydrogen (H).
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Find the atomic masses from the Periodic Table:
- Calcium (Ca): approximately 40.1 g/mol
- Oxygen (O): approximately 16.0 g/mol (2 Oxygen atoms)
- Hydrogen (H): approximately 1.0 g/mol (2 Hydrogen atoms)
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Calculate the mass:
- For Ca: ( 1 \times 40.1 = 40.1 \ g/mol )
- For O: ( 2 \times 16.0 = 32.0 \ g/mol )
- For H: ( 2 \times 1.0 = 2.0 \ g/mol )
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Add the masses together:
Thus, the relative formula mass of calcium hydroxide, Ca(OH)₂, is 74.1 g/mol. Therefore, the correct answer is C.