Lesson: Chapter 7 — Quantification of Elements and Compounds

7.2. Relative molecular mass 4 of 10 Reset answers

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Question 4

What is the relative molecular mass of sulphuric acid (H₂SO₄)? (A_r: H = 1, O = 16, S = 32)

A 50 B 49 C 130 D 98

The right answer is the one marked above.

98. H₂SO₄ = (2 × 1) + 32 + (4 × 16) = 2 + 32 + 64 = 98.

49 comes from taking 1 + 32 + 16, ignoring both subscripts. The 64 from four oxygens is the largest part of the total, so it is the one to get right.

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