Multiple Choice
Given that the empirical formula is HO and the molar mass is 34.02 g/mol, what is the molecular formula of the compound?
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3. Chemical Reactions
Molecular Formula
Multiple Choice
A compound has an empirical formula of CH\(_2\) and a molar mass of 30.069 g/mol. What is its molecular formula?
A
C\(_2\)H\(_4\)
B
C\(_2\)H\(_6\)
C
CH\(_4\)
D
C\(_3\)H\(_6\)
Verified step by step guidance1
Calculate the molar mass of the empirical formula CH\(_2\). Use atomic masses: C = 12.01 g/mol, H = 1.008 g/mol. The empirical formula mass is \(12.01 + 2 \times 1.008\) g/mol.
Divide the given molar mass of the compound (30.069 g/mol) by the empirical formula mass calculated in step 1 to find the multiplier \(n\): \(n = \frac{30.069}{\text{empirical formula mass}}\).
Determine the molecular formula by multiplying each subscript in the empirical formula by the integer \(n\) found in step 2. For example, if \(n = 3\), multiply C by 3 and H by 3 \(\times\) 2 = 6.
Write the molecular formula using the new subscripts obtained in step 3. This will give the actual number of atoms of each element in the molecule.
Verify that the molecular formula mass matches the given molar mass by recalculating the molar mass using the molecular formula to ensure consistency.
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