Multiple Choice
What is the mass percentage of carbon (C) in caffeine, C₈H₁₀N₄O₂? Provide an answer to two decimal places.
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3. Chemical Reactions
Mass Percent
Multiple Choice
What is the mass percent of bromine in the compound NaBr?
A
Approximately 60.0%
B
Approximately 50.0%
C
Approximately 22.3%
D
Approximately 77.7%
Verified step by step guidance1
Identify the elements in the compound NaBr, which are sodium (Na) and bromine (Br).
Find the atomic masses of sodium and bromine from the periodic table. Sodium (Na) has an atomic mass of approximately 22.99 g/mol, and bromine (Br) has an atomic mass of approximately 79.90 g/mol.
Calculate the molar mass of NaBr by adding the atomic masses of sodium and bromine: \(M_{NaBr} = M_{Na} + M_{Br}\).
Calculate the mass percent of bromine in NaBr using the formula: \(\text{Mass \% of Br} = \left( \frac{M_{Br}}{M_{NaBr}} \right) \times 100\%\).
Substitute the atomic masses into the formula and simplify to find the mass percent of bromine in NaBr.
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