Multiple Choice
What is the percent by mass of magnesium sulfate (MgSO_4) in magnesium sulfate heptahydrate (MgSO_4 · 7H_2O)?
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3. Chemical Reactions
Mass Percent
Multiple Choice
What is the percent by mass of sodium in NaCl? Choose the closest value.
A
22.58%
B
32.37%
C
45.98%
D
16.18%
Verified step by step guidance1
Identify the chemical formula of the compound, which is NaCl, consisting of sodium (Na) and chlorine (Cl).
Find the atomic masses of sodium and chlorine from the periodic table: sodium (Na) has an atomic mass of approximately 22.99 g/mol, and chlorine (Cl) has an atomic mass of approximately 35.45 g/mol.
Calculate the molar mass of NaCl by adding the atomic masses of sodium and chlorine: \(\text{Molar mass of NaCl} = 22.99 + 35.45\) g/mol.
Determine the percent by mass of sodium in NaCl using the formula: \(\text{Percent by mass of Na} = \left( \frac{\text{Atomic mass of Na}}{\text{Molar mass of NaCl}} \right) \times 100\%\).
Substitute the values into the formula and simplify to find the percent by mass of sodium, then compare your result to the given options to choose the closest value.
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