Multiple Choice
How many moles of K_2SO_4 are present in 15.0 g of K_2SO_4? (Molar mass of K_2SO_4 = 174 g/mol)
37
views
2. Atoms & Elements
Mole Concept
Struggling with General Chemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which of the following samples contains the greatest number of moles of atoms?
A
18 g of H2O
B
24 g of C
C
32 g of O2
D
58.5 g of NaCl
Verified step by step guidance1
Identify the molar mass of each substance to convert the given mass into moles. Use the periodic table to find atomic masses: H = 1 g/mol, O = 16 g/mol, C = 12 g/mol, Na = 23 g/mol, Cl = 35.5 g/mol.
Calculate the molar mass of each compound: For H\_2O, molar mass = 2(1) + 16 = 18 g/mol; For C (elemental), molar mass = 12 g/mol; For O\_2, molar mass = 2(16) = 32 g/mol; For NaCl, molar mass = 23 + 35.5 = 58.5 g/mol.
Determine the number of moles of each sample by dividing the given mass by the molar mass: moles = mass / molar mass.
Calculate the total number of atoms in each sample. For elemental substances like C and O\_2, multiply moles by the number of atoms per molecule (1 for C, 2 for O\_2). For compounds like H\_2O and NaCl, multiply moles by the total number of atoms per formula unit (3 for H\_2O, 2 for NaCl).
Compare the total number of atoms calculated for each sample to determine which contains the greatest number of moles of atoms.
Related Videos
Related Practice
