Some Basic Concepts of Chemistry — MCQ Practice

What is the mass of $0.5\,\text{mol}$ of nitrogen gas (N$_2$)? (Atomic mass of N = $14\,\text{u}$)

Which of the following has the maximum number of molecules?

A compound contains $4.07\%$ hydrogen, $24.27\%$ carbon, and $71.65\%$ chlorine. Its molar mass is $98.96\,\text{g/mol}$. What are its empirical and molecular formulas? (Atomic masses: H=1, C=12, Cl=35.5)

What is the molarity of a solution prepared by dissolving $49\,\text{g}$ of H$_2$SO$_4$ in $250\,\text{mL}$ of water? (Assume the volume of the solution remains $250\,\text{mL}$ after dissolution. Atomic masses: H=1, S=32, O=16)

How many significant figures are present in $0.002040\,\text{g}$?

When $10\,\text{g}$ of CaCO$_3$ is decomposed, $4.4\,\text{g}$ of CO$_2$ is produced. The mass of CaO produced is: (Atomic masses: Ca=40, C=12, O=16)

A solution is prepared by mixing $100\,\text{mL}$ of $0.2\,\text{M}$ HCl with $150\,\text{mL}$ of $0.1\,\text{M}$ HCl. What is the final molarity of the mixed solution?