Chemistry Questions
- What is the mole ratio of PbO2 to water in the chemical reaction of a car battery: Pb + PbO2 + 2H2SO4 ‚Üí 2PbSO4 + 2H2O?
- A chemist is using a solution of HNO3 that has a pH of 3.75. What is the concentration of hydroxide ions [OH⁻] in the solution, and what is the pOH of the solution?
- Which diagram correctly shows the distribution of electrons in the electron shells of a helium atom, given that its electron configuration is 1s²?
- What is Avogadro’s number? a. the number of atoms in exactly 14.00 g of carbon-12 b. the number of atoms in a kilogram of any substance c. the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance d. the number of atoms, molecules, ions, formula units, or other particles in a gram of a substance
- How are refraction and diffraction similar, and how are they different? Check all that apply: 1. Refraction and diffraction both involve the bending of waves. 2. Refraction and diffraction both involve the bending of waves through a medium. 3. Refraction and diffraction both involve the bending of waves around objects. 4. Refraction involves the bending of waves through a medium, while diffraction involves the bending of waves around an object. 5. Refraction involves the bending of waves around an object, while diffraction involves the bending of waves through a medium.
- What is the solution to the following problem, expressed to the correct number of significant figures: (102,900 √∑ 12) + (170 + 1.27) = ?
- Which of the following statements about gases is true? A. A gas is not easily compressed due to low intermolecular forces. B. A gas does not easily mix with other gases because of the high density of gaseous substances. C. Gas particles have strong intermolecular forces, allowing them to flow easily. D. Gas particles spread out to fill a container, resulting in a low density of the gas.
- A solution with a pH of 13 has approximately how many moles of OH⁻ ions per liter? How many moles of H⁺ would this same solution have per liter? (Provide your answer in decimal form.) Additionally, a different solution with an H⁺ concentration of 1.0 × 10⁻⁴ would have a pH of __________.
- How do real gases differ from ideal gases? A. In a real gas, the particles are not always in motion. B. The particles do not bounce off walls. C. The particles occupy volume. D. Intermolecular forces exist between particles. E. The average energy depends only on temperature. F. The particles do not lose energy from collisions.
- Can you match the molecular shapes to the correct Lewis structures? (Options are provided in the image below.)
- The following reaction occurs in a car’s catalytic converter: 2NO(g) + 2CO(g) ==> N2(g) + 2CO2(g). Which answer best describes the reducing and oxidizing processes in this reaction? 1) NO and CO are both reducing agents. 2) NO and CO are both oxidizing agents. 3) The oxidation state of nitrogen in NO changes from +2 to 0, and the oxidation state of carbon in CO changes from +2 to +4 as the reaction proceeds. 4) The oxidation state of nitrogen in NO changes from 0 to +2, and the oxidation state of carbon in CO changes from +4 to +2 as the reaction proceeds.
- Identify each example in the diagram as a carbon source or a carbon sink.