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Questions in chemistry

📝 Answered - Which of the following sequences lists the relative sizes of particles in a water mixture from smallest to largest? A. Solutions, suspensions, colloids B. Solutions, colloids, suspensions C. Colloids, solutions, suspensions D. Colloids, suspensions, solutions E. Suspensions, colloids, solutions

📝 Answered - Which one of the following elements does not exist as a diatomic molecule in nature? A. Hydrogen B. Nitrogen C. Fluorine D. Neon

📝 Answered - An archaeologist discovered some charcoal at an excavation site. He sent the samples to a lab for C-14 dating, knowing that the half-life of C-14 is approximately 5,600 years. The lab reported that the charcoal had 1/8 the amount of C-14 in it that a living sample would have. How many years old was the charcoal? A. 700 years B. 1,867 years C. 8,400 years D. 16,800 years E. 44,800 years

📝 Answered - The half-life of thorium-227 is 18.72 days. How many days are required for three-fourths of a given amount to decay?

📝 Answered - 1 mol of hydrogen gas and 1 mol of iodine vapor were mixed and allowed to react. After t seconds, 0.8 mol of hydrogen remained. The number of moles of hydrogen iodide formed at t seconds was: A) 0.2 B) 0.4 C) 0.8 D) 1.6 The answer is B. Please explain how you worked this out.

📝 Answered - How many atoms are in 3.50 moles of calcium (Ca)?

📝 Answered - What is the geometry of the HBr molecule? What is the geometry of the SF₂ molecule?

📝 Answered - Unknown element X combines with oxygen to form the compound [tex]XO_2[/tex]. If 44.0 grams of element X combines with 8.00 grams of oxygen, what is the atomic mass of element X? A. 16 amu B. 44 amu C. 88 amu D. 176 amu E. 352 amu

📝 Answered - How does the environment influence natural selection?

📝 Answered - Which of the gases listed below would not be collected via water displacement? A. CO₂ B. CH₄ C. O₂ D. NH₃ E. H₂