Chapter 1, Problem 1.12E

Is there a difference between a homogeneous mixture of hydrogen and oxygen in a 2:1 ratio and a sample of water vapor? Explain.

Describe any visual differences between the hydrated sample and the dried, anhydrous form. How would the following errors affect the empirical formula for the compound?  a. The student ran out of time and did not do the second heating. Explain how this error will affect the calculation for the number of moles of water in the hydrate? Will the final answer be artificially high or low? How do you know? b. The student recorded the mass of the cup + sample incorrectly and started with 2.2 g of hydrated compound but used 2.0 g in the calculations. Explain how this error will affect the calculation for the number of moles of water in the hydrate? Will the final answer be artificially high or low? How do you know?

Pure hydrogen gas H2 Match the description below with the following microscopic pictures. More than one picture may fit the description.

Part A) What principle states that the volumes of gases that combine in a chemical reaction are in the ratio of small whole numbers? A) Avogadro’s theory B) Law of constant conditions C) Law of conservation of volume D)Law of conservation of mass E) Law of combining volume Part B) Which of the following is not in the same ratio as the coefficients in a balanced chemical equation? A) Volumes of gaseous reactants and products B) Moles of reactants and products C) Molecules of reactants and products D) Masses of reactants and products E) None of the above Part C) What happens to the pressure of a gas if the number of molecules increases twofold (volume and temperature remains constant) A) The pressure decreases twofold B) The pressure remains constant C) The pressure decreases fourfold D) The pressure increases fourfold E) The pressure increases twofold

The great French chemist Antoine Lavoisier discovered the Law of Conservation of Mass in part by doing a famous experiment in 1775. In this experiment Lavoisier found that mercury(II) oxide, when heated, decomposed into liquid mercury and an invisible and previously unknown substance: oxygen gas.   Write a balanced chemical equation, including physical state symbols, for the decomposition of solid mercury(II) oxide (HgO) into liquid mercury and gaseous dioxygen. Suppose 48.0mL of dioxygen gas are produced by this reaction, at a temperature of 100.0°C and pressure of exactly 1atm. Calculate the mass of mercury(II) oxide that must have reacted. Be sure your answer has the correct number of significant digits.

How do I solve this: 282.5g / 1mol (1 molecule / 1.189 x 10-21)= The "/" are supposed to be fraction strokes.  It's supposed to be an Avogadro's number estimate. Where the mass of one oleic acid molecule (1.189 x 10-21) is used to determine the number of oleic acid molecules required to give a mass of 282.5g

A sample contains FeS2. At the end of its gravimetric determination, BaSO4 is weighed and the percentage of Fe is being searched for. What is an expression for the gravimetric factor in this determination? (The formulas represent the formula weights)       a) FeS2 / BaSO4   b) Fe /2 BaSO4   c) 2 Fe / BaSO4   d) FeS2 / 2 BaSO4   e) 2 FeS2 / BaSO4

1) When the sample is first put into the crucible and heated, the directions say to heat gently for the first five minutes. why do you suppose this is important?     2) Suppose that some of the compounds spilled out of the crucible after it was heated. Would that cause the percent by mass of water in the compound determined by the experiment to be too low, too high, or unchanged? Briefly explain your answer.     3) The unknown compounds used in this experiment are the following compounds. Based on your experimental results, what is the identity of the unknown compound you used? Show all calculations needed. Compound: CaSO4. 2H2O, MgSO4.7H2O, BaCl2.2H2O, ZnSO4.7H2O

Aspirin or acetyl salicylic acid is synthesized by reacting salicylic acid with acetic anhydride: C7H6O3 (salicylic acid) + C4H6O3 (acetic anhydride) = C9H8O4 (aspirin) + C2H4O2 (acetic acid) (a) How much salicylic acid is required to produce 0.400 g of aspirin (about the content in a tablet), assuming the acetic anhydride is present in excess? (b) Calculate the amount of salicylic acid needed if 74.9% of salicylic acid is converted to aspirin. (c) In one experiment, 9.26 g of salicylic acid is reacted with 8.54 g of acetic anhydride. Calculate the theoretical yield of aspirin and the percent yield if only 10.9 g of aspirin is produced.