Base your answers to questions 5 on the information below and on your knowledge of chemistry.

A hydrate is a compound that has water molecules within its crystal structure. Magnesium sulfate heptahydrate, MgSO₄•7H₂O, is a hydrated form of magnesium sulfate. The hydrated compound has 7 moles of H₂O for each mole of MgSO₄. When 5.06 grams of MgSO₄•7H₂O are heated to at least 300.°C in a crucible by using a laboratory burner, the water molecules are released. The sample was heated repeatedly, until the remaining MgSO₄ had a constant mass of 2.47 grams. During this laboratory activity, appropriate safety equipment was used and safety procedures were followed.

Base your answers to questions 6 on the information below and on your knowledge of chemistry.

The atomic mass and natural abundance of the naturally occuring isotopes of hydrogen are shown in the table below.

The isotope H-2, also called deuterium, is usually represented by the symbol “D.” Heavy water forms when deuterium reacts with oxygen, producing molecules of D₂O.

Base your answers to questions 7 on the information below and on your knowledge of chemistry.

The table below contains selected information about chlorine and two compounds containing chlorine. One piece of information is missing for each of the substances in the table.

Base your answers to questions 8 on the information below and on your knowledge of chemistry.

Fruit growers in Florida protect oranges when the temperature is near freezing by spraying water on them. It is the freezing of the water that protects the oranges from frost damage. When H₂O(ℓ) at 0°C changes to H₂O(s) at 0°C, heat energy is released. This energy helps to prevent the temperature inside the orange from dropping below freezing, which could damage the fruit. After harvesting, oranges can be exposed to ethene gas, C₂H₄, to improve their color.

Base your answers to questions 9 on the information below and on your knowledge of chemistry.

The unique odors and flavors of many fruits are primarily due to small quantities of a certain class of organic compounds. The equation below represents the production of one of these compounds.

Base your answers to questions 10 on the information below and on your knowledge of chemistry.

In a laboratory investigation, a solution that contains 13.2 grams of Pb(NO₃)₂ reacts completely with a solution that contains 12.0 grams of NaI, producing 18.4 grams of PbI₂ and an undetermined mass of a second product, NaNO₃. This reaction is represented by the balanced equation below.

Pb(NO₃)₂ + 2NaI → PbI₂ + 2NaNO₃

Base your answers to questions 11 on the information below and on your knowledge of chemistry.

The two naturally occurring isotopes of antimony are Sb-121 and Sb-123. The table below shows the atomic mass and percent natural abundance for these isotopes.

Antimony and sulfur are both found in the mineral stibnite, Sb₂S₃. To obtain antimony, stibnite is roasted (heated in air), producing oxides of antimony and sulfur. The unbalanced equation below represents one of the reactions that occurs during the roasting.

Sb₂S₃(s) + O₂(g) → Sb₂O₃(s) + SO₂(g)

Base your answers to questions 13 on the information below and on your knowledge of chemistry.

In 1828, Friedrich Wöhler produced urea when he heated a solution of ammonium cyanate. This reaction is represented by the balanced equation below.

Base your answers to questions 14 on the information below and on your knowledge of chemistry.

The balanced equation below represents the reaction of glucose, C₆H₁₂O₆, with oxygen at 298 K and 101.3 kPa.

C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(ℓ)

Base your answers to questions 15 on the information below and on your knowledge of chemistry.

Many breads are made by adding yeast to dough, causing the dough to rise. Yeast is a type of microorganism that produces the catalyst zymase, which converts glucose, C₆H₁₂O₆, to ethanol and carbon dioxide gas. The balanced equation for this reaction is shown below.