Chemistry Unit Review

Which statement accurately describes covalent bonds?

• Covalent bonds are formed by metals and nonmetals.

• Covalent bonds are typical of carbon compounds.

• Covalent bonds are created by the attractions between oppositiely charged ions.

• Covalent bonds break apart when dissolved in water and allow for the conduction of electricity.

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In solid NaCl, each sodium ion is surrounded by six chlorine ions and each chlorine ion is surrounded by six sodium ions. This arrangement results in a

• malleable noncrystalline structure.

• ductile, malleable solid with mobile electrons.

• weak crystalline solid that conducts electricity.

• high melting point and strong intermolecular forces.

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During a physical science lab investigating chemical reactions, several students placed a 30g antacid tablet in a 30g zip-lock bag. They recorded the masses of the tablet, and the bag. Then they added 50 grams of water and quickly sealed the bag. The tablet began to fizz and soon disappeared. The bag was filled with gas. If the mass of the liquid after the reaction is completed is still 50 grams, how much gas is produced?

• 30 grams

• 50 grams

• 80 grams

• 90 grams

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Sodium chloride, NaCl, is formed when a sodium atom transfers its electron to a chlorine atom. The difference in charge between the two atoms creates a(n) ___________ attraction that bonds them together.

• electrostatic

• elementary

• gravitational

• nuclear

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Use the IUPAC nomenclature rules to give the name for this compound - Ca₂S₃.

• calcium sulfide

• calcium (II) sulfide

• dicalcium trisulfide

• calcium (III) sulfide

The decomposition of water into hydrogen gas H₂ and oxygen gas O₂ can be modeled by the balanced chemical equation

• H₂ + O₂ → H₂O

• H2O → H2 + O2

• 2H₂ + O₂ → 2H₂O

• 2H₂O → 2H₂ + O₂

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Calcium metal reacts with a potassium chloride solution to form calcium chloride and potassium ions. Balance this reaction.

___Ca_(s) + ___KCl_(aq) → CaCl_2(s) + ___K⁺_(aq)

• 1, 2, 1, 2

• 1, 2, 1, 1

• 1, 1, 1, 1

• 2, 1, 2, 1

The electrostatic attractions in crystalline salts, such as sodium chloride, are formed by __________ between positive and negative ions.

• sharing electrons

• a sea of electrons

• dipole attractions

• transferring electrons

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4 Al + 3O₂ → 2Al₂O₃

What does the "3" in front of O₂ stand for?

• It indicates that there are 5 oxygen atoms after you add the coefficient and the subscript.

• It indicates that that there are are total of 6 oxygen atoms bonded together.

• It indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction.

• It indicates that there are 3 separate oxygen molecules in the reaction.

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The term "3 FeCl₂" in a balanced equation says

• that there are three iron(II) ions and two chloride ions bonded together.

• that there are three iron(II) ions and 6 chloride ions bonded together.

• that there are three formula units, each consisting of two chloride ions bonded to an iron(II) ion

• that there are three particles, each consisting of three iron atoms and 6 chlorine atoms.

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