Physical Science Ch 10

Which of the following statements correctly describe the information conveyed by the balanced equation 16 Cu(s) + S8(g) → 8 Cu2S(s)?

- Cu and S8 are reactants, and Cu2S is the product. - 16 moles of Cu react with 1 mole of S8 to form 8 moles of Cu2S. - 16 atoms of Cu react with 1 molecule of S8 to form 8 formula units of Cu2S.

Which of the following statements are true concerning decomposition reactions?

- Decomposition reactions typically require heat or electrical energy to proceed. - Decomposition reactions have the general form XY → X + Y.

Along with energy, what are the products of hydrocarbon combustion?

H2O CO2

Which of the following is an example of an ion exchange reaction?

HNO3(aq) + KOH(aq) → KNO3(aq) + H2O(l)

Which two of the elements listed make up a molecule known as a hydrocarbon?

Hydrogen Carbon

Which of the following reactions are decomposition reactions?

2 HgO(s) → 2 Hg(s) + O2(g) 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

What is the percent by mass of oxygen in aluminum oxide (Al2O3)?

47.08%

How many tires are there in one mole of cars?

4tirescartirescar x 6.02 x 1023 cars

The number of entities in a mole (to 2 decimal places) is equal to ______ x 1023 and is called ______ number.

6.02; Avogadro's

Which of the following correctly reflects Avogadro's number?

6.02x10²³entities/mole

What is the general form of an ion exchange reaction?

AX + BY → AY + BX

Which of the following compounds are insoluble?

AgI SrF2

Balance the illustrated chemical equation by matching each substance to the correct coefficient. ____Al2S3(s) + ____H2O(l) → ____Al(OH)3(aq) + ____H2S(g)

Al2S3 - 1 H2O - 6 Al(OH)3 - 2 H2S - 3

How would you calculate the formula or molecular weight for a substance?

By adding the atomic weights of all the atoms involved

Which of the following options correctly describe how to calculate the molecular/formula weight of a compound?

- For Ca(NO3)2, the subscript 2 must be multiplied by 3 to determine the total number of oxygen atoms in the compound. - The atomic weight of a negative or positive ion is the same as the weight of the neutral element. - The formula/molecular weight is given by the sum of the weights of the component elements in the correct proportions.

Which of the following actions are permitted in balancing a chemical equation?

- Multiplying all coefficients by a common factor - Adding coefficients to formulas of reactants and products

Which of the following pieces of information are necessary to calculate the formula weight of a compound?

- The chemical formula of a compound - The atomic masses of each of the elements that make up the compound

Which of the following statements correctly describe the mole?

- The number of entities in a mole is called Avogadro's number. - The mole contains 6.02 x 1023 entities.

What is the meaning of a coefficient in a chemical equation?

- The number of molecules involved in the reaction - The ratio of combining volumes of each substance (if all reactants and products are gaseous)

Which of the following options correctly describes the formula weight of a compound?

The sum of the atomic weights of all the elements in the compound

What is the primary purpose of a chemical equation?

To describe a chemical reaction

If a soluble ionic compound (XY) is dissolved in solution, what are the products of this reaction?

X+ Y--

Select all the metals that are expected to displace Cu in CuSO4, with reference to the activity series for metals (shown).

Zinc Sodium

Select all the reactions that are expected to occur as written, with reference to the activity series for metals (shown).

Zn(s) + CuCl2(s) → ZnCl2(aq) + Cu(s) Pb(s) + 2 HCl(aq) → PbCl2(s) + H2(g)

The starting substances before a chemical reaction are known as the ______.

reactants

Match the gram-formula weight with the correct compound.

NaBr - 102.9 g MgSO4 - 120.4 g KOH - 56.11 g Al2O3 - 102.0 g

Match the appropriate flow of electrons with the correct term.

Oxidation - Loss of electrons by an atom Reduction - Gain of electrons by an atom

Match each compound with the correct mass percentage of hydrogen (H).

C6H6 - 7.7% CH3OH - 12.6% CH2O - 6.71%

How many wheels are there in one mole of bicycles?

2wheelsbicyclewheelsbicycle x 6.02 x 1023 bicycles

Which type of formula gives the simplest whole number ratio of atoms in a compound?

Empirical formula

Match each term about chemical formulas with the correct definition.

Empirical formula - Simplest whole number ratio of elements in a compound Molecular formula - Actual number of atoms of each element in a molecule Structural formula - Representation of the relative arrangement of atoms in a molecule

To balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid H2O, a student adds a subscript of 2 to the O in H2O. True or False: This is an acceptable method of balancing the above reaction.

False

Match the findings concerning the reactions of gases with the appropriate scientist.

Gay-Lussac - Reacting gases combine in small, whole number volumes when temperature and pressure are constant. Avogadro - Equal volumes of all gases at the same temperature and pressure contain the same number of molecules.

Match the definition with the appropriate term.

Gram-atomic weight - Mass in grams of one mole of an element that is numerically equal to its atomic weight Gram-formula weight - Mass in grams of one mole of the compound that is numerically equal to its formula weight Gram-molecular weight - Mass in grams of one mole of the molecule that is numerically equal to its molecular weight

The downward pointing arrow on the figure illustrates increasing ______.

ability to hold electrons

A more active metal will replace any metal ion in solution that it is ______ in the activity series. The reason this occurs is that metals lower on the list are better ______ agents than metals higher on the list.

above; oxidizing

A reaction in which a compound is broken down into its elements, simpler compounds, or elements and simpler compounds is called a(n) ______ reaction.

decomposition

A chemical ______ uses symbols to describe concisely a chemical reaction.

equation

Match the proper meaning to the term coefficient or subscript in a chemical reaction.

Coefficient - Number of molecules of a particular substance that reacts or is produced Subscript - Number of atoms of a particular element in a compound

Which of the following ionic compounds are soluble in water? See the table below for the names of common polyatomic ions. See the table of solubility rules to the right.

Pb(NO3)2 NH4Cl Na3PO4

Which of the following are possible products of an ion exchange reaction?

Solid Gas Water

The resulting new substances after a chemical reaction are known as the ______.

products

A redox reaction is one in which electrons are ______.

transferred

Gay-Lussac discovered that when gases combine at constant temperature and pressure, they do so in small ______ number volumes. Avogadro reasoned that gases behave in this fashion because equal volumes of gas contain an equal number of ______.

whole; molecules

Which of the following statements correctly describe replacement reactions?

- Replacement reactions involve an ion (or atom) in a compound that is displaced by an ion (or atom) of another element. - Replacement reactions occur because some elements have a stronger electron-holding ability than others. - XY + Z → XZ + Y is one generalized form of replacement reactions.

Which of the following statements are true about generalizations used when balancing chemical equations?

- The crossover technique can be useful when finding the least common multiple to balance an equation. - Look first at the chemical formula containing the most atoms and try to balance the atoms or compounds they were formed from or decomposed to.

Which of the following options correctly describe the symbols used in a balanced chemical equation?

- The symbol (l) indicates a liquid. - The symbol (aq) indicates an aqueous solution. - The symbol (g) indicates a substance in the gas phase.

Rank in order, from the first at the top, the steps necessary to calculate the mass percentage of oxygen in acetic acid (CH3COOH).

- Calculate the formula weight of acetic acid from its formula. - Multiply the number of atoms of oxygen in the molecular formula by the atomic weight of oxygen and then divide by the formula weight of acetic acid. - Multiply the answer by 100 percent to find the mass percentage of oxygen in acetic acid.

Which of the following statements about the molecular and empirical formulas of ionic and covalent compounds are true?

- Formulas for ionic compounds are never molecular formulas. - Formulas for covalent compounds are typically molecular formulas.

Which of the following symbols indicates a chemical solution in which water, H2O, is the solvent?

(aq)

Which of the following statements correctly describe a redox reaction?

- A redox reaction involves the transfer of electrons. - Reduction and oxidation must always occur together in a redox reaction.

Arrange the steps necessary to balance a chemical equation in correct sequence, starting with the first step at the top of the list.

- Write the formulas for the reactants and products - Inventory the number and types of atoms - Add coefficients in front of the reactants/products in order to balance the number of atoms - Inventory the number and types of atoms and adjust coefficients such that there are the smallest whole number coefficients

Which of the following statements about coefficients and subscripts in a chemical equation is true?

Coefficients can be changed when balancing a chemical equation.

Match the class of chemical compound with the appropriate type of chemical formula.

Ionic - Empirical formula Covalent - Empirical and molecular formula

A balanced chemical equation can be interpreted in terms of what types of ratios between reactants and products?

Mole Mass Molecular

Match each molecule with its molecular formula as illustrated in the figure.

Molecule A - H2O Molecule B - NH3 Molecule C - H2O2 Molecule D - CO2

How many compounds are formed in a combination reaction?

One

Match each general equation to the type of redox reaction it represents.

X + Y → XY - Combination XY → X + Y - Decomposition XY + Z → XZ + Y - Replacement

The upward pointing arrow on the figure illustrates increasing ______.

chemical energy

A reaction in which two or more species combine to form a single compound is called a(n) ______ reaction.

combination

In the presence of excess oxygen the ______ of a hydrocarbon produces CO2 and H2O.

combustion

Choose the three combinations that correctly fit in the two blanks in the following sentence: The mass in grams of one mole of a(n) ______ is numerically equal to its ______ weight.

compound; gram-formula element; gram-atomic molecule; gram-molecular

The term molecular weight can only be applied to a(n) ______ compound since ______ compounds do not consist of molecules. The correct term in this case is ______ weight.

covalent; ionic; formula

A balanced chemical equation is characterized by having the same ______ and ______ of atoms on both sides of the chemical equation.

number; type

The sum of the atomic weights of the elements in one unit of the compound is the ______ weight of an ionci compound.

formula

The mole relates the atomic weight of an element in u to the mass of 1 mole of that element expressed in ______. The mass of 1 mole of oxygen atoms is therefore equal to ______ (give to 3 digits and include the proper units).

grams, 16.0 g

A molecule that consists only of the elements hydrogen and carbon is classified as a compound called a(n) ______.

hydrocarbon

An ion exchange reaction occurs when two soluble ______ compounds mix and exchange ions to form a product that removes ______ from solution.

ionic; ions

When a soluble ionic compound is dissolved in solution, it dissociates into its respective ______

ions

Oxidation is defined as the ______ of electrons, whereas reduction involves the ______ of electrons.

loss; gain

Which of the following are useful generalizations to remember when balancing chemical equations?

- A correct formula of a compound cannot be changed by altering the number or placement of subscripts. - Atoms are neither lost nor gained, nor do they change their identity in a chemical reaction.

Which of the following statements correctly describe the information contained within a structural formula?

- A structural formula shows how the atoms of a covalent species are bonded together. - A structural formula contains the numbers and types of atoms in a molecule.

Which of the following items of information are necessary to calculate the mass percentage of an element in a given compound?

- Atomic weight of the element in question - Formula weight of the compound - Formula of the compound

Identify the coefficients required to balance the chemical equation. (Enter all numbers, including the digit 1 if required, and make sure you have the simplest ratio of coefficients.)

2; 1; 2

What is the gram-molecular weight of acetic acid (CH3COOH)?

60.05 g

Match the appropriate term concerning weight with the correct type of compound.

Ionic - Formula weight Covalent - Molecular weight

Which of the following options correctly describes an empirical formula?

The empirical formula of a compound gives the relative numbers of atoms in a compound.

The amount of substance that contains the same number of entities as the number of ______ in exactly 12 g of carbon-12 is referred to as a(n) ______.

atoms; mole

The coefficients in a balanced chemical equation can be interpreted as a(n) ______ ratio, or a molecular ratio. The coefficients can also be multiplied by the gram-formula, gram-molecular, or gram-atomic weights of each compound, molecule, or atom to give a(n) _______ ratio of reactants and products.

mole; mass

The ______ formula of a compound conveys the exact numbers of atoms of each element in the smallest unit of a substance.

molecular

A coefficient in a chemical equation has multiple meanings: it can tell you the number of ______ involved in the reaction and, for reactions in which the reactants and products are gaseous, the ______ of combining volumes at constant temperature and pressure.

molecules; ratios

A reaction that involves the displacement of an atom or ion in a compound by a different atom or ion is called a(n) ______ reaction.

replacement

When an acid reacts with a base, the products are a(n) ______, which is an ionic compound, and water.

salt