Chem 6

Although elements in Group 13 of the periodic table typically form ions with a charge of +3, some members of the group also form ions with a charge of ______.

+1

Select all the conversion factors that correctly represent the molar relationships in this balanced equation 2Al + 3Cl2 → 2AlCl3.

-2 mol AlCl3/3 mol Cl2 -2 mol Al/3 mol Cl2

Correctly place the steps in order for determining the molecular formula of a compound from combustion analysis data, if the approximate molar mass is known.

1. Determine the empirical formula 2. Use the emprical 3. Divide 4. multiply each

Correctly order the steps necessary to determine the empirical formula of a compound from combustion analysis data.

1. Determine the masses of C 2. Determine the mass of O 3. Determine the number of moles 4. Covert the subscripts in the formula

Correctly order the steps used in a combustion analysis experiment to determine the empirical formula of an organic compound.

1. The mass 2. The sample 3. The CO2 and H2O 4. The mass of each product is determined

Correctly order the steps necessary to solve for the mass of a product, or second reactant required, given the mass of one of the reactants in a chemical process. Start with the first step at the top of the list.

1. Write a balanced 2. convert the given mass into moles 3. Covert the moles

Correctly order the steps necessary to balance a chemical equation.

1. write an unbalanced equation 2. Balance 3. Adjust the coefficients 4. Do a final check

B2 + 2AB → 2AB2 In the balanced reaction equation above, if 1.0 moles of B2 and 1.5 moles of AB are allowed to react to completion, what is the maximum amount of AB2 that can form?

1.5 moles

2S (s) + 3O2 (g) → 2SO3 (g) Which of the following gives the correct setup for calculating the number of moles of SO3 that will form from the complete reaction of 1.5 mol of O2, according to the balanced reaction equation above?

1.5*2 /3

3H2 (g) + N2 (g) → 2NH3 (g) Calculate the mass of NH3 produced by the complete reaction of 2.55 g of H2 with excess N2 according to the equation above.

14.4 g

When the following chemical equation is balanced correctly, what is the correct coefficient for each species? (Enter ALL numbers, including the digit 1, if required.) SO2(g) + O2 (g) → SO3 (g)

2 1 2

What is the empirical formula of a compound containing C, H, and O if combustion of a 0.500-g sample of the compound produces 0.955 g CO2 and 0.587 g of H2O? (Put a number in every blank, even if it is a 0 or 1.) C H O

2 6 1

Given the balanced equation below, determine the moles of HCl required and the mass of AgCl formed from the complete reaction of 18.3 g of Ag2S. Ag2S (s) + 2HCl (aq) → 2AgCl (s) + H2S (g)

21.2 g of AgCl 0.148 mol HCl

Butane burns in oxygen according to the following balanced reaction equation: 2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10H2O (g) When a 5.6-mole sample of butane reacts with O2, which of the following amounts of other reaction species are correct?

36 moles O2 22 moles CO2

Which of the following statements are correct interpretations of the balanced equation 4C (s) + S8 (s) → 4CS2 (l)? Select all that apply.

4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2. Carbon and S8 are reactants and CS2 is the product. 4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2.

2Al2O3 (s) → 3O2 (g) + 4Al (s) Given the balanced equation above, match the quantities of reactants and products.

5.0 - 7.5 2.0 - 1.5 6.0 - 4.5

A reaction is expected to produce 83.5 g of CaCO3. The percent yield is recorded as 62.5%. What is the actual mass of CaCO3 obtained?

52.2 g

A particular reaction is expected to yield 125 g of Ca. The actual amount of Ca obtained is equal to 105 g. Calculate the % yield for the reaction.

84.0%

A + 2B → C Reactants A (blue) and B (red) react according to the balanced equation above. Which of the following statements are correct?

A is the reactant in excess. B is the limiting reactant.

Balance the unbalanced equation below, using lowest possible whole-number coefficients, then match each substance to the correct coefficient as indicated. Al2S3 (s) + H2O (l) → Al(OH)3 (aq) + H2S (g)

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

Which of the following properties are associated with the alkali metals? Select all that apply.

Alkali metals are unusually soft. Alkali metals are very reactive.

Which of the statements below, concerning periodic trends in the properties of elements, are correct?

All elements in Group 17 form -1 ions. Elements with low ionization energies tend to form positive ions. Elements in Period 2 tend to have somewhat different properties from the rest of the elements in their groups.

Match each element to the charges of its common cations.

Aluminum - +3 Indium - +1 and +3 Lead - +2 and +4

Rank the following elements in decreasing order of first ionization energy (IE1). Place the element with the highest value of IE1 at the top of the list.

Be Mg Na

Select all the statements that correctly describe the properties of the Group 15 elements.

Bismuth is the only metal in the group. Nitrogen forms the ion N3- in binary ionic compounds. Both nitrogen and phosphorus combine with oxygen to form oxides.

Which of the following statements exemplifies a diagonal chemical relationship between elements of the periodic table?

Boron and silicon both act as semiconductors.

Which of the following statements correctly describe the Group 13 elements? Select all that apply.

Boron is unreactive with water and oxygen. Most of the Group 13 elements are metals.

10.00 grams of an organic compound containing C, H, and O undergoes combustion analysis and yields 24.48g CO2 and 3.33g H2O. If the molar mass of the compound is 108.1 g/mol, what is the molecular formula of the compound?

C6H4O2

Hydrocarbons are compounds that contain only carbon and hydrogen. Combustion of a sample of a particular hydrocarbon gave 5.86 g of CO2 and 1.37 g of H2O. What is the empirical formula of the hydrocarbon?

C7H8

What type of reaction is described by the equation shown below? CS2 (l) + 3O2 (g) → CO2 (g) + 2SO2 (g)

Combustion

Which statement does NOT correctly describe a step in determining the empirical formula of a compound from combustion analysis data?

Determine the mass of a third element, if present, from the mass of its oxide produced in the combustion.

Unlike most metals, lithium and magnesium both react with N2 to form ionic nitrides. Which of the following observed relationships in the periodic table does this illustrate?

Diagonal relationships are often observed between Period 2 elements in Groups 1A, 2A, and 3A and the elements diagonally below them in Period 3.

A student has done experiments to determine the empirical formula and the approximate molar mass of a substance. Which of the following methods should be used to determine the molecular formula?

Divide the approximate molar mass by the empirical formula mass.

Elements in the same group in the periodic table often have similar chemical reactivity. Which of the following statements is the best explanation for this observation?

Elements in the same group have the same valence electron configuration.

What information can be obtained from a combustion analysis? Select all that apply.

Empirical formula of an organic compound Percent composition of an organic compound

True or false: In order to balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid H2O, a student adds a subscript of 2 to H2O (forming H2O2). This is an acceptable method of balancing the reaction described.

False

In which of the following groups in the periodic table would you expect the elements to have the greatest range of different chemical properties?

Group 15

In the reaction shown, what does the symbol Δ indicate? CuCO3 (s) −→Δ→Δ CuO (s) + CO2 (g)

Heat is required for this reaction.

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

Inserting coefficients before the formulas of reactants and products Multiplying all coefficients by a common factor

Which of the elements below would have similar chemical properties to those of sodium (Na), and which would be most different? Rank the elements in order of their similarity to Na, with the most similar at the top of the list.

K Ca Ti Ne

Which Group 15 elements are classified as nonmetals? Select all that apply.

N P

Rank the elements below in order of their metallic character, with the least metallic at the top of the list.

N P As Bi

Aqueous solutions of calcium hydroxide and sodium phosphate react to form aqueous sodium hydroxide and solid calcium phosphate." In the reaction represented by the statement above, what are the reactants?

Na3PO4 Ca(OH)2

In a balanced chemical equation, which of the following must be the same on both sides of the equation?

Number of atoms of each element

Select all the statements that correctly describe the properties of the Group 16 elements.

Oxygen forms a large number of molecular compounds with other nonmetals. In its elemental form, oxygen forms O2 molecules, whereas sulfur forms S8 molecules.

Which elements from Groups 13 and 14 can form cations with more than one possible charge? Select all that apply.

Pb In Sn

In the process shown below, why is the formula for water placed above the reaction arrow? C2H5OH (l) −→−H2O→H2OC2H5OH (aq)

Placing water above the arrow indicates that it is only acting as a solvent.

Select all the statements that correctly describe Group 14 elements.

Sn and Pb react with acids to produce hydrogen gas. Group 14 elements do not react readily with H2O. Sn and Pb form cations with charges of +2 and +4.

Select all of the statements below that correctly describe the Group 1 metals.

Some of the alkali metals can combine with oxygen to form compounds with the formulas M2O, M2O2, and MO2. Hydrogen is not included in the classification "alkali metals." The alkali metals are reactive with water and oxygen.

The elements in Group 17 of the periodic table have very similar chemical properties, while the elements of Group 14 vary significantly from one another in their properties. Which statement below correctly explains this difference?

The elements of Group 17 are all nonmetals, while Group 14 contains nonmetals, metalloids, and metals.

Which of the following statements correctly describe the limiting reactant in a reaction? Select all that apply.

The limiting reactant limits the amount of product that can form. The maximum amount of product formed is the amount that can be formed from the limiting reactant.

Which statement below about Group 14 (4A) elements is NOT correct?

The most stable cation of germanium is Ge2+.

The noble gases are generally unreactive. Which statement best explains this observation?

The noble gases have high ionization energies and negative electron affinities, so they usually neither lose nor gain electrons.

Select all that apply Select all the statements that correctly describe the symbols used to write a balanced equation.

The symbol (s) is used for a powdered substance. The symbol (g) indicates a substance in the gas phase.

In an experiment, a student calculates the maximum expected yield of her product to be 3.2 grams. However, when she weighs the purified product, she finds that she only has 2.8 grams, or only 88% of the maximum expected. Match each type of yield to its numerical value.

Theoretical yield - 3.2 Actual yield - 2.8 Percent yield - 88

Match each type of reaction yield with the correct definition.

Theoretical yield - the maximum possible amount of product Actual yield - Amount of product percent yield - fraction equation

Menthol (molar mass = 156.3 g/mol) is a compound of carbon, hydrogen, and oxygen. When 0.1595 g of menthol underwent a combustion analysis, 0.449 g of CO2 and 0.184 g of H2O were produced. Select all the statements that correctly interpret these data.

There are 2.04 × 10-2 moles of H in the sample. The mass of C present is 0.123 g.

Select all the properties that are typical for alkaline earth metals.

They tend to form +2 cations in ionic compounds. They tend to react with acids to produce hydrogen gas.

Which of the following statements correctly interpret the balanced chemical equation 4HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2H2O (l) + Cl2 (g)? Select all that apply.

Water is both a solvent and a product in this reaction. HCl is a reactant in this equation. The MnCl2 produced is dissolved in water.

Which of the following steps would be required to convert between the masses of two substances that are related through a chemical reaction? (For example, calculating the mass of product formed from the mass of a reactant.) Select all that apply.

Write a conversion factor using the coefficients from the balanced equation, and convert to moles of the second substance. Write a balanced chemical equation for the reaction. Convert from the given mass to moles of the same substance.

Which of the noble gases form stable oxides or halides? Select all that apply.

Xe Kr

Oxygen forms many molecular compounds with other nonmetals. As a group, nonmetal oxides tend to be ______.

acidic

Match each symbol used in writing a chemical equation with its correct meaning.

arrow - indicates conversion of reactants to products s - indicates soild state aq - indicates dissolved in H20 triangle - indicates reaction is heated l - indicates liquid state

In a(n) reaction, a single product is formed from two or more reactants. The opposite of this reaction type is a(n) reaction, in which a single reactant produces two or more products.

combination decomposition

Match each reaction type with its distinguishing feature

combination - two or more reactants combine to form a single product decomposition - a single reactant forms two or more products combustion - a reactant rapidly reacts with 02

Match each of the following reactions with its general type.

decomposition - CuCO3 combination - PF3 combustion - C2H4

The reactant in a reaction is one that limits the amount of product formed. This reactant will be completely used up in the reaction. Any reactants that are not used up are said to be reactants.

limiting excess

N2O4 → 2NO2 In the reaction represented by the chemical equation above, NO2 is the formula of the ______ and N2O4 is the formula of the ______.

product, reactant