Chemistry Chapter 5 Homework

How many iron atoms are in 0.32 mol of Fe2O3?

3.9 × 10^23 iron atoms

How many moles of sulfur trioxide are formed from 3 moles of oxygen using the given balanced equation?2 SO2 + O2 → 2 SO3

6 mol of SO3

Potassium metal (K) reacts violently when added to water according to the balanced equation:2 K(s) + 2 H2O(l) → 2 KOH(aq) + H2(g). How many moles of H2O are needed to react completely with 7.54 mol of K?

7.54 mol of H2O

How many moles of sodium chloride (table salt, NaCl, molar mass 58.44 g/mol) are contained in a 1.00 lb box of table salt?

7.77 mol of NaCl

Suppose the theoretical yield in a reaction is 10.5 g and the percent yield is 75.5%. What is the actual yield of product obtained?

7.93 g

Blimps are essentially very large helium filled balloons. If a blimp contains 536 kg of helium, how many helium atoms are present inside the blimp?

8.06 x 1028 He atoms

The molecules A and B react according to the following chemical equation: A + 2B → C. Identify the limiting reactant under the reaction conditions shown in the molecular art below. A = large white circles B = small grey circles

A is the limiting reactant

2 Co(NO3)3(aq) + 3 (NH4)2S(aq) → Co2S3(s) + 3 NH4NO3(aq) is a properly balanced chemical equation.

False

A 100-g sample of the compound below contains less than 6.02 × 1023 molecules.

False

A 200-mg ibuprofen (C13H18O2) tablet contains greater than one mole of ibuprofen molecules.

False

A mole is a quantity that contains 6.02 × 10-23 atoms, molecules, or ions.

False

A mole of copper atoms has more atoms than a mole of lead atoms.

False

Consider the balanced reaction: 2 A + B → C, where the molar mass of B is less than the molar mass of A. It requires a smaller mass of A to completely react with given mass of B.

False

Consider the unbalanced chemical equation: NH3 + O2 → NO + H2O. It requires 55.4 g of NH3 to completely react with 156 g of O2.

False

In calculating the percent yield, both the actual yield and theoretical yield must be in units of grams.

False

In the reaction: Ni2+(aq) + Mg(s) → Ni(s) + Mg2+(aq), the species that undergoes reduction is Mg(s).

False

One term in a balanced chemical equation contains the coefficient 4 in front of the formula Mg3(PO4)2. This term represents that there are 12 Mg atoms, 4 P atoms, and 16 O atoms in this term.

False

The actual yield is the amount of product expected from a given amount of reactant based on the coefficients in the balanced chemical equation.

False

The balanced reaction: 4 NO2 + O2 + 2 H2O → 4 HNO3 states that four grams of nitrogen dioxide reacts with each gram of oxygen.

False

The molar mass of CaCO3 is greater than the molar mass of Ca(NO3)2.

False

The subscripts in chemical formulas are changed in order to balance a chemical equation.

False

To determine the overall percent yield in a synthesis that has more than one step, subtract the percent yield for each step from 100% yield.

False

To multiply two numbers in scientific notation, multiply the coefficients together and multiply the exponents in the powers of 10.

False

When the mass of a substance produced in a reaction must be calculated, first its number of moles is determined using mole ratios, and then Avogadro's number is used to convert moles to grams.

False

Complete the following table using the given balanced equation and the initial quantities of reactants. Equation: N2(g) + 2 O2(g) → 2 NO2(g) Initial quantities:5 molecules12 molecules0 moleculesMolecules used or formed:5 molecules used10 molecules used________

10 molecules formed

Which sample contains the largest number of molecules?

100 g of CH4

Aspartic acid is an amino acid used to synthesize proteins. What is the molar mass of aspartic acid shown below?

133.11 g/mol

Sodium fluoride can be produced from the reaction between sodium metal and fluorine gas. Which of the following represents the balanced chemical equation for this reaction?

2 Na(s) + F2(g) → 2 NaF(s)

Which reaction is a double displacement reaction?

3 Ca(OH)2 + Al2(SO4)3 → 3 CaSO4 + 2 Al(OH)3

How many moles of sulfur trioxide are formed from 3 moles of sulfur dioxide using the given balanced equation?2 SO2 + O2 → 2 SO3

3 mol of SO3

How many moles of carbon dioxide are in 211 g of carbon dioxide?

4.79 mol of CO2

How many moles of chloroethylene (C2H3Cl) contain 5.47 × 1026 molecules?

909 mol of C2H3Cl

Consider the oxidation of sodium metal to sodium oxide described by the balanced equation:4 Na + O2 → 2 Na2O. If 2.55 mol of sodium reacts, and 75.0 g of Na2O is produced, what is the percent yield?

94.9% yield

Beaker A contains 1 mole of iron atoms, and Beaker B contains 1 mole of lead atoms. Which statement concerning these two samples is known with certainty?

Beakers A and B contain an equal number of atoms.

In the balanced redox reaction: 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g), which species is oxidized?

C2H6(g)

Write a balanced chemical equation for the reaction of acetone (C3H6O) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O).

C3H6O + 4 O2 → 3 CO2 + 3 H2O

Identify the correct classification for the reaction 2 PbSO4 → 2 PbSO3 + O2

Decomposition

In the balanced redox reaction: 2 Cu(s) + S(s) → Cu2S(s), how many electrons are gained or lost by each copper atom?

Each copper atom loses one (1) electron

Identify the species that is oxidized and the species that is reduced in the reaction:2 I- + Cl2 → 2 Cl- + I2.

I- is oxidized and Cl2 is reduced.

Identify the correct product that would complete the following double displacement reaction: NaOH + HBr → ________ + H2O

NaBr

In the balanced redox reaction: 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g), which species is reduced?

O2(g)

A 100-g sample of the compound below contains greater than one mole of molecules.

True

A chemical equation is balanced by adding coefficients in front of some formulas so that the number of atoms of each element is equal on both sides of the equation.

True

Combustion reactions are redox reactions.

True

In a chemical reaction, the actual yield of a product may be reduced by side reactions.

True

In redox reactions, metals tend to undergo oxidation.

True

In the reaction: Ni2+(aq) + Mg(s) → Ni(s) + Mg2+(aq), the oxidizing agent is Ni2+(aq).

True

The law of conservation of mass states that ________.

atoms cannot be created or destroyed in a chemical reaction

The actual yield of a product in a chemical reaction should not exceed its theoretical yield.

True

The balanced reaction: 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s) is an oxidation-reduction reaction.

True

The balanced reaction: 4 NO2 + O2 + 2 H2O → 4 HNO3 states that four moles of nitrogen dioxide react with each mole of oxygen.

True

The electric current generated in batteries used for portable electronic devices and pacemakers results from redox reactions.

True

The formula weight of a compound is the sum of the atomic weights of all the atoms in a compound, reported in atomic mass units.

True

The mass of one ethanol (C2H6O) molecule is 7.65 × 10-23 grams.

True

Tin (II) fluoride can be made by the following reaction: Sn(s) + 2 HF(g) → SnF2(s) + H2(g). What is the maximum amount of SnF2 that can be produced when 0.480 moles of Sn are mixed with 0.720 moles of HF?

0.360 moles of SnF2

What is the mass of 3.81 mol of PH3?

130. g

Complete the following table using the given balanced equation and the initial quantities of reactants. Equation: S8 + 12 O2 → 8 SO3 Initial quantities:30 molecules30 molecules0 moleculesMolecules used or formed:2 molecules used24 molecules used________

16 molecules formed

Which chemical equation is properly balanced?

2 SO2 + O2 + 2 H2O → 2 H2SO4

Which quantity has the greatest mass?

2.0 mol of Na2O

How many carbon atoms are in 77.28 g of ethane (C2H6)?

3.094 × 10^24 carbon atoms

A balanced chemical equation tells the number of ________ of each reactant that combine and the number of ________ of each product formed.

moles; moles