Chemistry Readings 3A
Given the balanced equation 3H2(g) + N2(g) = 2NH3(g) , calculate the mass of NH3 produced by the complete reaction of 2.55 g of H2
14.4 g Reason: 2.55 g H2x 1 mole H2/ 2.016 H2 x 2mol NH3 / 3 mol H2 x 17.03 g NH3/ 1 mol NH3 = 14.4 g
Which of the following species will be present in an aqueous solution of Na2CO3?
Co3^2- Na^+
In a solution ____.
Components are mixed uniformly together One or more substances are dissolved in a solvent
H2O ----->
Dissolves in water
Nonelectrolyte
Does not dissociate or ionize in water and does not conduct an electric current in aqueous solution
Which of the following statements correctly interpret the balance chemical equation 4HCl (aq) +MnO2(s) = MnCl2 (aq) + 2H2O (g) +Cl2 (g)? Select all that apply
HCl is a reactant in this equation The MnCl2 produced is dissolves in water
An electrolyte is any substance that conducts an electric current _____.
In an aqueous solution
C3H8O3
Nonelectrolyte
Which of the following options correctly describe electrolytes and nonelectrolytes? Select all that apply.
Nonelectrolytes neutral molecules or atoms in solution Electrolytes include soluble ionic compounds and acids Electrolytes produce charged particles in aqueous solution
CO3^2-
Soluble except with Ca^2+, Sr^2+. Ba^2+, Ag^+, and Pb^2+
MgCl2
Soluble ionic species
KClO4
Soluble salt, will not appear in the net ionic equations
K3PO4
Soluble; an exception to the usual behavior of the anion
Mg2+ and Cl-
Spectator ions
Which statement correctly defines stoichiometry?
Stoichiometry is quantitative study of reactants and products in a chemical reaction
Which of the following statements correctly describe the percent yield in a chemical reaction? Select all that apply
The actual yield is almost always less than the theoretical yield. % yield = actual yield / theoretical yield x 100
What structural feature will allow substance to conduct an electric current?
The presence of charge particles that are free to move independently
Why does an aqueous solution of an ionic substance conduct an electric current?
The solution contains ions that are free to move
Which of the following statements correctly describe a molecular equation? Select all that apply.
This equation represents all reactants and products as if they were intact and undissociated. A molecular equation will not include any charges on any of the species.
Place the steps required to determine whether or not a precipitate forms when two solutions are mixed in the correct order. Start with the first step at the top of the list.
1. Note the ions present in the reactants 2. Consider possible cation-anion combinations 3. Use the solubility rules to determine whether or not either of the combinations gives an insoluble salt
When hydrogen gas is passed over powdered iron(III) oxide, iron metal and water vapor are formed. Which of the following is the correct balanced equation for this process?
3H2(g) + Fe2O3 (s) = 2Fe (s) +3H2O (g)
Reactants
A starting material in a chemical reaction
Actual yield
Amount of product obtained experimentally from a chemical reaction
Compound B2 (represented by the red spheres) reacts with AB, as shown in the illustration. From the illustration, the reactant in excess is ____, and the limiting reactant is _____.
B2; AB
An electrolyte is a substance that produces ___ in aqueous solution, allowing the solution to conduct an electric current
charged particles
Placing a coefficient in front of a substance
does not change the identity of the substance
A reaction in which one or more precipitates form when the aqueous solutions of two ionic compounds are mixed is called a(n) ____ displacement reaction, since both pairs of ions exchange partners. Another name for this type of reaction is a(n) _____ reaction.
double; metathesis
A substance that conducts an electric current when dissolved in water is called a(n) ____.
electrolyte
An acid is a substance that produces ____ when dissolved in water. This process, called ____, involves the breaking of a covalent bond to an ionizable hydrogen atom
ions; ionization
Substance to the right of the arrow
product
The maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature is referred to as the ____.
solubility
SO4^2-
soluble except with Ag^+, Pb^2+, Cu^+, and Hg2^2+
Na^+
soluble in all combinations
----> means
to yield
CH3CH2COOH
weak electrolyte
Identify the whole number coefficients required to balance the chemical equation P4(s) +O2(g) = P2O5 (s) correctly. (Enter ALL numbers, including the digit 1 required, and make sure you have the simplest ratio of coefficient
1 -- P4 5 -- O2 2 -- P2O5
An electrolyte is ____.
A substance that conducts an electric current in aqueous solution
Which of the following options identify the correct coefficients required to balance the reaction illustrated? In the illustration, carbon is black and oxygen is red. Select all that apply
CO2 is produced and has the coefficient 2 The reactant CO must have the coefficient 2
When writing a net ionic equations for a reactions _____
Charges must be included with the formulas for the ions Spectator ions are omitted
Products
Ending materials in a chemical reaction.
Which of the following actions are permitted in balancing a chemical equation? Select all that apply
Inserting coefficients in front of formulas of reactants and products Multiplying all coefficient by a common factor
Cl^-
Insoluble except with Group 1A cations or NH^4+
Strong acids are classified as
Strong electrolytes
Weak acids are classified as
Weak electrolytes
Percent yield
actual/theoretical x 100
A chemical equation is a statement using chemical _____ that expresses both the identities and the relative ____ of the reactants and products involves in a chemical or physical change.
formula; quantity
PbSO4
insoluble; an exception to the usual rule
A(n) ____ equation shows ALL soluble ionic substances dissociated into ions. Both the ____ and electrical ____ must be balanced in this type of equation.
ionic; atoms; charges
Strong acids and bases ____ completely to form _____ in water. The resulting solution conducts electricity well; hence these compounds are classified as ____ electrolytes
ionize; ions; strong
In aqueous solution, a soluble ionic compound dissociates into its component _____, which are free to move independently, allowing the solution to conduct electricity. Soluble ionic compounds are therefore classified as ____.
ions; electrolytes
NaNO3
soluble; both ions always give soluble salts
Given the balanced equation P4(s) + 5O2(g) = 2P2O5(s) Select all the conversions factors that correctly represents the molar relationships in this equation
2 mol P2O5/ 1 mol P4 1 mol P4/ 5 mol O2
Carbon dioxide gas and water are produced when acetylene burns in oxygen. What of the following options given the correct balanced equation for this process? Select all that apply
2C2H2 +5O2 = 4CO2 +2H2O 2C2H2(g) +5O2(g) = 4CO2(g) +2H2O (g)
Given the balanced equation 2AgNO3 (aq) + Zn (s) = 2Ag(s) + Zn (NO3)2 (aq) determine the moles of Zn required and the mass of Ag formed the complete reaction of 9.02 g of AgNO3
5.73 g of Ag are formed 2.65 x 10^-2 mol Zn are required
A given reaction has a theoretical yield of 4.26 g of bromobenzene, C6H5Br. The actual amount of bromobenzene isolated from the reaction is 3.15g. Calculate the percent yield for the reaction.
73.9% Reason: 3.15g/ 4.26g x 100 = 73.9%
A particular reaction is expected to yield 125g of calcium. The actual amount of calcium obtained is equal to 105g. Calculate the percentage yield for the reaction
84.0% Reason: 105g/ 125g x 100 = 84.0%
Which of the following options correct describe the symbols used to write a balanced equation? Select all that apply
A liquid is indicated by the symbol (l) The symbol (g) indicated by the symbol (g)
Which of the following correctly defines a precipitate?
A solid product that separates from a solution
What is an electrolyte?
A substance that, when dissolved in water, results in a solution that can conduct electricity
The general formula HX is often used to represent an acid. Which of the following options correctly describe the ionization of an acid in aqueous solution? Select all that apply.
Acid molecules break apart to form ions due to the strong interaction between the ionizable H and H2O molecules. The covalent H-X bond is broken as the H2O molecules attract the H.
Which of the following statements correctly describe the information conveyed by the balanced equation 16Cu(s) + S8(g) = 8Cu2S(s)? Select all that apply
Cu and S8 are the reactants and Cu2S is the products 16 atoms of Cu react with 1 molecule of S8 to form 8 formula units of Cu2S 16 moles of Cu reacts with 1 mole of S8 to form 8 moles of Cu2S
True or False: The balanced equation below represents a metathesis reaction. Pb(NO3)2(aq) + 2NaCH3COO(aq) = Pb(CH3COO)2(aq) +2NaNO3(aq)
FALSE Reason: This reaction is NOT a metathesis reaction. A metathesis reaction is one in which two compounds exchange partners. Although it appears that this happens in the equation shown here, because both products are soluble in water all the ions simply remain dissociated and separate in solution. No actual exchange of partners has occurred.
Which of the marked H atoms in the following formulas are readily ionizable in aqueous solution? Select all that apply.
HCOO__H C6H5COO__H H__3PO4
Which of the marked H atoms in the following formulas are readily ionizable in aqueous solution? Select all that apply
HCl H2CO3 HCN
Which of the following represent reversible processes or reactions? Select all that apply.
HF(aq) ⇌ H+(aq)+ F-(aq) NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
Which of the following are strong electrolytes? Select all that apply.
HNO3 KBr H2SO4 CaCl2 Fe(NO3)3
Which of the following cations often produce water-insoluble salts, even with anions such as SO4^2-?
Hg2^2+ Pb^2+ Ag^+
Which of the following statements correctly describe hydration? Select all that apply.
Hydration stabilizes ions in solution. Hydration is the result of a strong interaction between solute particles and H2O molecules. An ion surrounded by H2O molecules in solution is hydrated.
Which of the statements below are contained in the following chemical equation? Select all that apply C(s) +H2O(g) = CO(g) +H2(g)
Hydrogen gas is being produced in the reaction Carbon (C) is reacting with water
An electric current is a flow of change through a medium, can be carried by the movement of ___. (Select all that apply).
Ions; Electrons
The molecular equation for a reaction ____. (Select all that apply).
Is the least accurate representation of the actual chemical change occurring Shows all species as if they were intact, undissociated molecules in solution
Which of the following ions typically form water-insoluble salts, except when partnered with a Group 1A cation or NH4^+?
OH- CO3^2- PO4^3-
A solid that forms in a reaction and separates from solution is called a(n) ____.
Precepitate
Which of the following statements does NOT describe information that can typically be obtained from a chemical equation?
The amount of energy required to initiate the reaction
Theoretical yield
The amount of product calculated from the molar ratio in the balanced chemical equation
which of the following statements correctly describe an ionic equations? Select all that apply
The ionic equations includes all ions, including spectators ions Charges and atoms must be balanced in an ionic equation Charges must be included where relevant in an ionic equations
Which of the following options correctly describe a precipitation reaction? Select all that apply
This type of reaction forms one or more insoluble products. This type of reaction often occurs in aqueous solution. This type of reaction usually involves ionic compounds.
HCOOH
Weak electrolyte
insoluble ion combination
Will precipitate from solution
Which of the following steps would be required to convert between the masses of any two substances involved in the same chemical reaction? 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 equation for the reaction Convert from the given mass to moles of the same substance
Cation-cation
cannot combine to form a compound
Multiplying or dividing all coefficients by a common factor
does not change whether or not an equation is balanced
A reversible reaction in a closed system can reach a state of chemical _____ in which the rate of the forward reaction is equal to the rate of the reverse reaction.
equilibrium
C2H5OH
nonelectrolyte
A chemical equation must be balanced. This means that the same ___ and ___ of atoms must appear on both sides of the equation
number; type
KOH
strong electrolyte
For any given reaction, the ____ yield represents the maximum amount of product that can possibly be produced. The ____ yield describes the amount of product that is isolated when the reaction is carried out in practice.
theoretical; actual
Soluble ion combination
will not form a precipitate
Anion
δ+ of H2O
Cation
δ- of H2O
Which of the following compounds are SOLUBLE in water? Select all that apply
(NH4)2CO3 K2SO4 Ca(ClO3)2
Given the balanced equation 4NH3 (g) + 7O2 (g) = 4NO2 (g) +6H2O (g), calculate the mass of H2O produced by the complete reaction of 3.19 g of NH3.
5.06 g Reason: 1 mol NH3/ 17.03g NH3 x 6mol H2O/4 mol NH3 x 18.02gH2O/ 1 mol H2O = 5.06g H2O
A particular reaction is expected to yield 125 g of calcium. The actual amount of calcium obtained is equal to 105 g. Calculate the percentage yield for the reaction.
84.0% 105g/125g x 100 = 84.0%
Which of the following statements correctly describe a net ionic equation? Select all that apply
A net ionic equation shows only the chemical change that is taking place in a reaction A net ionic equation shows only the species that have undergone a charge in the reaction, and any products that form
Why is an acid able to produce ions in aqueous solution?
An acid (H-X) dissociates into H^+ and X^-. Each ion is surrounded by water and stabilization by hydration
Which of the following options correctly describe an aqueous solution? Select all that apply
An aqueous can have two ore more different solutes The solvent of an aqueous solution is always water An aqueous solution is a homogeneous mixture
What is an aqueous solution?
An aqueous solution can have two or more different solutes An aqueos solution is a homogeneous mixture The solvent of an aqueous solution is always water
Which of the following statements correctly describe the steps used to determine which reactant in a given reaction is limiting? Select all that apply
Calculate the molar masses of any reactants for which a mass has been given Calculate the amount of product that could be formed from each reactant The reactant that produces the least amount of possible product is the limiting reactant
Which of the following options correctly describe how ionizable H atoms are typically designated in the formula for an acid? Select all that apply
For an organic acid, the designation -COOH typically indicates ionizable hydrogen atoms. For inorganic acids, the ionizable hydrogen atoms are typically at the beginning of the formula.
Weak acids
From very few ions in aqueous solution
Consider the image shown. H2 (white atoms) reacts with O2 (red atoms to form water according to the balanced equation below. Based on the amount of H2 and O2 shown in the image, which is the limiting reactant? 2H2 + O2 = 2H2O
H2 (white atoms)
Which of the following shows a reversible reaction?
HCOOH(aq) + H2O(l) ⇌ H3O+(aq) + HCOO-(aq)
Which of the following statements correctly describe a chemical equation? Select all that apply
In a chemical equation, reactions, and products are represents by symbol or molecular formulas The physical states of the reactants and products should be indicated in a chemical equation
Ag2CO3
Insoluble; not an exception to the usual behavior for the anion
Strong acids
Ionize completely in aqueous solution
Pb2+ and Cl-
Ions that combine to forma precipitate; will appear in the net ionic equations
Which of the following correctly defines spectator ions?
Ions that do not participate in the reactions although they are present
Which of the following balanced equations correctly represents the dissociation of K2SO4 in water?
K2SO4(s) = 2K^+(aq) + SO4^2- (aq)
Identify ALL the spectator ions in 3Ca(CH3COO)2(aq) + 2K3PO4(aq) = Ca3(PO4)2(s)+ 6KCH3COO(aq)
K^+ CH3COO^-
Which of the following balanced equations correctly represents the dissociation of Nu(NO3)2 in water?
Ni(NO3)2 = Ni^2+ (aq) + 2NO3- (aq)
Ba2+ and SO4^2-
Reactant ions
K+ and ClO4-
Reactant ions; will not appear in the net ionic equation
BaSO4
Solid product
PbCl2+
Solid product; will appear in the net ionic equations
Na2SO4
Strong electrolyte
Why is the formula for acetic acid typically written as CH3COOH instead of C2H4O2?
The H of the COOH group is ionizable, while the H atoms bonded in the CH3 group are not.
Which of the following statements correctly describe a chemical system at equilibrium?
The forward and reverse reactions occur at equal rates. There appears to be no visible change in the concentrations of reactants or products.
Which of the following reactions is readily reversible and reaches chemical equilibrium under ordinary conditions?
The ionization of CH3COOH in aqueous solution
Which of the following options correctly describe the limiting reactant in a reaction? Select all that apply
The limiting reactants the amount products that can form The maximum amount of product formed is the amount that can be formed from the limiting reactant
When an ionic compounds is added to water, the ____ will be attracted to the partially positive H atom atom of water and the ___ will be attracted to the partially negative O atom of water. As the compound dissolves ions separate from the each other, or ____.
anions; cations; dissociate
Spectator ions...
are omitted in a net ionic equation remain unchanged in a chemical reaction are included in the ionic equation for the reaction
An ionic equation shows species ____ in solution. This equation is the ____ accurate representation of the chemical change occurring.
as they actually exist; most
Changing the subscripts of a substance
changes the identity of the substance
The ___ reactant in a reaction is one that limits the amount of product formed. This reactant will be completely used up in the reaction
limiting
Acids (e.g., HCl) are ___ compounds that nonetheless produce ions in aqueous solution as the H2O molecules attract the ionizable hydrogen atoms in the compounds, causing the ____ H-X bond to break. Acid's are therefore electrolytes.
molecular; covalent
A chemical equation that shows all reactants and products as intact, undissociated compounds is called a(n) ___ equation. The name is misleading because not all compounds are composed of _____.
molecular; molecules
C6H6(l) +3Br2(l) = C6H3Br3(l) + 3HBr(g) According to this equation, 1 molecule of C6H6 reacts with 3 ____ of Br2; while 1 ____ of C6H6 produces 1 mole of C6H3Br3
molecules; mole
Cation-anion
new ion combination that may form a precipiatate
Spectator ions undergo ____ in a chemical reaction and will be omitted from the ___ equation for the reaction
no overall charge; net ionic
H of Ch3 group
not readily ionizable
When a reversible chemical reaction occurs in a closed system, a state of dynamic chemical equilibrium is reached when the ____ of the forward and reverse reactions are equal. At this point the ____ of the reactants and products no longer change, although the forward and reverse reactions continue to occur.
rates; concentrations
Substance to the left of the arrow
reactant
The starting material in a chemical reaction is called a(n) ____, whereas a substance formed in a chemical reaction is called a(n) _____.
reactant; product
H of COOH group
readily ionizable
A chemical reaction where reactants combine to form products, and products can recombine to form the starting reactants is considered a(n) ____ reaction.
reversible
A precipitation reaction occurs when two or more water-____ salts react in solution to produce a(n) _____ precipitate.
soluble; insoluble
If a fair amount of solute visibly dissolves when added to water, the soluble is qualitatively described as being ___ in water. A solute that does not visibly dissolve is considered _____.
soluble; insoluble
A solution is a homogeneous mixture, composed of one more ____ dissolved in ____.
solutes; solvent
Place the steps necessary to balance a chemical equation correctly in order, starting with the final step at the top of the list
1. Place reactants on the left of the reactant arrow, and products on the right 2. Balanced the atoms 3. Adjust the coefficient such that they are the smallest whole-number coefficient 4. Do a final check to make sure that the equation is balanced
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 steps at the top of the list
1. Write a balanced equation for the reaction 2. Convert the given mass into moles using molar mass 3. Convert the moles of the second substance to mass using its molar mass
In a reversible reaction ____. (Select all that apply).
Both forward and reverse reactions can occur together The reaction can proceed from reactants to products, or from products to reactants
In a reversible reaction ____. (Selects all that apply).
Both forward and reverse reactions can occur together The reaction can proceed from reactants to products, or from products to reactants
Which of the following options correctly contrast strong and weak acids in terms of electrolyte behavior? Select all that apply.
Both strong and weak acids are electrolytes. A solution of a weak acid always contains some unionized acid molecules. All molecules of a strong acid will ionize in aqueous solution.
Liquid bromine (Br2) reacts with ethylene (C2H4) to form dibromoethane (C2H4Br2) according to the balanced equation shown below. If 25.0g of Br2 is allowed to react with 5.00 g of C2H4, what is the maximum amount of product that can be made? Which reactant is limiting? C2H4 + Br2 = C2H4Br2
Br2 is limiting 29.3 g of C2H4Br2 Reason: 0.156 x C2H4Br2 x 187.9 g C2H4Br2/ 1 mol C2H4BR2 = 29.3 g C2H4Br2
When methane is heated with water vapor, the gases carbon monoxide and hydrogen are formed. Which of the following is the correct balanced equation for this process.
CH4(g) + H2O (g) = CO(g) + 3H2(g)
Which of the following statements correctly interpret the balance chemical equation CH4(g)+H2O(g)+CO(g)+3H2(g)? Select all that apply
CO is a product in this equation The entire reaction occurs in the gaseous state
Which of the following ions typically form water-insoluble salts, except when partnered with a Group 1A cation or NH4+?
CO3^2- OH^- PO4^3-
Select all the compounds that are correctly paired with their solubility in water at 25°C.
CaSO4, insoluble (NH4)2S, soluble
Which of the following statements correctly describe the method for finding the limiting reactant in a chemical reaction?
Determine which of reactant will produce the smallest amount of product
Strong electrolyte
Dissociates or ionizes 100% in water and conducts an electric current in aqueous solution
Weak electrolyte
Dissociates or ionizes less than 100% in water, and conducts a limited amount of electric current in aqueous solution
An electric current is a flow of charge through a medium, and can be carried by the movement of ___. (Select all that apply).
Electrons Ions
TRUE OR FALSE: In order to balance the reaction of hydrogen gas (H2) with oxygen gas (O2) to form liquid water (H2O), a student adds a subscript of 2 after the oxygen in H2O. This is an acceptance method of balancing the above equation
FALSE
B2 reacts with AB to form AB2 according to the balanced equation B2 + 2AB → 2AB2. If 1.5 moles of B2 are reacted with 1.5 moles of AB, the maximum amount of AB2 that can form is equal to _____ moles.
1.5 Reasons: The reaction requires 2 moles of AB for every 1 mole of B2, so AB is the limiting reagent. Each mole of AB produces 1 mole of AB2.
The balanced equation 2S(s) + 3O2 (g) = 2SO3 (g) is given. The number of moles of SO3 that will form from the complete reaction of 1.5 mol of O2 is given by _____.
1.5 mol O2 x 2mol SO3/ 3 mol O2
Given the balanced equation shown, which of the conversion factors below would be necessary to convert mass of N2 (g) consumed to mass of NH3 (g) produced? Select all that apply N2(g) +3H2(g) = 2NH3(g)
17.03g NH3/ 1 mol NH3 2mol NH3/ 1 mol N2 1mol N2/ 28.02 g N2
Given the balanced equation 2Al (s) + 3Cl2(g) = 2AlCl3(s) select all the conversion factors that correctly represent the molar relationships in this equation
2 mol Al/ 3mol Cl2 2 mol AlCl3/ 3 mol Cl2
The balanced equation 4Al (s) +3O2 (g) = 2Al2O3 (s) is given. The number of moles of Al that will be consumed in order to form 2.5 mol of Al2O3 is given by ____.
2.5 mol Al2O3 x 4mol Al/ 2mol Al2O3
Given the balanced equation 2AgNO3(aq) +Zn(s) = 2Ag(s) + Zn(NO3)2 (aq), determine the MOLES of Zn required and the MASS of Ag from the complete reaction of 9.02 g of AgNO3.
2.65 x 10^-2 mol Zn are required 5.73 g of Ag are formed
