exam 2 chem pt.2

Which of the following substances are the products in this chemical reaction? Select all that apply. CH3CH2OH + 3 O2 → 2 CO2 + 3 H2O a) O2 b) CH3CH2OH c) CO2 d) H2O

CO2, H2O

Select all that apply A physical change may involve _____ (Check all that apply.) a) a change in shape. b) a change in phase. c) a change in color. d) a change in volume. e) a change in the substances present

a) a change in shape b) a change in phase c) a change in volume

Select all that apply Which of the following are included in a complete balanced chemical equation? (Select all that apply.) a) coefficients b) reactants c) reaction arrow d) products e) reaction time f) phases

a) coefficients b) reactants c) reaction arrow d) products f) phases

Select all that apply Which of the following statements correctly describe oxidizing agents and reducing agents? Select all that apply. a) An oxidizing agent gains electrons. b) Every redox reaction has a reducing agent and an oxidizing agent. c) A reducing agent gains electrons. d) An oxidizing agent is reduced. e) A reducing agent causes an element to be oxidized.

a, b, d

Select all of the statements below that correctly interpret the following balanced equation: 4 HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2 H2O (l) + Cl2 (g) a) HCl is a reactant in this equation. b) The MnO2 used in this reaction is a solution. c) The MnCl2 produced is dissolved in water. d) Water is both a solvent and a product in this reaction. e) 4.00 g of HCl reacts with 1.00 g of MnO2.

a, c, d

Select all of the statements below that correctly interpret the following balanced equation: 4 HCl (aq) + MnO2 (s) → MnCl2 (aq) + 2 H2O (l) + Cl2 (g) a) 4.00 g of HCl reacts with 1.00 g of MnO2. b) The MnCl2 produced is dissolved in water. c) Water is both a solvent and a product in this reaction. d) The MnO2 used in this reaction is a solution. e) HCl is a reactant in this equation.

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

Which of the following describe a physical change? (Select all that apply.) a) The burning of a candle b) The melting of a chocolate bar The cooking of an egg c) Dissolving sugar in a cup of hot tea

b) The melting of a chocolate bar c) Dissolving sugar in a cup of hot tea

In a balanced chemical equation, which of the following must be the same on both sides of the equation? Select all that apply. a) Number of molecules b) Number of atoms of each element c) Potential energy d) Elements represented e) Phase labels

b) number of atoms of each element d) elements represented

Select all of the statements below that correctly interpret the following balanced equation: 4 C (s) + S8 (s) → 4 CS2 (l) a) 4 grams of carbon react with 1 gram of S8 to form 4 grams of CS2. b) 4 moles of carbon react with 1 mole of S8 to form 4 moles of CS2. c) Carbon and S8 are reactants and CS2 is the product. d) 4 atoms of carbon react with 1 molecule of S8 to form 4 molecules of CS2.

b, c, d

Which of the following should you do when balancing a chemical equation? (Select all that apply.) a) Move a substance from one side of the chemical equation to the other when necessary. b) Change subscripts in chemical formulas to balance the equation when necessary. c) Check your solution to verify that the same number of each type of atom is present on both sides of the reaction. d) Balance the equation with coefficients one element at a time.

c) Check your solution to verify that the same number of each type of atom is present on both sides of the reaction. d) Balance the equation with coefficients one element at a time.

As a result of the law of conservation of mass, a balanced chemical equation must a) be balanced by having the same number of product substances as reactant substances. b) contain a gas on both sides of the chemical equation. c) have the same number of atoms of each type on both sides of the equation

c) have the same number of atoms of each type on both sides of the equation

Correctly order the steps necessary to balance a chemical equation. a) Adjust the the coefficients such that the smallest whole-number coefficients are used. b) Balance the atoms of each element in turn, by adding coefficients before the chemical formulas of reactants and products c) Write a skeleton equation d) Do a final check to make sure the equation is balanced

c, b, a, d

The conversion of potassium chlorate to potassium chloride and oxygen is an example of a __________ change.

chemical

Which of the following actions are permitted in balancing a chemical equation? a) Inserting a coefficient between two elements in the formula of a compound b) Adding reactants or products c) Altering the formulas of reactants or products d) Inserting coefficients before the formulas of reactants and products e) Multiplying all coefficients by a common factor

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

The law of conservation of matter states that a) substances cannot be created or destroyed in a chemical reaction. b) the number of reactants is the same as the number of products. c) the number of bonds created is the same as the number of bonds broken in a chemical reaction. d) atoms cannot be created or destroyed in a chemical reaction.

d) atoms cannot be created or destroyed in a chemical reaction

A chemical change must involve ______ a) a change in phase. b) only the breaking of chemical bonds. c) only the forming of chemical bonds. d) the formation of new substances.

d) the formation of new substances

True or false: Chemical equations can be balanced by adding coefficients in front of chemical formulas and by changing the subscripts in a chemical formula.

false

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 redox reactions, cations tend to _____________ electrons; anions tend to _____________ electrons; metals tend to ____________ electrons; and nonmetals tend to ___________ electrons.

gain; lose; lose; gain

The boiling of water is an example of a _____ change. a) physical b) chemical

physical

The new substances that are formed in a chemical reaction are called _____. reactants products coefficients

products

In chemical reaction, the starting materials are called ____________

reactants

A chemical change must involve ______ a) only the forming of chemical bonds. b) only the breaking of chemical bonds. c) the formation of new substances. d) a change in phase.

the formation of new substances

Reduction is ______ the gain of protons by an atom. the loss of electrons from an atom. the loss of protons from an atom. the gain of electrons by an atom.

the gain of electrons by an atom.

True or False: A chemical change may involve physical changes

true

In the following reaction, which is commonly found in alkaline batteries, Zn + 2 MnO2 + 2 H2O → Zn(OH)2 + 2 MnO(OH), the formula of the oxidizing agent is ___________ reduction , Incorrect Unavailable and the formula of the reducing agent is ____________

MnO2; Zn

True or false: The same substance may appear as both a reactant and a product in a chemical reaction.

False