Chemistry midterm review

includes the coefficients that are needed for balancing the equation.

A chemical equation can be used to solve stoichiometry problems provided that it indicates only the forward reaction and not the reverse. A- indicates only the forward reaction and not the reverse. B- indicates that reactants are in the gas phase and are not solids or liquids. C- includes the coefficients that are needed for balancing the equation. D- includes the state of matter after each substance.

0.36 atm

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia? A- 0.27 atm B- 0.36 atm C- 0.54 atm D- 0.90 atm

0.75 atm

A tire at 21°C has a pressure of 0.82 atm. Its temperature decreases to -3.5°C. If there is no volume change in the tire, what is the pressure after the temperature change? A- 0.75 atm B- 0.89 atm C- 1.1 atm D- 1.3 atm

The volume stays the same, but the shape changes to fit the new container.

According to the kinetic-molecular theory, what happens to a liquid when it is transferred from one container to another? A- The volume and the shape stay the same. B- The volume increases to fill the new container, but the shape stays the same. C- The volume stays the same, but the shape changes to fit the new container. D- The volume and the shape change to fill the new container.

It has six valence electrons available for bonding

Based on its location in the periodic table, what can most likely be predicted about sulfur? A- It has four valence electrons available for bonding. B- It has four nonbonding electrons. C- It has six valence electrons available for bonding. D- It has six nonbonding electrons.

1:1

Consider the balanced equation below. PCl3 + Cl2 --> PCl5 What is the mole ratio of PCl3 to PCl5? A- 1:1 B- 2:1 C- 3:5 D- 5:3

1:1

Consider the equation below. Zn + H2SO4 ZnSO4 + H2 The mole ratio of zinc to zinc sulfate is A- 1:1. B- 1:2. C- 2:1. D- 3:1.

160 g

Consider the equation for the formation of water. 2H2 + O2 2H2O What is the theoretical yield of H2O if 130 g of H2O is produced from 18 g of H2 and an excess of O2? A- 18 g B- 81 g C- 130 g D- 160 g

8.25

Consider the reaction below. 2Al2O3 4Al + 3O2 How many moles of oxygen are produced if 11.0 mol of Al are produced? A- 8.25 mol B- 11.0 mol C- 14.7 mol D- 16.5 mol

They have different masses

Consider the substances below. • 1 mol of beryllium • 1 mol of salt • 1 mol of water • 1 mol of hydrogen Which statement is true about these substances? A- They have exactly the same mass. B- They have different numbers of particles. C- They have the same number of atoms. D- They have different masses.

C6H12O6

If a compound has a molar mass of 180 g/mol and its empirical formula is CH2O, what is its molecular formula? A- CH2O B- C2H4O2 C- C6H12O6 D- C12H22O11

14.2

Juana performs the calculation below. 6.05 + 3.156 + 5.0 How should she report the answer using the correct number of significant figures? A- 14.206 B- 14.21 C- 14.2 D- 14

two

Mary performs this calculation. (3.0)(2.0) How many significant figures should her answer have? A- one B- two C- four D- six

65.2%

Nitrogen dioxide, a major air pollutant, can be produced by the combustion of nitrogen oxide as shown. 2NO + O2 2NO2 In a plant, 1,500 kg of nitrogen oxide is consumed per day to produce 1,500 kg of nitrogen dioxide per day. What is the percent yield? A- 21.7% B- 32.6% C- 43.5% D- 65.2%

15.0 mol

The following balanced equation shows the formation of sulfur dioxide. S + O2 SO2 How many moles of sulfur are needed to produce 15.0 mol of sulfur dioxide? A- 7.50 mol B- 10.5 mol C- 15.0 mol D- 30.0 mol

pressure

The ideal gas constant, R has several different values that could be used. Which quantity causes these differences? A- pressure B- temperature C- volume D- moles

1.00

The molar mass of water (H2O) is 18.0 g/mol. A sample of water has a mass of 18.0 g. How many moles of water are contained in this sample? A- 1.00 B- 18.0 C- 36.0 D- 324

NaNO3.

The two products that are formed when a solution of HNO3 and a solution of NaOH react are water and A- NaNO2. B- NaNO3. C- NaHNO. D- NaHNO3.

It will double.

The volume of a gas decreases to half of its original volume, but the gas maintains the same number of moles and temperature. According to the ideal gas law, what will most likely happen to the pressure? A- It will double. B- It will decrease. C- It will increase slightly. D- It will remain the same.

2

This formula equation is unbalanced. BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation? A- 1 B- 2 C- 3 D- 4

3.33 L

What is the volume of 0.200 mol of an ideal gas at 200. kPa and 400. K? A- 0.83 L B- 3.33 L C- 5.60 L D- 20.8 L

He identified triads of elements that had similar properties

What was Johann Dobereiner's contribution to the development of the periodic table? A- He arranged the elements according to increasing atomic mass. B- He arranged the elements according to increasing atomic number. C- He identified triads of elements that had similar properties. D- He organized elements into four groups based on their properties.

v=n/P

Which proportionality shows the result of combining Avogadro's law with Boyle's law? A- v=1/nP B- v=n/P C- v=P/n D- v=nP

light with a high enough frequency

Which statement best describes the light that will cause emission of electrons from a given metal through the photoelectric effect? A- light with a low enough intensity B- light with a high enough frequency C- light with a high enough intensity D- light with a low enough frequency

it allows chemists to deal with a large number of atoms

Which statement best explains the purpose of using a mole in the measurement of matter? A- It is commonly used as another unit of mass. B- It allows chemists to deal with a large number of atoms. C- It is used only for studying the properties of gases. D- It explains that substances with the same moles have the same mass.

synthesis

Which type of reaction is Mg + S → MgS? A- polymerization B- synthesis C- replacement D- decomposition

decomposition

A chemical reaction that has the general formula of AB → A + B is best classified as a _____ reaction.

a pure substance and an element

A piece of sodium metal can be described as A- a pure substance and a compound. B- an impure substance that is reactive. C- an impure substance that is unreactive. D- a pure substance and an element.

sulfur

A plate of the steel hull of a ship develops a large crack when the ship strikes a reef. Analysis of the steel's composition shows higher-than-normal levels of an element that could explain why the plate cracked instead of bending. Which element is most likely suspected? A- iron B- sulfur C- chromium D- nickel

C6H5OH (aq)

An acid is a substance that increases the concentration of H3O+ ions in solution. Look at the reaction below of phenol (C6H5OH) with water: C6H5OH + H2O --> C6H5O + H3O Which reactant acts as an acid by contributing a H+ ion to create H3O+ in the chemical equation? A- C6H5OH(aq) B- H2O(l) C- C6H5O-(aq) D- H3O+(aq)

83.9%

In a chemical reaction, substance R reacts with compound XY to produce 47.0 g of compound RX. If the theoretical yield of RX is 56.0 g, what is its percent yield? A- 9.00% B- 16.1% C- 83.9% D- 119%

NaCl

The balanced equation shows how sodium chloride reacts with silver nitrate to form sodium nitrate and silver chloride. NaCl + AgNO3 NaNO3 + AgCl If 4.00 g of NaCl reacts with 10.00 g of AgNO3, what is the excess reactant? A- AgCl B- NaCl C- AgNO3 D- NaNO3

potassium hydroxide

What name should be used for the ionic compound KOH? A- potassium oxide B- potassium oxygen hydride C- potassium hydroxide D- potassium hydrogen oxide

sorting

Which physical method can separate a mixture of steel ball bearings and marbles? A- boiling B- evaporation C- filtration D- sorting

to add tartness

Why is citric acid added to food? A- to add color B- to add tartness C- to add bitterness D- to add sweetness

C6H5OH(aq)

An acid is a substance that increases the concentration of H3O+ ions in solution. Look at the reaction below of phenol (C6H5OH) with water: C6H5OH(aq)+H2O(l)--> C6H5O-(aq)+ H3O+(aq) Which reactant acts as an acid by contributing a H+ ion to create H3O+ in the chemical equation? A- C6H5OH(aq) B- H2O(l) C- C6H5O-(aq) D- H3O+(aq)

is an acid

An unknown substance turns methyl orange solution red. This shows that the substance A- is a base. B- is water. C- is an acid. D- is an alkaloid.

Sodium + water --> sodium hydroxide + hydrogen

Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction? A- sodium hydroxide + water --> sodium + hydrogen B- sodium + water --> sodium hydroxide + hydrogen C- sodium + hydrogen --> sodium hydroxide + water D- sodium + sodium hydroxide --> water + hydrogen

182

The chemical equation below shows the formation of aluminum oxide (Al2O3) from aluminum (Al) and oxygen (O2). 4Al + 3O2 2Al2O3 The molar mass of O2 is 32.0 g/mol. What mass, in grams, of O2 must react to form 3.80 mol of Al2O3? A- 60.8 B- 81.1 C- 122 D- 182

it reacts with sodium metal

Which statement describes a chemical property of water? A- It reacts with sodium metal. B- It has a melting point of 0°C. C- It has a density of about 1 g/mL. D- It is clear and colorless.

lithium + oxygen --> lithium oxide

Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium? A- oxygen + lithium oxide --> lithium B- lithium + oxygen --> lithium oxide C- oxygen + lithium --> lithium + oxide D- lithium oxide --> lithium + oxygen

forms of the same element that differ in the number of neutrons in each atom

How are isotopes defined? A- forms of different elements that have the same number of neutrons in each atom B- forms of different elements that have the same number of protons in each atom C- forms of the same element that differ in the number of neutrons in each atom D- forms of the same element that differ in the number of protons in each atom

72.06

The chemical equation below shows the decomposition of ammonium nitrate (NH4NO3). NH4NO3 N2O + 2H2O A chemist who is performing this reaction starts with 160.1 g of NH4NO3. The molar mass of NH4NO3 is 80.03 g/mol; the molar mass of water (H2O) is 18.01 g/mol. What mass, in grams, of H2O is produced? A- 9.01 B- 18.01 C- 36.03 D- 72.06

Yes, if each sample contains 6.02 x 1023 atoms.

The mass and volume of each sample differ from the mass and volume of the other samples. Is it possible for each sample to contain 1 mol of each substance? A- No, because they have different masses. B- No, because they have different volumes. C- Yes, if each sample contains 6.02 x 1023 atoms. D- Yes, if each sample contains 2 amu.

The glass opposite of the negative electrode started to glow.

What did J. J. Thomson observe when he applied electric voltage to a cathode ray tube in his famous experiment? A- The stream of cathode ray particles was moving very slowly. B- The glass opposite of the negative electrode started to glow. C- The electric voltage had little effect on the stream of particles. D- The tube contained two pieces of metal that served as electrodes.

The valence electrons move between atoms in shared orbitals

What does it mean that valence electrons in a metal are delocalized? A- The valence electrons move between atoms in shared orbitals. B- The valence electrons move from outer orbitals to inner orbitals of each atom. C- The valence electrons move from inner orbitals to outer orbitals of each atom. D- The valence electrons move out of the orbitals and go into the air.

MgCl2

What else is produced during the replacement reaction of magnesium and hydrochloric acid? Mg + 2HCl H2 + ________ A- MgCl2 B- Mg2Cl2 C- Mg2Cl D- MgCl

Zn(NO3)2 + Cu

What is produced during the replacement reaction of Cu(NO3)2 and Zn? A- ZnNO3 + Cu B- Zn + Cu(NO3)2 C- ZnCu + 2NO3 D- Zn(NO3)2 + Cu

CuSO4

What is the chemical formula for copper(II) sulfate? A- CuSO4 B- Cu2SO4 C- CuS D- Cu2S

2.50 10-5 m

What is the correct way to write 0.0000250 m in scientific notation? A- 2.50 10-5 m B- 2.5 10-5 m C- 2.50 10-4 m D- 2.5 10-4 m

CH2

What is the empirical formula for propene (C3H6)? A- C2H4 B- C4H8 C- C3H6 D- CH2

The activation energy needs to be overcome in the reaction.

What is the main reason that it takes 2 to 3 minutes for the reaction to occur between sucrose and sulfuric acid in the dehydration of sucrose? A- The activation energy needs to be overcome in the reaction. B- The activation energy must be removed from the intermediates. C- The sulfuric acid has to be consumed before the reaction takes place. D- The sucrose molecules must rearrange to become the catalyst.

55.92%

What is the percent by mass of water in Na2SO4 • 10H2O? A- 5.59% B- 11.26% C- 44.08% D- 55.92%

2:3

What is the ratio of Fe ions to O ions in a neutral compound? A- 1:2 B- 2:1 C- 2:3 D- 3:2

A mole contains Avogadro's number of particles of a substance.

What is the relationship between a mole and Avogadro's number? A- A mole is the mass of Avogadro's number of particles of a substance. B- A mole is the amount of a compound that has Avogadro's number of carbon-12 atoms in it. C- A mole contains Avogadro's number of particles of a substance. D- A mole is the amount of any substance that has the same mass as Avogadro's number of carbon-12 atoms.

roman numerals

What should the IUPAC name for a binary covalent compound lack? A- prefixes B- Roman numerals C- an -ide ending D- the name of a nonmetal

a dense substance that is hard and incompressible

Which best characterizes a crystal? A- a number of high speed particles moving randomly B- a dense substance that is hard and incompressible C- a high-energy state of matter made up of a swirling, ionized gas D- a loose association of particles moving past one another

the minimum energy that a set of reactants must attain before reaction can occur

Which definition describes activation energy? A- the speed at which reactants form products in a chemical reaction B- the short-lived, high-energy intermediate between reactants and products C- the diagram showing a change in energy between reactants and products D- the minimum energy that a set of reactants must attain before reaction can occur

Ca

Which element would most likely have chemical properties similar to that of magnesium (Mg)? A- Ar B- Ca C- F D- Ni

An atom is a small particle that cannot be broken down.

Which is a component of John Dalton's atomic theory? A- The ratio of atoms in a compound can vary. B- The atoms of a single element differ. C- An atom is a small particle that cannot be broken down. D- Atoms of different elements can be identical.

Gas particles have a small volume relative to the spaces between them.

Which is a postulate of the kinetic-molecular theory? A- Gas particles have a small volume relative to the spaces between them. B- Gas particles have a large volume relative to the spaces between them. C- Gas particles are very small in size and always move slowly. D- Gas particles are very large in size and always move slowly.

they have a low boiling point

Which is a property of covalent compounds? A- They ionize in solution. B- They tend to be very hard. C- They have a low boiling point. D- They have a high melting point.

Particles move independently of one another and are widely spaced.

Which is an aspect of the kinetic-molecular theory and can be used to explain the compressibility of plasmas? A- Particles move independently of one another and are widely spaced. B- Particle kinetic energy increases with increasing temperature. C- Particles exert no attractive or repulsive force on one another. D- Particles always move even when they have fixed positions.

Boyle's law

Which law is described by saying that when the pressure of a gas in a sealed container is cut in half, the gas will double in volume at a steady temperature? A- Boyle's law B- Charles's law C- Dalton's law D- Gay-Lussac's law

the number of electrons that are involved in the bonding of the molecule

Which of the following do Lewis structures help us understand? A- the exact structure of a molecule B- the number of electrons that are involved in the bonding of the molecule C- the total number of electrons in a molecule D- how electrons attract other electrons in a molecule

It cannot be physically broken down into different types of atoms.

Which of the following observations would indicate that a material is a pure substance? A- It does not dissolve in water. B- It changes color after heating. C- It cannot be physically broken down into different types of atoms. D- It can be physically broken down into different types of molecules.

It is stable

Which property would xenon most likely have? A- It is stable. B- It is a solid. C- It is flammable. D- It is silver in color.

moles

Which quantity is held constant when working with Boyle's, Charles's, and Gay-Lussac's laws? A- volume B- moles C- pressure D- temperature

because they have delocalized electrons

Which reason best explains why metals are malleable? A- because they have delocalized electrons B- because they have localized electrons C- because they have ionic bonds D- because they have rigid bonds

NH4NO3

Which salt is produced when NH4OH reacts with HNO3? A- KNO2 B- NaNO3 C- NH4NO3 D- NH4NO2

Joseph Proust

Which scientist's law about the ratios of masses of elements in a compound did John Dalton's work on the atomic structure help to explain? A- Democritus B- J. J. Thomson C- Ernest Rutherford D- Joseph Proust

The melting point is higher for the substance that has stronger intermolecular forces.

Which statement best compares the melting point of butane (C4H10) with that of octane (C8H18)? A- The melting points of both substances are identical. B- The melting point is lower for the substance that has stronger attractive forces. C- The melting point is higher for the substance that has stronger intermolecular forces. D- The melting point is not dependent on intermolecular forces.

Use enough cations and anions so that the total charge is zero.

Which statement best describes how to predict the formula of a stable ionic compound? A- Use the same number of cations as anions so that the compound is neutral. B- Use more cations than anions so that the compound is positively charged. C- Use enough cations and anions so that the total charge is zero. D- Use fewer cations than anions so that the compound is negatively charged.

solutions of salt and water conduct electricity

Which statement best describes salts? A- Salts form from hydrogen ions and hydroxide ions in neutralization reactions. B- Most salts do not dissociate when dissolved in water. C- Most salts form solutions that are neutral. D- Solutions of salt and water conduct electricity.

changes with the amount of a substance present

Which statement describes an extensive property of matter? A- It changes with the color of a substance. B- It changes when a new substance is formed. C- It changes with the amount of sample that is present. D- It changes with the composition of a substance.

They are made up of two or more pure substances that are not chemically bonded together and appear non-uniform.

Which statement describes heterogeneous mixtures? A- They are made up of two or more pure substances that are not chemically bonded together and appear non-uniform. B- The substances they are composed of can only be separated chemically. C- The substances they are composed of have fixed ratios between their components. D- They are made up of two or more pure substances that are chemically bonded together and appear uniform.

this model is the simplest model

Which statement describes the electron sea model for metallic bonding? A- This model involves electrons held tightly between atoms. B- This model explains all properties of metals. C- This model involves electrons moving among bands of orbitals. D- This model is the simplest model.

they are shared among many atoms

Which statement describes the valence electrons in metallic bonds? A- They are shared equally between two atoms. B- They are shared unequally between two atoms. C- They are shared among many atoms. D- They are transferred from one atom to another.

It is the simplest ratio of atoms in a formula unit

Which statement is true about an empirical formula? A- It is the true ratio of atoms in a formula unit. B- It is the simplest ratio of atoms in a formula unit. C- It represents the true molecular mass of a chemical formula. D- It represents the highest ratio of coefficients in a chemical formula.

ionic bonding

Which type of bonding involves the complete transfer of a valence electron from a less electronegative atom to a more electronegative one? A- ionic bonding B- metallic bonding C- covalent bonding D- hydrogen bonding

Antoine Lavoisier

Who reported four "element" classifications, but included some substances that were combinations of elements rather than true elements in his listing? A- Henry Moseley B- Dmitri Mendeleev C- Antoine Lavoisier D- Johann Dobereiner