Chemistry Final First Semester

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? 1 2 3 4

2

Which statement describes a limitation of the kinetic-molecular theory for a gas? The theory assumes that particles do not experience intermolecular forces. The theory states that pressure is inversely proportional to volume. The theory assumes that particles are in random and continuous motion. The theory states that pressure increases with temperature.

A

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

C

Which shows the electron configuration for zinc (Zn)? [Kr]5s24d10 [Kr]5s24d6 [Ar]4s23d9 [Ar]4s23d10

D

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

B

Which is most likely true about electronegativity? It tends to be the same across a period. It tends to be the same down a group. It tends to increase across a period. It tends to increase down a group.

C

Which physical method can separate a mixture of steel ball bearings and marbles? boiling evaporation filtration sorting

D

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

A

The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have? 24 28 76 80

B

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? 60.8 81.1 122 182

D

If a substance reacts with oxygen, the chemical reaction is most likely a combustion reaction. decomposition reaction. single replacement reaction. double replacement reaction.

A

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? 1.00 18.0 36.0 324

A

Which best describes the trends in electronegativity on the periodic table? Electronegativity increases up and to the right. Electronegativity increases down and to the left. Electronegativity decreases up and to the left. Electronegativity decreases down and to the right.

A

Which property would xenon most likely have? It is stable. It is a solid. It is flammable. It is silver in color.

A

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

B

The diagrams show the particles of a substance.Which statement best describes the process that the diagrams show? A solid loses kinetic energy to become a liquid and then becomes a gas. A solid gains kinetic energy to become a liquid and then becomes a gas. A gas loses kinetic energy to become a liquid and then becomes a solid. A gas gains kinetic energy to become a liquid and then becomes a solid.

B

What is the electron configuration for helium (He)? 1s1 1s2 1s22s1 1s22s2

B

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

B

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

B

Which sequence represents the relationship between pressure and volume of an ideal gas as explained by the kinetic-molecular theory? more gas particles --> more collisions --> higher pressure smaller volume --> crowded particles --> less collisions --> lower pressure smaller volume --> crowded particles --> more collisions --> higher pressure more gas particles --> more kinetic energy --> more volume --> higher pressure

C

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

C

An atom of an element is shown by the model.How is this model useful? It shows how electrons are distributed in the shells of an iron atom. It shows how electrons are distributed in the shells of a cobalt atom. It shows how orbitals are distributed in the shells of an iron atom. It shows how orbitals are distributed in the shells of a cobalt atom.

A

An electron in a hydrogen atom moves from level 3 to level 1. In a second hydrogen atom, an electron drops from level 2 to level 1. Which statement describes the most likely result? The first atom emits light with more energy. The second atom emits light with more energy. The first and second atoms absorb energy without emitting light. The first and second atoms emit light with the same amount of energy.

A

Which describes a step in the process of forming an ionic bond? A metal atom loses electrons and becomes a positive ion. A metal atom gains electrons and becomes a negative ion. A nonmetal atom loses electrons and becomes a negative ion. A nonmetal atom gains electrons and becomes a positive ion.

A

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

A

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

A

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

B

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

C

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

C

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

C

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

C

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

C

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

C

Which is a correct comparison between the modern quantum model and John Dalton's model of the atom? The modern model is not as widely accepted by scientists as Dalton's model. The modern model states that atoms of all elements are identical, whereas Dalton's model does not. The modern model recognizes particles in the atom, whereas Dalton's model does not. The modern model does not explain emission spectra, whereas Dalton's model does.

C

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

C

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

C

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

D

An unbalanced chemical equation for the reaction of boron fluoride with lithium sulfite is shown below. BF3 + Li2SO3 --> B2(SO3)3 + LiF What is the coefficient of lithium fluoride in the balanced chemical reaction? 1 3 4 6

D

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? They have exactly the same mass. They have different numbers of particles. They have the same number of atoms. They have different masses.

D

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? 9.01 18.01 36.03 72.06

D