Cumulative Exam Answers

Which is a feature of a single replacement reaction?

A teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. Which would be the best demonstration that she could use?

A single atom of an element has 21 neutrons, 20 electrons, and 20 protons. Which element is it?

Which of the following best describes a pair of elements that will form an ionic bond?

Consider the balanced equation below.N2H4 + 2H2O2 N2 + 4H2OWhat are the mole ratios of hydrazine (N2H4) to hydrogen peroxide (H2O2) and hydrazine to water?

A mixture of three noble gases has a total pressure of 1.25 atm. The individual pressures exerted by neon and argon are 0.68 atm and 0.35 atm, respectively. What is the partial pressure of the third gas, helium?Use .

The diagram below shows that the periodic table is divided into different blocks.Elements that have complete valence electron shells are mostly found in the

Consider the half reactions below for a chemical reaction.What is the overall equation for this chemical reaction?

The chemical equation below shows the combustion of methane (CH4).CH4 + 2O2 CO2 + 2H2OThe molar mass of oxygen gas (O2) is 32.00 g/mol. The molar mass of carbon dioxide (CO2) is 44.01 g/mol. What mass of CO2, in grams, will form when 8.94 g O2 completely react?

Consider the reaction below.2C6H14 + 19O2 12CO2 + 14H2OHow many moles of hexane (C6H14) must burn to form 18.4 mol of carbon dioxide?

The expression below was formed by combining different gas laws. Which law was used to determine the relationship between the volume and the number of moles in this equation?

Which element is likely to have a high thermal conductivity?

Which diagram shows electrons violating the Pauli exclusion principle?

A gas in a rigid container at 25°C has a pressure of 0.96 atm. A change in temperature causes the pressure to increase to 1.25 atm. What is the new temperature of the gas?Use .

In the molecules below, areas that have a partial negative charge are pink and areas that have a partial positive charge are blue. The attractive force between these two molecules has most likely been produced by

Based on the activity series provided, which reactants will form products?F > Cl > Br > I

Which statement is true about crystal lattice energy?

When chemists convert ethene (C2H2) to ethanol (CH3CH2OH), they have a mixture of the two gaseous substances. Why do chemists then lower the temperature of the mixture?

What is the element Ar classified as in the periodic table?

In which orbitals would the valence electrons for carbon (C) be placed?

Which task most likely involves a calculation that uses moles?

Which element would most likely have chemical properties similar to that of fluorine (F)?

The boiling points of different substances are given in the table below.SubstanceBoiling point (°C)Acetic acid118.1Benzene80.2Chloroform61.2Water100.0Which substance most likely has the strongest intermolecular forces?

Consider the diagram.Which postulate of the kinetic-molecular theory best describes the event in the diagram?

The following reaction occurs in a car’s catalytic converter.2NO(g) + 2CO(g) N2(g) + 2CO2(g) Which answer best describes the reducing and oxidizing processes in this reaction?

The volume of a fixed amount of gas is doubled, and the absolute temperature is doubled. According to the ideal gas law, how has the pressure of the gas changed?

Two students are given two different size blocks of the same substance and are instructed to determine the properties of the substance. Which statement describes a property that will be the same for both students?

Which of the following is an oxidation-reduction reaction?

The following half-reaction method is used to balance oxidation-reduction equations.(1) Determine which atoms change oxidation state from reactant to product in the reaction.(2) Identify and write half reactions (oxidation and reduction).(3) Return to the original chemical equation to balance it.(a) Insert the coefficients from the half reactions first.(b) Inspect the number of each atom on each side for all elements.Which important step is missing from this procedure?

Which best describes a compound such as magnesium oxide?

Which is the formula mass of Na2SO4?

Which compound contains both sigma and pi bonds?

Which statement explains how the bands in the crystal of a metal are like atomic orbitals?

What is the percent by mass of magnesium sulfate in MgSO4 · 7H2O?Use .

Which can be categorized as a use of plasma in technology?

The table below gives the numbers of protons, electrons, and neutrons in four atoms.AtomNumber of protonsNumber of electronsNumber of neutrons1393952240405033939544404051Based on the information that is given, which atom in the table has the highest mass?

Which statement best compares the energy involved in melting with the energy involved in boiling for a given liquid?

An element has five valence electrons available for bonding. This element is most likely which of the following?

Consider the balanced equation. PCl3 + 3H2O H3PO3 + 3HCl What is the percent yield of HCl if 42.0 g of HCl are produced from the reaction of 62.0 g of PCl3?Use .

The chemical equation below shows the burning of magnesium (Mg) with oxygen (O2) to form magnesium oxide (MgO).2Mg + O2 2MgOThe molar mass of O2 is 32.0 g/mol. What mass, in grams, of O2 is required to react completely with 4.00 mol of Mg?

Consider the redox reaction below.Which statement correctly describes a half-reaction that is taking place?

Which statement best explains why different gases effuse at different rates?

The table describes solids and plasmas.Which statement can be placed in the blank cell to make the information in the table accurate?

A sample of ammonia reacts with oxygen as shown.4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g)What is the limiting reactant if 4.0 g of NH3 react with 8.0 g of oxygen?

What is the true ratio of atoms in a molecule or formula unit called?

Which is true of transition metals when moving from left to right on the periodic table?

An electron in a hydrogen atom moves from level 1 to level 4. The electron then drops from level 4 to level 2. Which statement describes the most likely result?

The diagrams below represent the four states of matter. Diagram 1 Diagram 2 Diagram 3 Diagram 4Which diagram represents a gas that has been ionized?

The properties of two elements are listed below.ElementAtomic radius(pm)Ionic radius(pm)First ionization energy(kJ/mol)Electron affinity(kJ/mol)ElectronegativityBr1141951140–3253.0K243152.2418.8–48.40.82Which prediction is supported by the information in the table?

Consider the heating curve.In which region are most particles moving the fastest?

Kumar is producing the photoelectric effect by using red light. He wants to increase the energy of emitted electrons. Based on the research of Albert Einstein, what is the best way for him to do this?

When a drawing of a circle made in the center of a piece of paper with a black marker gets wet, the marker bleeds, and as the water moves through the paper the ink separates into several colors. What method of separation does this describe?