Answers CR03101 ChemistryCumulative Exam

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According to the collision theory, which is required for a high number of effective collisions?

a very low amount of force from colliding molecules

a very low amount of kinetic energy from colliding molecules

molecular collisions that have very specific orientations

molecular collisions with energy to overcome activation energy

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A miner develops cancer of the esophagus. Ten years before, he had been exposed to radiation when he worked for a year in a mine. He had also smoked cigarettes for a number of years, but had quit five years ago. Which statement best describes the miner’s condition?

Tests can determine whether the cancer was caused by exposure at the mine or by compounds in cigarette smoke so that a treatment can be determined.

Cancer caused by exposure at the mine would have appeared while he was at the mine, so smoking is the more likely cause.

The cancer is likely the result of natural exposure to radiation in the environment and not related to either the mine or smoking.

It is unlikely that a specific cause can be determined, but the treatment would likely be the same in either case.

Two cups of coffee, one that is at 10°C and one that is at 20°C, are mixed. Which statement about the temperature of the mixture is correct?

There is no kinetic energy transfer so the temperature of the coffee in the warmer cup is the final temperature.

The kinetic theory dictates that the temperature of the coffee in the cooler cup is the final temperature.

Energy is transferred from faster moving molecules to slower moving molecules, and the result is the average of 15°C.

Energy transfer occurs as the molecules collide, and the result is additive; the final temperature is 30°C.

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 energy absorbed in the first move equals the energy released in the second move.

The energy absorbed in the first move is greater than the energy released in the second move.

The energy released in the first move equals the energy absorbed in the second move.

The energy released in the first move is greater than the energy absorbed in the second move.

Consider the following reversible reaction.What is the equilibrium constant expression for the given system?

mc031-2.jpg

K subscript e q equals StartFraction StartBracket upper C upper O subscript 2 EndBracket over StartBracket upper O subscript 2 EndBracket EndFraction.

K subscript e q equals StartFraction StartBracket upper C EndBracket StartBracket upper O subscript 2 EndBracket over StartBracket upper C upper O subscript 2 EndBracket EndFraction.

K subscript e q equals StartFraction StartBracket upper O subscript 2 EndBracket over StartBracket upper C upper O subscript 2 EndBracket EndFraction.

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?

Ladybugs eat aphids on plants. Ajoy counts the number of ladybugs in one square meter of his garden. To estimate the number of ladybugs in the entire garden, Ajoy needs the

dimensions of the garden.

ladybug life span.

number of plants in the garden.

dimensions of a single ladybug.

A radioactive nuclide that is used for geological dating has an atomic number of 19 and mass number 40. Which is the symbol of this nuclide?

Superscript 19 subscript 21 upper K.

Superscript 21 subscript 19 upper K.

Superscript 40 subscript 19 upper K.

Superscript 19 subscript 40 upper K.

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?

Increase the intensity of red light.

Decrease the intensity of red light.

Use a different colored light that has a higher frequency.

Use a different colored light that has a lower frequency.

Which task most likely involves a calculation that uses moles?

measuring a sugar sample on a balance

counting the number of jellybeans in a jar

determining the number of atoms in a jar of liquid

finding the rate of expansion of a gas-filled balloon

Molecules in all organisms are composed in part of radioactive carbon-14. Which statement best explains the presence of carbon-14 in organisms?

The radioactive isotope reacts in the same way as stable isotopes in the nuclear reactions in the body.

The radioactive isotope reacts in the same way as stable isotopes in the chemical reactions in the body.

The radioactive isotope reacts faster than stable isotopes in the nuclear reactions in the body.

The radioactive isotope reacts faster than stable isotopes in the chemical reactions in the body.

A supervisor spends a day inspecting a nuclear plant for potential radiation leaks. She has to move throughout the plant inspecting all the equipment and machinery. She needs to take two different radiation detection devices to help ensure her safety and to find radiation leaks. She needs the results immediately. Which two devices would be the best choices for the task?

Geiger counter and scintillation counter

Geiger counter and cloud chamber

cloud chamber and scintillation counter

film badge and scintillation counter

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

can be crystalline

can be amorphous

are made of charged particles

are made of neutral particles

A sample of an unknown substance has a mass of 0.158 kg. If 2,510.0 J of heat is required to heat the substance from 32.0°C to 61.0°C, what is the specific heat of the substance?Use .

0.171 J/(gi°C)

0.548 J/(gi°C)

15.9 J/(gi°C)

86.6 J/(gi°C)

Which answer choice represents a balanced alpha emission nuclear equation?

Superscript 52 subscript 26 upper F e right arrow superscript 52 subscript 25 upper M n plus superscript o subscript plus 1 e.

Superscript 235 subscript 92 upper U right arrow superscript 239 subscript 94 upper P u s plus superscript 4 subscript 2 upper H e.

Superscript 189 subscript 83 upper Bi right arrow superscript 185 subscript 81 upper T l plus superscript 4 subscript 2 H e.

Superscript 14 subscript 6 upper C right arrow superscript 14 subscript 7 upper N plus superscript 0 subscript negative 1 e.

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

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

s orbital and d orbitals

s orbital only

p orbitals only

s orbital and p orbitals

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

a noble gas

a halogen

a metalloid

a metal

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

taking pictures of solar flares

observing the aurora borealis

making fluorescent lights for houses

making telescopes to observe distant stars

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

The d sublevels are not filled across the period.

The cation radii become larger across the period.

Atomic radii increase slightly and then start to decrease.

Atomic radii decrease slightly and then start to increase.

A sample of propane (C3H8) has a mass of 0.47 g. The sample is burned in a bomb calorimeter that has a mass of 1.350 kg and a specific heat of 5.82 J/(g • °C). How much energy is released by the reaction if the temperature of the calorimeter rises by 2.87°C?Use .

7.85 kJ

10.6 kJ

22.5 kJ

47.9 kJ

Consider the unbalanced equation for the oxidation of aluminum._Al + _O2 _Al2O3Which sequence of coefficients should be placed in the blanks to balance this equation?

2, 3, 1

1, 3, 2

4, 3, 2

3, 2, 3

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

C and H: Hydrogen easily loses electrons, and carbon gains them.

Li and O: Oxygen easily loses electrons, and lithium gains them.

P and Cl: Phosphorus easily loses electrons, and chlorine gains them.

Ca and Br: Calcium easily loses electrons, and bromine gains them.

Which diagram shows electrons violating the Pauli exclusion principle?

A box contains an up arrow.

A box contains an up and a down arrow.

Which is a feature of a single replacement reaction?

Substance XYZ breaks down into X and YZ.

Substance G reacts with compound XY to form GY and X.

Substance X burns rapidly in the presence of oxygen.

Substance QR and GT exchange ions with each other.

Which element is likely to have a high thermal conductivity?

antimony

carbon

chlorine

sodium

There are 6.022 1023 atoms of Hg in 1 mole of Hg. The number of atoms in 4.5 moles of Hg can be found by multiplying 4.5 by 6.022 1023. Which is the number of atoms in 4.5 moles of Hg, correctly written in scientific notation with the correct number of significant figures?

2.7 1024

27 1023

2.71 1024

27.099 1023

The mass of a sample of sodium bicarbonate is 2.1 kilograms (kg). There are 1,000 grams (g) in 1 kg, and 1 109 nanograms (ng) in 1 g. What is the mass of this sample in ng?

2.1 103 ng

2.1 106 ng

2.1 109 ng

2.1 1012 ng

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

At a given pressure, gas particles with smaller masses move faster.

At a given pressure, gas particles with smaller masses move slower.

At a given temperature, gas particles with smaller masses move faster.

At a given temperature, gas particles with smaller masses move slower.

Sodium chloride is made up of clear, colorless crystals. A solution of sodium chloride in water is a good conductor of electricity. Which statement describes sodium chloride?

It is made up of ions that are held together by ionic bonds.

It is made up of atoms that are held together by metallic bonds.

It is made up of atoms that are held together by covalent bonds with equal sharing of electrons.

It is made up of atoms that are held together by covalent bonds with unequal sharing of electrons.

A chemistry journal requires that all new research papers be peer reviewed by other scientists before they are published. This allows which of the following?

The reviewers can determine the experiment’s feasibility.

The reviewers can determine the experiment’s validity.

The reviewers can include their own findings with the research.

The reviewers can determine if they will help fund the research.

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?

acetic acid

benzene

chloroform

water

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

Which statement is true about crystal lattice energy?

It increases as the size of the ions increases.

It increases as the charge on the ions decreases.

It is the energy that ions absorb when they form a crystal.

It is a measure of the strength of the bonds between ions.

In an experiment, a student wants to increase the rate of a reaction that involves gases. Which change to the reactants would accomplish this?

Increase the volume to decrease pressure and to increase concentration.

Increase the volume to increase pressure and to decrease concentration.

Decrease the volume to decrease pressure and to increase concentration.

Decrease the volume to increase pressure and to increase concentration.

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

Energy is removed from the particles in each change, but more energy is removed in melting than in boiling because the attractions are weaker.

Energy is removed from the particles in each change, but more energy is removed in boiling than in melting because the attractions are weaker.

Energy is added to the particles in each change, but boiling requires more energy than melting because the attractions must be completely overcome.

Energy is added to the particles in each change, but melting requires more energy than boiling because the attractions must be completely overcome.

Which is the formula mass of Na2SO4?

119.06 amu

125.98 amu

142.05 amu

174.12 amu

An atom bonds with another atom. What is the best classification for this reaction?

endothermic

chemical

nuclear

redox

Which compound contains both sigma and pi bonds?

HCCl3

H2CO

H2S

HBr

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

CuI2 + Br2

Cl2 + AlF3

Br2 + NaCl

CuF2 + I2

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

Most of the volume of a gas is empty space.

All collisions between particles are perfectly elastic.

There is no force of attraction or repulsion between gas particles.

The average kinetic energy of particles depends only on temperature.

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

1:2 and 1:4

1:3 and 1:4

1:2 and 3:5

1:3 and 3:5

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

1.53 mol

3.07 mol

110. mol

175. mol

How does heat differ from temperature?

Temperature is the measure of heat.

Temperature and heat are the same thing.

Temperature measures thermal energy, and heat is the flow of thermal energy.

Temperature measures the loss of energy, and heat measures the gain of energy.

During photosynthesis, sunlight shining on a plant is absorbed. Through several chemical reactions, the plant produces sugar, a high-energy compound, from simpler substances. What energy transformation occurs during this process?

thermal energy to chemical energy

electromagnetic energy to chemical energy

kinetic energy to potential energy

potential energy to chemical energy

A sample of water is taken and kept in a beaker in a freezer at a constant temperature of 0°C. If the system is at dynamic equilibrium, which of these statements is true?

The rate of freezing is equal to the rate of melting.

The rate of freezing is greater than the rate of melting.

The amount of ice is greater than the amount of water.

The amount of ice is equal to the amount of water.

The periodic table below shows the electronegativity values of some elements.ElectronegativitiesConsider the positions of barium (Ba), sulfur (S), silicon (Si), and calcium (Ca) on the periodic table. The atoms of which element require the least amount of energy to give up an electron when forming chemical bonds?

barium

sulfur

silicon

calcium

A solar panel combines multiple photovoltaic cells. Which type of energy is used to power a solar panel?

kinetic energy

thermal energy

electromagnetic energy

gravitational potential energy

Lillian multiplies two numbers as follows: A B = C. Given that A has five significant figures and two decimal places and B has six significant figures and four decimal places, which equals the number of significant figures in C?

two

four

five

six

Which is a characteristic of nuclear fission?

releases nonradioactive waste only

involves the collision of two nuclei

releases small amounts of energy compared to fossil fuels

involves the splitting of an atom into two or more fragments

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