Chemistry Midterm

What is the total charge of the nucleus of a nitrogen atom? A) +5 B) +2 C) +7 D) +14

A) +5

What is the mass number of a carbon atom that contains six protons, eight neutrons, and six electrons? A) 14 B) 6 C) 8 D) 20

A) 14

What is the minimum number of joules of heat energy needed to change 100. Grams of water to vapor at its normal boiling point? A) 226,000 B) 33,400 C) 2,260 D) 418

A) 226,000

Which sample at STP has the same number of molecules as 5 liters of NO2(g) at STP? A) 5 liters of CH4(g) B) 5 grams of H2(g) C) 5 moles of O2(g) D) 5 x 1023 molecules of CO2(g)

A) 5 liters of CH4(g)

At STP, which element has a definite shape and volume? A) Ag B) Xe C) Ne D) Hg

A) Ag

A student observed the following reaction: AlCl3(aq) + 3NaOH(aq)—->Al(OH)3(s) + NaCl(aq) After products were filtered with substance remained on the filter paper? A) Al(OH)3 B) AlCl3 C) NaOH D) NaCl

A) Al(OH)3

Which formula represents an iconic compound? A) K2O B) CO2 C) H2O D) SO2

A) K2O

Which statement describes a chemical property of the element magnesium? A) Magnesium reacts with an acid. B) Magnesium conducts electricity. C) Magnesium is malleable. D) Magnesium has a high boiling point.

A) Magnesium reacts with an acid.

According to the wave-mechanical model of the atom, electron in an atom A) are located in orbitals outside the nucleus B) travel in defined circles C) are most likely found in an excited state D) have a positive charge

A) are located in orbitals outside the nucleus

Which of the following Group 15 elements has the greatest metallic character? A) bismuth B) phosphorus C) nitrogen D) antimony

A) bismuth

Atoms of which elements have the strongest attraction for electrons? A) chlorine B) aluminum C) silicon D) sodium

A) chlorine

An aqueous solution of sodium chloride is best classified as a A) homogeneous mixture B) heterogeneous compound C) homogeneous compound D) heterogeneous mixture

A) homogeneous mixture

the bond in the compound MgSO4 can be described as A) ionic, only B) covalent, only C) neither ionic nor covalent D) both ionic and covalent

A) ionic, only

Which substance can be decomposed by chemical means? A) methane B) antimony C) krypton D) tungsten

A) methane

Based on the Vapor Pressure of Four Liquids chemistry reference table, which substance has the weakest intermolecular forces? A) propanone B) ethanoic acid C) ethanol D) water

A) propanone

Real gas behavior deviates from ideal gas behavior because real gas particles have A) volume and some attraction for each other B) volume but no attraction for each other C) no volume but some attraction for each other D) no volume and no attraction for each other

A) volume and some attraction for each other

What is the total number of electron in a Mg2+ ion? A) 12 B) 10 C) 24 D) 14

B) 10

At STP, an element that is a brittle solid and a poor conductor of heat and electricity could have an atomic number of A) 17 B) 16 C) 13 D) 12

B) 16

A rigid cylinder with a movable piston contains a 2.0-liter sample of neon gas at STP. What is the volume of this sample when its temperature is increased to 30. C while its pressure is decreases to 90. Kilopascals? A) 0.22 L B) 2.5 L C) 2.0 L D) 1.6 L

B) 2.5 L

What is the total number of joules of heat energy absorbed when the temperature of 200.0 grams of water is raised from 10.0C to 40.0C? A) 200. Joules B) 25,080 joules C) 33,440 joules D) 30.0 joules

B) 25,080 joules

A sample of helium gas has a volume of 900. Millimeters and a pressure of 2.50 atm at 298 K. What is the new pressure when the temperature is changed to 336 K and the volume is decreased to 450. Millimeters? A) 4.43 atm B) 5.64 atm C) 14.1 atm D) 0.177 atm

B) 5.64 atm

What was concluded about the structure of the atom as the result of the gold foil experiment? A) A negatively charged nucleus is surrounded by mostly empty space. B) A positively charged nucleus is surrounded by positively charged particles. C) A positively charged nucleus is surrounded by mostly empty space. D) a negatively charged nucleus is surrounded by positively charged particles.

B) A positively charged nucleus is surrounded by positively charged particles.

According to the kinetic theory of gases, which assumption is correct? A) The volume of gas particles prevents random motion. B) Energy may be transferred between colliding particles. C) Gas particles travel in curved paths. D) Gas particles strongly attract each other.

B) Energy may be transferred between colliding particles.

Which 5.0-millimeter sample of NH3 will take the shape of and completely fill a closed 100.0-millimeter contain? A) NH3(aq) B) NH3(g) C) NH3(l) D) NH3(s)

B) NH3(g)

Which list of elements contains two metaloides? A) As, Bi, Br, Kr B) Si, Ge, P.O., Pb C) Si, P, S, CL D) Po, Sb, I, Xe

B) Si, Ge, P.O., Pb

Given the balanced equation representing a reaction: CH4(g) + 2O2(g)——>2H2O(g) + CO2(g) + heat Which statement is true about energy in this reaction? A) The reaction is exothermic because it absorbs heat. B) The reaction is exothermic because it releases heat. C) The reaction is endothermic because it absorbs heat. D) The reaction is endothermic because it releases heat.

B) The reaction is exothermic because it releases heat.

Solid X is placed in contact with solid Y. Heat will flow spontaneously from X to Y when A) X is -25C and Y is -10C B) X is 10C and Y is 5 C) X is 20C and Y is 20C D) X is 25C and Y is 30C

B) X is 10C and Y is 5

A bottle of rubbing alcohol contained both 2-propanol and water. These liquids can be separated by the process of distillation because the 2-propanol and water A) have combined chemically and retain their different boiling points B) have combined physically and retain their different boiling points C) have combined physically and have the same boiling point D) have combined chemically and have the same boiling point

B) have combined physically and retain their different boiling points

As each successive element in Group 15 of the Periodic Table is considered in order of increasing atomic number, the atomic radius A) remains the same B) increases C) decreases

B) increases

The high electrical conductivity of metals is primarily due to A) filled energy levels B) mobile electrons C) high electronegativities D) high ionization energies

B) mobile electrons

In which simple is the average kinetic energy of the particles greatest? A) 15 mL of H2O9(l) at 30C B) 15 mL of HCL(aq) at 20C C) 10 mL of H2O(l) at 35C D) 10 mL of HCl(aq) at 25C

C) 10 mL of H2O(l) at 35C

A 100. Millimeter sample of gas at a pressure of 50.6 5 kPa is reduced to 25.33 kPa at constant temperature. What is the new volume of the gas? A) 90.0 mL B) 200. ML C) 290. ML D) 50.0 mL

C) 290. ML

What is the total number of electrons in the valence shell of an atom of aluminum in the group state? A) 8 B) 2 C) 3 D) 10

C) 3

How many kilojoules of heat are needed to raise the temperature of 500. Grams of water from 10.0C to 30.0C? A) 2.09 kJ B) 62.7 kJ C) 41.8 kJ D) 10.0 kJ

C) 41.8 kJ

Which phase change is endothermic? A) NH3(g)—->NH3(l) B) Fe(l)—->Fe(s) C) CO2(s)—->CO2(g) D) H2O(l)—->H2O(s)

C) CO2(s)—->CO2(g)

Which compound contains a bond with the greatest degrees of ionic character? A) PH3 B)CCl4 C) CaO D) MgBr

C) CaO

Given the balanced equation representing a reaction: Cl2(g)—->Cl(g) + Cl(g) What occurs during this change? A) Energy is released and a bond is broken. B) Energy is absorbed and a bond is broken C) Energy is absorbed and a bond is broken D) Energy is released and a bond is formed

C) Energy is absorbed and a bond is broken

What occurs when an atom loses an electron? A) The atom's radius decreases and the atom becomes a negative ion B) The atom's radius increases and the atom become a positive ion. C) The atom's radius decreases and the atom becomes a positive ion. D) The atom's radius increases and the atom becomes a negative ion.

C) The atom's radius decreases and the atom becomes a positive ion.

A substance that has a melting point of 1,074 K conducts electricity when dissolved in water, but does not conduct electricity in the solid phase. The substance is most likely A) a molecular solid B) a network solid C) an ionic solid D) a metallic solid

C) an ionic solid

Under what conditions does a real gas behave most like an ideal gas? A) at high temperature and high pressures B) at low temperatures and high pressures C) at high temperatures and low pressures D) at low temperatures and low pressures

C) at high temperatures and low pressures

On the present Periodic Table of Elements, the elements are arranged according to increasing A) number of oxidation states B) atomic mass C) atomic number D) number of neutrons

C) atomic number

From which of these atoms in the ground state can a valence electron be removed using the least amount of energy? A) chlorine B) nitrogen C) carbon D) oxygen

C) carbon

As the temperature of liquid water decreases, its vapor pressure A) increases B) remains the same C) decreases

C) decreases

At 65C, which of the following compounds have a vapor pressure of 58 kilopascals? A) propanone B) ethanoic acid C) ethanol D) water

C) ethanol

Which two particles make up most of the mass of a hydrogen-2 atom? A) electron and neutron B) proton and neutron C) proton and positron D) electron and proton

C) proton and positron

Matter is classified as a A) homogenous mixture, only B) substance, only C) substance or as a mixture substances D) homogeneous mixture or as a heterogeneous mixture

C) substance or as a mixture substances

At atom of helium-4 differs from an atom of lithium-7 in that at atom of helium-4 has A) one more neutron B) one more proton C) two less neutrons D) two less protons

C) two less neutrons

Which electron configuration represents and atom in an excited state? A) 2-7 B) 2-8-1 C) 2-8-8-2 D) 2-6-2

D) 2-6-2

Which kelvin temperature is equal to 56C? A) 217 K B) -217K C) -329K D) 329K

D) 329K

A gas occupies a volume of 30 millimeters at 273 K. If the temperature is increased to 364 K while the pressure remains constant, what will be the volume of the gas? A) 60 mL B) 20 mL C) 30 mL D) 40 mL

D) 40 mL

How many joules of heat energy are needed to completely melt 25.0 grams of ice to water at 0C? A) 105 J B) 56,500 J C) 334 J D) 8,350 J

D) 8,350 J

Molecule-ion attractions are found in A) NaCl(aq) B) KBr(l) C) Cu(s) D) CO(g)

D) CO(g)

According to the kinetic molecular theory, which of the following statements describes the particles in a sample of an ideal gas? A) The force of attraction between the gas particles is strong. B) The collisions between the gas particles cannot result in a transfer of energy between the particles. C) The separation between the gas particles is smaller than the size of the gas particles themselves D) The motion of the gas particles is random and straight-line.

D) The motion of the gas particles is random and straight-line.

Tetrachloromethane, CCl4, is classified as a A) mixture because the atoms of the elements are combined in a fixed proportion B) mixture because the atoms of the elements are combined in a proportion that varies C) compound because the atoms of the elements are combined in a proportion that varies D) compound because the atoms of the elements are combined in a fixed proportion

D) compound because the atoms of the elements are combined in a fixed proportion

At STP, solid carbon can exist as graphite or as diamond. These forms of carbon have A) different properties and the same crystal structures B) the same properties and the same crystal structures C) the same properties and different crystal structures D) different properties and different crystal structures

D) different properties and different crystal structures

The volume of a given mass of an ideal gas at constant pressure is A) inversely proportional to a Celsius temperature B) directly proportional to the Celsius temperature C) inversely proportional to the Kelvin temperature D) directly proportional to the Kelvin temperature

D) directly proportional to the Kelvin temperature

The electron in a bond between two iodine atoms (I2) are shared A) equally, and the resulting bond is polar B) unequally, and a resulting bond is polar C) unequally, and a resulting bond is nonpolar D) equally, and the resulting bond is nonpolar

D) equally, and the resulting bond is nonpolar

Which element is malleable and conducts electricity? A) sulfur B) phosphorus C) iodine D) iron

D) iron

Which of the following total masses is the smallest? A) mass of 1 neutron plus the mass of 1 electron B) mass of 2 neutrons C) mass of 1 electron plus the mass of 1 proton D) mass of 2 electrons

D) mass of 2 electrons

Solid ZnCl2 and liquid ZnCl2 have different A) empirical formulas B) ion ratios C) formula masses D) physical properties

D) physical properties

The phase change represented by the equation I2(s)—->I2(g) is called A) condensation B) boiling C) melting D) sublimation

D) sublimation