Chem Aug 2010 Regents

Which compound is insoluble in water?    

• KOH

• NH4Cl

• Na2SO4

• PbSO4

Which nuclide is listed with its half-life and decay mode? 

• K-37, 1.24 h, α

• N-16, 7.2 s, β−

• Rn-222, 1.6 × 10^3 y, α

• U-235, 7.1 × 10^8 y, β−

Which compound has both ionic and covalent bonds

• CO2

• CH3OH

• NaI

• Na2CO3

What is the total number of electrons shared in a double covalent bond? 

• 1

• 2

• 3

• 4

Which substance can not be broken down by a chemical change? 

• Methane

• Propanal

• Tungsten

• Water

Which gas sample at STP has the same total number of molecules as 2.0 liters of CO2(g) at STP? 

• 5.0 L of CO2(g)

• 2.0 L of Cl2(g)

• 3.0 L of H2S(g)

• 6.0 L of He(g)

Based on the results of testing colorless solutions with indicators, which solution is most acidic? 

• A solution in which bromthymol blue is blue

• A solution in which bromcresol green is blue

• A solution in which phenolphthalein is pink

• A solution in which methyl orange is red

According to one acid-base theory, water acts as an acid when an H2O molecule 

• Accepts an H+

• Donates an H+

• Accepts an H-

• Donates an H-

Which element forms an ionic compound when it reacts with lithium? 

• K

• Fe

• Kr

• Br

What is the minimum amount of heat required to completely melt 20.0 grams of ice at its melting point? 

• 20.0 J

• 83.6 J

• 6680 J

• 45 200 J

As the temperature of a chemical reaction in the gas phase is increased, the rate of the reaction increases because 

• Fewer particle collisions occur

• More effective particle collisions occur

• The required activation energy increases

• The concentration of the reactants increases

An atom of which element has the largest atomic radius? 

• Fe

• Mg

• Si

• Zn

Which unit can be used to express the concentration of a solution? 

• L/s

• J/g

• Ppm

• KPa

Which element is present in all organic compounds? 

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

The table below shows the number of subatomic particles in atom X and in atom Z.     Atom X and atom Z are isotopes of the element    

• Aluminum

• Carbon

• Magnesium

• Nitrogen

The entropy of a sample of CO2 increases as the CO2 changes from 

• Gas to liquid

• Gas to solid

• Liquid to solid

• Solid to gas

Which isotope is used to treat cancer?    

• C-14

• U-238

• Co-60

• Pb-206

Each of four test tubes contains a different concentration of HCl(aq) at 25°C. A 1-gram cube of Zn is added to each test tube. In which test tube is the reaction occurring at the fastest rate? 

What is the total number of valence electrons in a calcium atom in the ground state? 

• 8

• 2

• 18

• 20

Which subatomic particles are located in the nucleus of an He-4 atom? 

• Electrons and neutrons

• Electrons and protons

• Neutrons and protons

• Neutrons, protons, and electrons

In the late 1800s, experiments using cathode ray tubes led to the discovery of the 

• Electrons

• Neutrons

• Protons

• Positrons

Which element requires the least amount of energy to remove the most loosely held electron from a gaseous atom in the ground state? 

• Bromine

• Calcium

• Sodium

• Silver

The percent composition by mass of nitrogen in NH4OH (gram-formula mass = 35 grams/mole) is equal to 

Which formula represents a mixture?

• C6H12O6 (l)

• C6H12O6 (s)

• LiCl (aq)

• LiCl (s)

Petroleum can be separated by distillation because the hydrocarbons in petroleum are 

• Elements with identical boiling points

• Elements with different boiling points

• Compounds with identical boiling points

• Compounds with different boiling points

Which sample has particles with the lowest average kinetic energy?

• 1.0 g of Br2 at 50.°C

• 2.0 g of Br2 at 30.°C

• 7.0 g of Br2 at 40.°C

• 9.0 g of Br2 at 20.°C

Which energy conversion occurs during the operation of an electrolytic cell? 

• Chemical energy to electrical energy

• Electrical energy to chemical energy

• Nuclear energy to electrical energy

• Electrical energy to nuclear energy

 Which compound is an Arrhenius acid?    

• CaO

• HCl

• NaOH

• NH3

In the formula X2(SO4)3, the X represents a metal. This metal could be located on the Periodic Table in 

• Group 1

• Group 2

• Group 13

• Group 14

Given the balanced equation representing a reaction: 2NaCl(l) → 2Na(l) + Cl2(g) A 1170.-gram sample of NaCl(l) completely reacts, producing 460. grams of Na(l). What is the total mass of Cl2(g) produced? 

• 355 g

• 710 g

• 1420 g

• 1630 g

Given the formula representing a hydrocarbon:     The molecular formula and the empirical formula for this hydrocarbon are 

• C5H10 and CH2

• C5H10 and CH3

• C4H8 and CH2

• C4H8 and CH3

The reaction between an organic acid and an alcohol produces 

• An aldehyde

• A ketone

• An ether

• An ester

In which type of reaction is an atom of one element converted to an atom of a different element? 

• Decomposition

• Neutralization

• Transmutation

• Saponification

The atomic mass of titanium is 47.88 atomic mass units. This atomic mass represents the 

• Total mass of all the protons and neutrons in an atom of Ti

• Total mass of all the protons, neutrons, and electrons in an atom of Ti

• Weighted average mass of the most abundant isotope of Ti

• Weighted average mass of all the naturally occurring isotopes of Ti

Which Group 15 element exists as diatomic molecules at STP? 

• Phosphorus

• Nitrogen

• Bismuth

• Arsenic

Object A at 40.°C and object B at 80.°C are placed in contact with each other. Which statement describes the heat flow between the objects? 

• Heat flows from object A to object B.

• Heat flows from object B to object A.

• Heat flows in both directions between the objects.

• No heat flow occurs between the objects.

A gas sample is at 25°C and 1.0 atmosphere. Which changes in temperature and pressure will cause this sample to behave more like an ideal gas? 

• Decreased temperature and increased pressure

• Decreased temperature and decreased pressure

• Increased temperature and increased pressure

• Increased temperature and decreased pressure

At STP, which element is solid, brittle, and a poor conductor of electricity? 

• Al

• K

• Ne

• S

A cylinder with a movable piston contains a sample of gas having a volume of 6.0 liters at 293 K and 1.0 atmosphere. What is the volume of the sample after the gas is heated to 303 K, while the pressure is held at 1.0 atmosphere? 

• 9.0 L

• 6.2 L

• 5.8 L

• 4.0 L

Every water molecule has two hydrogen atoms bonded to one oxygen atom. This fact supports the concept that elements in a compound are 

• Chemically combined in a fixed proportion

• Chemically combined in proportions that vary

• Physically mixed in a fixed proportion

• Physically mixed in proportions that vary

Given the balanced equation representing a reaction: Br2 +energy→Br+Br Which statement describes the energy change and bonds in this reaction? 

• Energy is released as bonds are broken.

• Energy is released as bonds are formed.

• Energy is absorbed as bonds are broken.

• Energy is absorbed as bonds are formed.

The isotopes K-37 and K-42 have the same   

• Decay mode

• Bright-line spectrum

• Mass number for their atoms

• Total number of neutrons in their atoms

32. The greatest composition by mass in an atom of oxygen-18 is due to the total mass of its 

• Electrons

• Neutrons

• Protons

• Positrons

Which balanced equation represents a redox reaction? 

• AgNO3(aq)+NaCl(aq)→AgCl(s)+NaNO3(aq)

• H2CO3(aq) → H2O(l) + CO2(g)

• NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

• Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

Which formula represents an unsaturated hydrocarbon? 

• C5H12

• C6H14

• C7H16

• C8H14

A balanced equation representing a chemical reaction can be written using 

• Chemical formulas and mass numbers

• Chemical formulas and coefficients

• First ionization energies and mass numbers

• First ionization energies and coefficients

Given the formula representing a molecule:     The molecule is 

• Symmetrical and polar

• Symmetrical and nonpolar

• Asymetrical and polar

• Asymmetrical and nonpolar

A solution with a pH of 2.0 has a hydronium ion concentration ten times greater than a solution with a pH of 

• 1.0

• 0.20

• 3.0

• 20.