Q&A Hero

Q: The substances that are formed by a chemical reaction are called the A) products. B) reactants. C) chemicals. D) precipitates.

Q: A chemical reaction is at equilibriumwhen A) no reactants are changing to products. B) the forward and reverse reactions proceed at the same rate. C) the total mass has become constant. D) the temperature is no longer changing.

Q: Which of the following does nottake place in a chemical reaction? A) New substances are formed. B) Neutrons are released. C) Energy is released or absorbed. D) Reactants disappear.

Q: Which of the following is a chemical change? A) Dry ice subliming B) Limestone being crushed to powder C) Paper being shredded D) Sulfur burning

Q: Which of the following is an example of a chemical property?A) Al has a density of 2.70 g/cm3.B) Diamond is the hardest substance known.C) Limestone will yield CO2when heated.D) CO2will freeze at -78C.

Q: The process of melting lead is an example of A) a physical change. B) a chemical change. C) a physical property. D) a chemical property.

Q: Which one of the following is a physical change? A) Rusting of iron B) Fermenting of grape juice C) Souring of milk D) Sharpening a pencil

Q: Which one of the following is nota physical property of matter? A) Specific heat B) Boiling point C) Density D) Flammability

Q: One reactant of photosynthesis is A) hydrogen. B) oxygen. C) carbon dioxide. D) methane.

Q: One product of photosynthesis is A) hydrogen. B) oxygen. C) carbon dioxide. D) methane.

Q: Water has unusual physical properties, as compared with H2S, H2Se, and H2Te, because of ______________ bonding.

Q: The symbol for the element that is the major component of steel is ______________.

Q: Ice is less dense than liquid water because of ______________ bonding.

Q: The dipole arrow in an SSe bond would point toward the ______________ atom.

Q: The dipole arrow in an FO bond would point toward the ______________ atom.

Q: A(n) ______________ covalent bond is one in which the electrons are shared unequally.

Q: ______________ is the measure of the ability of an atom to attract shared electrons to itself.

Q: Compounds that occur in gaseous form at room temperature are ______________ compounds.

Q: In a covalent molecule, each atom (except hydrogen) generally has ______________ electrons in its outer shell.

Q: When forming covalent compounds, atoms ______________ electrons.

Q: The symbol for the element with the highest electronegativity is ______________.

Q: The crucial test of whether a compound is ionic is whether, when melted, it __________________.

Q: A positively charged ion is called a(n) ______________.

Q: The formula for the ionic compound sodium nitride is ______________.

Q: A compound formed from atoms from the far left and the far right of the periodic table is probably a(n) ______________ compound.

Q: In the ______________ phase, ionic compounds conduct electricity.

Q: When forming ionic compounds, atoms ______________ electrons.

Q: The concept that atoms tend to get eight electrons in their outer shell when forming molecules or ions is called the ______________.

Q: Mn is a transition element and can form several ions. Its ionic charge in MnF3 must be ______________.

Q: If aluminum arsenate is AlAsO4, the ionic charge on the arsenate ion must be ______________.

Q: If 20.0 g of compound XY decomposes to form 12.0 g of element X and 8.00 g of element Y, ______________ g of element X will be formed by the decomposition of 40.0 g of compound XY.

Q: The percentage composition by mass (to the nearest 0.1) of C in sugar, C12H22O11, is _____________.

Q: The statement "Different samples of a pure compound always contain the same elements in the same proportion by mass" is known as the law of ______________.

Q: The formula mass of acetic acid, HC2H3O2, is ______________ u.

Q: The ______________ of a compound is the sum of the atomic masses given in the formula of the compound.

Q: The statement "No detectable change in the total mass occurs during a chemical reaction" is known as the law of ______________.

Q: Before it was found that when a substance burns, it is combining with oxygen, it was hypothesized that the burning material released a substance called ______________.

Q: In the Lewis symbol for an atom of bromine, there are ______________ (how many?) dots around the Br.

Q: In 400 B.C., a Greek named ______________ championed the idea that if matter were repeatedly cut into smaller divisions, eventually an indivisible particle would be reached.

Q: Which of the following elements commonly forms an ion with a 2+ charge? A) Li B) Al C) S D) Ca

Q: Which of the following ions is isoelectronic with an argon atom? A) Cl- B) Na+ C) F- D) S2+

Q: The formula mass of Na2S is A) 55.1 u. B) 30.1 u. C) 78.1 u. D) 57.1 u.

Q: The formula for iron(II) sulfate is A) Fe2SO4. B) Fe2(SO4)2. C) Fe(SO4)2. D) FeSO4.

Q: The preferred name of NiS is A) nickel(III) sulfide. B) nickel(II) sulfide. C) nickel(I) sulfide. D) nickel sulfide.

Q: Which of the following compounds should be named using the Stock system? A) Ag2O B) Au2S C) ZnO D) Al2O3

Q: The Stock system of nomenclature uses A) Roman numerals. B) Greek prefixes. C) Arabic numerals. D) Egyptian hieroglyphics.

Q: Ion-dipole interactions are responsible for A) the dissolving of salt in water. B) ice being less dense than water. C) the ease of electrolysis of water. D) metallic bonding in steel.

Q: Ammonia, NH3, boils at a higher temperature than phosphine, PH3. This is probably due to A) ammonia being more dense than PH3. B) ammonia having the lower formula mass. C) hydrogen bonding among the NH3 molecules. D) ammonia being ionic and phosphine being covalent.

Q: A hydrogen bond can be formed between A) an atom of H and one of C, P, or Cl in the same molecule. B) an H atom in one molecule and an O, F, or N atom in another. C) an atom of H in one water molecule and an atom of H in another. D) the H atoms in H2 molecules.

Q: In which of the following compounds would hydrogen bonding not be expected among the molecules? A) NH3 B) CH4 C) H2O D) HF

Q: In chlorine gas, the bond between the two chlorine atoms is A) ionic. B) single covalent. C) triple covalent. D) double covalent.

Q: A water molecule is A) angular and nonpolar. B) linear and polar. C) linear and nonpolar. D) angular and polar.

Q: Which of these compounds would be ionic? A) NO2 B) CCl4 C) LiF D) H2S

Q: A stream of a certain liquid compound is not attracted to an electrically charged rod. The compound is probably A) metallic. B) ionic. C) nonpolar covalent. D) polar covalent.

Q: Electronegativity increases ______________ across a period and ______________ in a group. A) right to left; bottom to top B) left to right; top to bottom C) right to left; top to bottom D) left to right; bottom to top

Q: A stream of a certain liquid compound is attracted to an electrically charged rod. The compound is probably A) metallic. B) nonpolar covalent. C) ionic. D) polar covalent.

Q: In the liquid phase, covalent compounds generally conduct electricity A) not at all. B) very well. C) better than metals. D) better than ionic compounds in the liquid phase.

Q: Which gas gives the characteristic odor to smelling salts and some household cleaners? A) Ammonia B) Carbon dioxide C) Chlorine D) Ozone

Q: Which compound is the major component of table salt? A) HC2H3O2 B) NH4Cl C) MgCO3 D) NaCl

Q: Compounds formed when the atoms involved share electrons are A) electrovalent. B) covalent. C) ionic. D) organic.

Q: In the HCl molecule, the bonding electrons spend A) equal time around both atoms. B) all their time around only one of the atoms. C) more time around the H atom. D) more time around the Cl atom.

Q: Compound A is a liquid and compound B is a solid. Which statement is justified? A) Compound A is covalent; compound B is ionic. B) Compound A is ionic; compound B is covalent. C) Compound A could be ionic or covalent; compound B is ionic. D) Compound A is covalent; compound B could be ionic or covalent.

Q: Which of the following compounds contains both ionic and covalent bonds? A) CaSO4 B) CHCl3 C) HNO3 D) C12H22O11

Q: The CO molecule would A) probably be nonpolar. B) definitely be nonpolar. C) definitely be polar. D) probably be polar.

Q: Which pair of elements is least likely to form an ionic bond? A) K and H B) Al and F C) N and Cl D) S and Sr

Q: When atoms of two elements with a medium difference in electronegativity bond together, the bonding is probably A) ionic. B) covalent. C) polar covalent. D) metallic.

Q: When atoms of two elements with a great difference in electronegativity bond together, the bonding is probably A) ionic. B) polar covalent. C) covalent. D) metallic.

Q: A methane molecule is A) flat and polar. B) flat and nonpolar. C) tetrahedral and nonpolar. D) pyramidal and polar.

Q: An ammonia molecule is A) pyramidal and polar. B) pyramidal and nonpolar. C) flat and polar. D) flat and nonpolar.

Q: A carbon dioxide molecule is A) linear and polar. B) angular and polar. C) linear and nonpolar. D) angular and nonpolar.

Q: A Group 7A element would be most likely to form a covalent bond with elements of Group A) 2A. B) 1A. C) 8A. D) 6A.

Q: Compounds tend to be ______________ compounds if they are formed from two or more nonmetals. A) covalent B) organic C) polar D) ionic

Q: Two atoms of hydrogen bond with an atom of oxygen to form a water molecule. This bonding is A) covalent only. B) polar only. C) both covalent and polar. D) none of these.

Q: If two atoms have equal electronegativity, a bond formed between them is generally A) ionic. B) nonpolar. C) very weak. D) polar.

Q: If two atoms have five electrons in the valence shell and are covalently bound, the molecule has a ______________ bond. A) quadruple B) double C) triple D) single

Q: A pair of electrons shared by two atoms forms A) a metallic bond. B) a double covalent bond. C) a single covalent bond. D) an ionic bond.

Q: When hydrogen, from Group 1A, unites with chlorine, it forms a(n) ______________ compound. A) ionic B) metallic C) covalent D) organic

Q: When atoms unite by transferring electrons, they should form A) a polar molecule. B) a covalent compound. C) an ionic compound. D) an organic compound.

Q: The sharing of two electrons by unlike atoms generally forms a(n) ______________ bond. A) ionic B) metallic C) nonpolar D) polar covalent

Q: Which of the following compounds would be expected to be hard and brittle and to have a high melting point? A) H2SO4 B) KBr C) H2C2O4 D) IF7