Compounds and Molecules - SAT Subject Test in Chemistry

There are six electron domains in . has five bonding and one nonbonding pairs of electrons. The electron domain geometry of is octahedral. When a molecule has octahedral electron domain geometry and has five bonding and one nonbonding pairs, the molecular geometry is square pyramidal.

has three bonding pairs and one non-bonding pair, which is the geometry for trigonal pyramidal, not trigonal planar.

In order to answer this question correctly, it is important to have knowledge of the formation of ionic bonds, polyatomic ions, and the periodic table. First, it is important to notice that calcium ions and sulfate ions will form an ionic bond. Knowing this, it can be understood that valance electrons will be exchanged between the ions and therefore, oppositely charged ions that are attracted to each other will be formed.

Calcium is in the second column of the periodic table, so it will provide two ions to the sulfate polyatomic ion. This will form a calcium cation () and a sulfate polyatomic anion ().

One calcium ion provides two electrons, which are both accepted by a sulfate polyatomic ion, so the ratio of calcium ions used to sulfate polyatomic ions used is 1:1. This means that only one of each ion is needed to form the compound, making the formula .

Initially it may be tempting to write the formula as ; however, since both ions have a "2" subscript in this form, it is redundant to the formula in this way. Only one of each ion is needed to form the compound.

In order to answer the question, it is important to first determine what kind of bonding is occurring in order to properly name the molecule. When nitrogen and oxygen form an molecule, electrons are shared between the atoms, so a covalent bond is formed.

Because a covalent bond is formed, we can determine that name of the molecule will be based on number of each atom in the molecule. There are two nitrogen atoms in the resulting molecule, so the prefix in front of the "nitrogen" part of the name will be "di-," meaning two. There are four oxygen atoms in the resulting molecule, so the prefix in front of the "oxygen" part of the name will be "tetra," meaning four.

The molecules names will be arranged alphabetically, and the second atom will have "-ide" as the suffix. Therefore, the correct answer is "dinitrogen tetroxide."

Strong electrolytes are substances that exists in solutions as only ions. These substances dissociate 100% in solutions. Strong acids, strong bases, and salts are all examples of strong electrolytes. is a strong acid. is a salt. is a salt. is a weak acid. is a weak base. Therefore the answer is three.

Physical properties are aspects of matter that can be observed and measured without changing it. Chemical properties measure the potential for undergoing a chemical change. How zinc reacts to acid and in moist air are both chemical properties because the zinc is undergoing chemical change in each environment. The color, density, and melting point of the zinc can all be observed without changing the nature of the matter, so these are physical properties of zinc.

Hydrogen bonding occurs between hydrogen and a very electronegative atom, which is usually fluorine, oxygen, or nitrogen. Thus, hydrogen bonding does not occur in .

An electrolyte is a substance that when dissolved in a solution breaks up into ions. More specifically, an electrolyte breaks up into cations (positively charged ions) and anions (negatively charged ions). While strong electrolytes break up 100% into anions and cations, weak electrolytes break apart significantly less. Less than 10% of a weak electrolyte ionizes at all in solution. That means the 90%–99% of the weak electrolyte's molecules do not ionize. This is because the intermolecular forces that form between the solution and the weak electrolyte's molecules are not stronger than the intramolecular forces holding the molecule together. While solutions containing weak electrolytes contain both ions formed from the weak electrolyte ions and molecules of the weak electrolyte, they contain mostly molecules of the weak electrolyte.

Ionic compounds are chemical compounds made of charged ions held together by forces called ionic bonding. Ionic bonds are formed by transfers of valance electrons, which create charged atoms (ions) which are attracted to each other because they have opposite charges. This is not be confused with covalent bonding, in which atoms form an attraction by sharing electrons.

contains a positively charged ion and negatively charged ion which form an ionic bond. contains two positively charged ions and a negatively charged ion which form an ionic bond. , , and are all examples of molecules that contain covalent bonds. None of them contains any charged ions. The answer is therefore "two,"referring to the and molecules.

There are six electron domains in . has five bonding and one nonbonding pairs of electrons. The electron domain geometry of is octahedral. When a molecule has octahedral electron domain geometry and has five bonding and one nonbonding pairs, the molecular geometry is square pyramidal.

has three bonding pairs and one non-bonding pair, which is the geometry for trigonal pyramidal, not trigonal planar.

In order to answer this question correctly, it is important to have knowledge of the formation of ionic bonds, polyatomic ions, and the periodic table. First, it is important to notice that calcium ions and sulfate ions will form an ionic bond. Knowing this, it can be understood that valance electrons will be exchanged between the ions and therefore, oppositely charged ions that are attracted to each other will be formed.

Calcium is in the second column of the periodic table, so it will provide two ions to the sulfate polyatomic ion. This will form a calcium cation () and a sulfate polyatomic anion ().

One calcium ion provides two electrons, which are both accepted by a sulfate polyatomic ion, so the ratio of calcium ions used to sulfate polyatomic ions used is 1:1. This means that only one of each ion is needed to form the compound, making the formula .

Initially it may be tempting to write the formula as ; however, since both ions have a "2" subscript in this form, it is redundant to the formula in this way. Only one of each ion is needed to form the compound.

In order to answer the question, it is important to first determine what kind of bonding is occurring in order to properly name the molecule. When nitrogen and oxygen form an molecule, electrons are shared between the atoms, so a covalent bond is formed.

Because a covalent bond is formed, we can determine that name of the molecule will be based on number of each atom in the molecule. There are two nitrogen atoms in the resulting molecule, so the prefix in front of the "nitrogen" part of the name will be "di-," meaning two. There are four oxygen atoms in the resulting molecule, so the prefix in front of the "oxygen" part of the name will be "tetra," meaning four.

The molecules names will be arranged alphabetically, and the second atom will have "-ide" as the suffix. Therefore, the correct answer is "dinitrogen tetroxide."

Strong electrolytes are substances that exists in solutions as only ions. These substances dissociate 100% in solutions. Strong acids, strong bases, and salts are all examples of strong electrolytes. is a strong acid. is a salt. is a salt. is a weak acid. is a weak base. Therefore the answer is three.

Physical properties are aspects of matter that can be observed and measured without changing it. Chemical properties measure the potential for undergoing a chemical change. How zinc reacts to acid and in moist air are both chemical properties because the zinc is undergoing chemical change in each environment. The color, density, and melting point of the zinc can all be observed without changing the nature of the matter, so these are physical properties of zinc.

Hydrogen bonding occurs between hydrogen and a very electronegative atom, which is usually fluorine, oxygen, or nitrogen. Thus, hydrogen bonding does not occur in .

An electrolyte is a substance that when dissolved in a solution breaks up into ions. More specifically, an electrolyte breaks up into cations (positively charged ions) and anions (negatively charged ions). While strong electrolytes break up 100% into anions and cations, weak electrolytes break apart significantly less. Less than 10% of a weak electrolyte ionizes at all in solution. That means the 90%–99% of the weak electrolyte's molecules do not ionize. This is because the intermolecular forces that form between the solution and the weak electrolyte's molecules are not stronger than the intramolecular forces holding the molecule together. While solutions containing weak electrolytes contain both ions formed from the weak electrolyte ions and molecules of the weak electrolyte, they contain mostly molecules of the weak electrolyte.

Ionic compounds are chemical compounds made of charged ions held together by forces called ionic bonding. Ionic bonds are formed by transfers of valance electrons, which create charged atoms (ions) which are attracted to each other because they have opposite charges. This is not be confused with covalent bonding, in which atoms form an attraction by sharing electrons.

contains a positively charged ion and negatively charged ion which form an ionic bond. contains two positively charged ions and a negatively charged ion which form an ionic bond. , , and are all examples of molecules that contain covalent bonds. None of them contains any charged ions. The answer is therefore "two,"referring to the and molecules.

There are six electron domains in . has five bonding and one nonbonding pairs of electrons. The electron domain geometry of is octahedral. When a molecule has octahedral electron domain geometry and has five bonding and one nonbonding pairs, the molecular geometry is square pyramidal.

has three bonding pairs and one non-bonding pair, which is the geometry for trigonal pyramidal, not trigonal planar.