Chemistry Exam 1

Chapters 1, 2, and 3

What do chemical formulas represent?

Chemical formulas show the ratio of atoms in a compound.

What is a formula unit?

A formula unit represents the ratio of atoms in an ionic compound.

How many atoms of each element are in Mg(ClO3)2?

1 Mg, 2 Cl, and 6 O.

How many atoms of each element are in (NH4)2SO3?

2 N, 8 H, 1 S, and 3 O.

What is the structure of covalent compounds?

Covalent compounds exist as individual units known as molecules.

What are the seven diatomic elements?

H2, N2, O2, F2, Cl2, Br2, and I2.

What are allotropes?

Different molecular forms of an element

What is the chemical formula for molecular oxygen?

O2.

What prefix is used for 1 atom in binary covalent compounds?

Mono-.

What prefix is used for 2 atoms in binary covalent compounds?

Di-.

What prefix is used for 3 atoms in binary covalent compounds?

Tri-.

How do you name a binary covalent compound?

Name the first element with a prefix if greater than 1, and the second element with a prefix and modify to end with -ide.

What is the name of the compound N2O?

Dinitrogen monoxide.

What is the name of the compound P2O5?

Diphosphorus pentoxide.

What is the name of the compound SO3?

Sulfur trioxide.

What is the formula for dinitrogen pentoxide?

N2O5.

What is the formula for chlorine dioxide?

ClO2.

What is the significance of subscripts in chemical formulas?

Subscripts indicate how many atoms of that type are in one formula unit.

What is the chemical formula for ammonia?

NH3.

What is the chemical formula for phosphine?

PH3.

What is the chemical formula for arsine?

AsH3.

What does a subscript outside of parentheses indicate?

It applies to each element inside the parentheses as a multiplier.

What type of atoms do covalent compounds contain?

Covalent compounds contain only nonmetal atoms.

How are prefixes used in naming binary covalent compounds?

Prefixes indicate the number of atoms of each type present.

What is chemical nomenclature?

The systematic approach to naming chemical compounds established by IUPAC.

What structure do ionic compounds exist in?

An extended 3-D lattice structure.

What types of ions are present in ionic compounds?

Cations (positive ions) and anions (negative ions).

How are ionic compounds formed?

When metal atoms transfer electrons to nonmetal atoms.

What is a cation?

A positive ion formed when an atom loses electrons.

What is an anion?

A negative ion formed when an atom gains electrons.

What are monatomic ions?

Ions formed from single atoms that gain or lose electrons.

What is the only common positive polyatomic cation?

Ammonium

What is the naming convention for ionic compounds?

The names consist of the names of the two ions present.

What is a hydrate?

An ionic compound that contains water molecules within its solid structure.

How is a hydrate named?

By adding a prefix indicating the number of water molecules + 'hydrate' to the compound name.

What are oxyanions?

Polyatomic anions that contain oxygen along with another element.

What suffixes are used in naming oxyanions?

-ate and -ite, with prefixes per- and hypo- for variations in oxygen count.

What is the difference between monoprotic and polyprotic acids?

Monoprotic acids release one H+ ion, while polyprotic acids can release more than one.

What is the formula for zinc nitrate?

Zn(NO3)2.

What is the formula for cobalt(III) hypochlorite?

Co(ClO)3.

What happens to a hydrate when it is heated?

It produces the anhydrous form of the compound.

What are constant-charge cations?

Monatomic metal ions that always have the same charge.

What are variable-charge cations?

Monatomic metal ions that can have more than one charge, indicated with Roman numerals.

How are monatomic anions named?

Using the root of the element name with the suffix -ide.

What is the formula for copper(II) sulfate pentahydrate?

CuSO4 · 5 H2O.

What is the charge of the hydroxide ion?

OH−.

What is the formula for the sulfate ion?

SO4^2−.

What is the formula for the nitrate ion?

NO3−.

What is the formula for the phosphate ion?

PO4^3−.

What is the formula for the carbonate ion?

CO3^2−.

What is the formula for the bicarbonate ion?

HCO3−.

What are monoprotic acids?

Acids that have only one ionizable proton.

What are polyprotic acids?

Acids that have two or more ionizable protons.

What is the suffix for acids derived from anions ending in -ide?

Hydro___ic acid (e.g., HCl = hydrochloric acid).

What is the suffix for acids derived from anions ending in -ate?

___ic acid (e.g., HClO3 = chloric acid).

What is the suffix for acids derived from anions ending in -ite?

___ous acid (e.g., HClO2 = chlorous acid).

What is the first step in naming ionic compounds?

Determine if the compound is ionic or covalent.

How do you name an ionic compound that is a hydrate?

Add a prefix + hydrate to the name.

What is Avogadro's number?

6.022 × 10^23 units of a substance.

How many formula units are in one mole?

1 mol = 6.022 × 10^23 formula units.

How many moles of carbon are in 1 mol of sucrose, C12H22O11?

12 moles of carbon.

What is molar mass?

The mass of 1 mole of atoms expressed in grams.

How is the molar mass of a compound calculated?

It is the sum of the molar masses of all the atoms in a formula unit of the compound.

What is the formula for calculating moles?

Mass/Molar mass

What is the difference between empirical and molecular formulas?

Empirical formula is the simplest whole number ratio; molecular formula is the exact ratio.

What does combustion analysis determine?

The empirical formula of compounds containing C, H, and possibly O.

In combustion analysis, what do all carbon atoms become?

Carbon dioxide (CO2).

In combustion analysis, what do all hydrogen atoms become?

Water (H2O).

How do you calculate percent composition?

Percent composition = (mass of element in 1 mol of compound / molar mass of compound) × 100%.

What is the molar mass of sodium chloride (NaCl)?

58.44 g/mol.

What is the empirical formula for a compound containing 0.0300 mol C and 0.0600 mol H?

CH2.

What does the term 'formula mass' refer to?

The average mass of a formula unit of any type of substance, expressed in atomic mass units (u).

What is the relationship between atomic mass and molar mass?

They have the same numerical value but are expressed in different units (u for atomic mass and g/mol for molar mass).

What is chemistry?

The study of matter and the changes it goes through

What is matter?

Anything that has mass and occupies space

What are quantitative properties?

Properties that can be measured

What is the SI unit for length?

Meter (m)

What is the SI unit for mass?

Kilogram (kg)

What is the SI unit for time?

Second (s)

What is the SI unit for temperature?

Kelvin (K)

What is the SI unit for electric current?

Ampere (A)

What is the SI unit for the amount of substance?

Mole (mol)

What is the SI unit for luminous intensity?

Candela (cd)

What is mass?

A measure of the amount of matter in an object or sample

What is the difference between mass and weight?

Mass does not change regardless of location, while weight varies with gravity

What is the freezing point of water in Celsius?

0°C

What is the boiling point of water in Celsius?

100°C

What is absolute zero in Kelvin?

0 K

What is the formula for converting Celsius to Kelvin?

°C + 273.15 = K

What is the SI unit for volume?

Cubic meter (m³)

What is the practical unit for volume in chemistry?

Liter (L)

How is density calculated?

Density = mass/volume

What are significant figures?

Meaningful digits in a reported number that indicate precision

What is an inexact number?

A number measured by any method other than counting

What is the significance of the last digit in a measured number?

It is the uncertain digit

What is the density of ice at 0°C?

0.92 g/cm³

What is the conversion factor for 1 dm³?

1 dm³ = 1 L = 10⁻³ m³

What is the freezing point of water in Fahrenheit?

32°F

What is the boiling point of water in Fahrenheit?

212°F

What is the formula for converting Celsius to Fahrenheit?

(32°F − 32) × 5/9 = 0°C