Chemistry Laboratory Techniques: Equipment, Chemical Equations, Nomenclature, and Redox Reactions

Comprehensive practice flashcards covering basic chemistry laboratory apparatus and equipment, rules and examples for balancing chemical equations, assigning oxidation states, IUPAC and common nomenclature of chemical compounds, and balancing redox equations via the oxidation number and half-reaction methods.

What is the primary function of an alcohol lamp in the laboratory?

To provide a controlled and consistent flame for heating and sterilization purposes.

What is the purpose of using an amber bottle for chemical storage?

It protects light-sensitive substances from degradation or decomposition by blocking harmful UV rays.

Which laboratory apparatus measures mass with high precision and accuracy for analytical and quantitative experiments?

Analytical balance

What is a beaker typically used for during laboratory procedures?

Mixing, heating, and holding liquids.

What apparatus determines the calorific value of substances by measuring the heat released during combustion?

Bomb calorimeter

What is the role of a Bunsen burner in laboratory settings?

To provide a continuous and adjustable flame for heating, sterilizing, and combustion processes.

Which piece of laboratory glassware delivers precise volumes of liquid during titration and other analytical techniques?

Burette

What is the function of a clay triangle during heating procedures?

It holds crucibles above the Bunsen burner during high-temperature heating.

What tool is used to bore holes in corks or rubber stoppers for inserting glass tubing or thermometers?

Cork borer

What is the function of crucible tongs?

To handle hot crucibles safely during heating and transportation.

Which apparatus is designed specifically for heating substances at very high temperatures?

Crucible with cover

What is the purpose of a deflagrating spoon?

To ignite substances in the flame of a Bunsen burner for qualitative tests.

What is the primary role of a distilling flask?

To hold liquids during distillation processes to separate components based on boiling points.

What laboratory tool holds two burettes securely in place for controlled titration experiments?

Double burette clamp

What apparatus facilitates the precise and controlled dispensing of small volumes of liquids dropwise?

Dropper

Why is an Erlenmeyer flask particularly suitable for reactions involving gas evolution?

It is used for mixing and heating liquids, and its conical design helps contain sloshing and minimize splashing during reactions.

What is the function of an evaporating dish?

It allows controlled evaporation of solvents from solutions to concentrate substances.

Which flask holds liquids and provides even heating during boiling processes?

Florence flask

What laboratory equipment provides a controlled environment for conducting experiments involving hazardous or noxious fumes?

Fume hood

What is the purpose of a glass funnel?

It aids in transferring liquids or fine-grained substances into containers with narrow openings.

Which laboratory glassware measures volumes of liquids with relatively high accuracy?

Graduated cylinder

What apparatus provides an evenly heated flat surface for heating solutions and samples?

Hot plate

What is the function of an iron clamp?

It holds various lab equipment in place on an iron stand.

What supports laboratory apparatus above a lab burner for heating when clamped to a stand?

Iron ring

What provides a stable platform for holding various lab equipment at the desired height?

Iron stand

What apparatus is used to grind and mix chemical substances into fine powders or pastes?

Mortar & pestle

What is the primary function of a pipette?

To measure and transfer precise volumes of liquids.

What tool aids in drawing and releasing liquids into pipettes?

Pipette bulb

What is a separatory funnel used for?

Liquid-liquid extraction, separating immiscible liquids with different densities.

What laboratory tool is used to transfer small amounts of solid substances?

Spatula

What is the purpose of a spot plate?

To provide multiple small wells for performing qualitative tests and reactions on small-scale samples.

What tool holds and grips test tubes securely during heating or transport?

Test tube holder

What piece of glassware facilitates the controlled addition of liquids into a reaction vessel?

Thistle tube

What device measures mass accurately and is equipped with three beams to adjust for different masses?

Triple beam balance

What is a volumetric flask specifically used for?

To prepare solutions with precise and accurate volumes.

How does a volumetric pipette differ from a standard graduated pipette?

It measures and delivers a single specific volume of liquid accurately.

What burner attachment produces a broad and adjustable flame?

Wing top

What is the function of wire gauze when heating glassware over a Bunsen burner?

It provides support for glassware and ensures even heat distribution during heating.

What fundamental scientific law forms the basis of balancing chemical equations?

The Law of Conservation of Mass

According to the Law of Conservation of Mass, what happens to matter in a chemical reaction?

Matter cannot be created nor destroyed, but merely transformed from one form to another.

In the anatomy of a chemical equation, what are coefficients?

Whole numbers placed in front of chemical formulas or elements representing the relative number of moles or molecules.

What do subscripts indicate in a chemical formula?

The number of atoms of that particular element present in a molecule or formula unit.

Why must subscripts never be changed when balancing a chemical equation?

Altering subscripts changes the chemical formula and represents an entirely different compound.

What do superscripts denote in ionic chemical formulas?

The electric charge of ions (e.g., $+1$ in $Na^+$ or $-2$ in $SO_4^{2-}$).

What does the reaction arrow ($\rightarrow$) signify in a chemical equation?

The direction in which the reaction proceeds, from reactants on the left to products on the right.

What physical state does the abbreviation $(aq)$ represent in a chemical equation?

Aqueous, meaning the substance is dissolved in water to form an aqueous solution.

What physical state is denoted by the abbreviation $(s)$ in a chemical equation?

Solid

When beginning to balance a chemical equation, which molecule should generally be balanced first?

The most complex molecule (or elements appearing in the fewest compounds).

In what order are hydrogen ($H$) and oxygen ($O$) balanced relative to other elements?

They are typically balanced last after all other elements have been balanced.

In the balanced equation $C_2H_5OH(l) + 3O_2(g) \rightarrow 2CO_2(g) + 3H_2O(g)$, what does the coefficient $3$ in front of $O_2$ indicate?

Three molecules (or moles) of oxygen gas react with one molecule (or mole) of ethanol liquid.

What is the balanced chemical equation for the reaction of hydrogen gas with oxygen gas to form liquid water?

$$2H_2(g) + O_2(g) \rightarrow 2H_2O(l)$$

What is the balanced equation for the combustion of propane gas ($C_3H_8$) producing carbon dioxide and water?

$$C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(g)$$

What is the balanced equation for the decomposition of ammonium nitrate ($NH_4NO_3$)?

$$2NH_4NO_3(s) \rightarrow 2N_2(g) + 4H_2O(g) + O_2(g)$$

What balanced chemical equation is shown being solved step-by-step on this whiteboard?

$$2Al + Fe_2O_3 \rightarrow Al_2O_3 + 2Fe$$

What is the balanced chemical equation for the reaction of heptane ($C_7H_{16}$) with oxygen gas?

$$C_7H_{16}(l) + 11O_2(g) \rightarrow 7CO_2(g) + 8H_2O(g)$$

What is the balanced equation for the combustion of octane ($C_8H_{18}$) with oxygen gas?

$$2C_8H_{18} + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$$

What is the balanced equation for the reaction between nitrogen gas ($N_2$) and oxygen gas ($O_2$) to form nitrogen dioxide ($NO_2$)?

$$N_2(g) + 2O_2(g) \rightarrow 2NO_2(g)$$

What is the balanced chemical equation for the reaction between lead(II) nitrate and iron(III) chloride?

$$3Pb(NO_3)_2(aq) + 2FeCl_3(aq) \rightarrow 2Fe(NO_3)_3(aq) + 3PbCl_2(s)$$

In the balanced combustion reaction of octane, $2C_8H_{18} + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$, how many total oxygen atoms are present on each side?

$50$ oxygen atoms

In the balanced equation $3Pb(NO_3)_2(aq) + 2FeCl_3(aq) \rightarrow 2Fe(NO_3)_3(aq) + 3PbCl_2(s)$, how many chloride atoms/ions are on each side?

$6$ chloride atoms/ions

What do oxidation numbers (oxidation states) represent in chemistry?

Formal charges assigned to individual atoms within chemical species, reflecting electron distribution and reactivity.

What does a positive change in oxidation number indicate about a chemical species during a redox reaction?

Oxidation, which corresponds to the loss of electrons.

What does a negative change in oxidation number indicate about a chemical species during a redox reaction?

Reduction, which corresponds to the gain of electrons.

What is the oxidation number of an atom in a neutral substance consisting of only one element (e.g., $O_2$, $P_4$, $S_8$, or $Al$ metal)?

$$0$$

What is the oxidation number of a monatomic/simple ion?

It is equal to the electric charge on the ion (e.g., $+1$ for $Na^+$, $-1$ for $Cl^-$).

What is the oxidation number of hydrogen when it is combined with a nonmetal (e.g., in $CH_4$, $NH_3$, $H_2O$, $HCl$)?

$$+1$$

What is the oxidation number of hydrogen when combined with a metal in metal hydrides (e.g., $LiH$, $NaH$, $CaH_2$)?

$$-1$$

What oxidation numbers do Group IA metals and Group IIA elements typically exhibit in compounds?

Group IA metals exhibit $+1$, and Group IIA elements exhibit $+2$.

What is the typical oxidation number of oxygen in compounds, and what is an exception?

Typically $-2$; exceptions occur in molecules and polyatomic ions containing O-O bonds, such as peroxides ($H_2O_2$).

What must the sum of all oxidation numbers equal in a polyatomic ion?

The net charge of the polyatomic ion.

What is the oxidation number of iron ($Fe$) in iron(III) oxide ($Fe_2O_3$)?

$$+3$$

What is the oxidation number of nitrogen ($N$) in the ammonium ion ($NH_4^+$)?

$$-3$$

What is the oxidation number of chromium ($Cr$) in potassium chromate ($K_2CrO_4$)?

$$+6$$

What is the oxidation number of sulfur ($S$) in sulfurous acid ($H_2SO_3$)?

$$+4$$

According to this whiteboard calculation, what is the oxidation state of chlorine in $ClO_3^-$?

$$+5$$

Based on this whiteboard derivation, what is the calculated oxidation number of tin in $SnF_2$?

$$+2$$

How are simple monatomic cations named?

Using the elemental name followed by the word 'ion' (e.g., $Na^+$ is sodium ion).

How are simple monatomic anions named?

By replacing the ending of the element's name with '-ide' (e.g., chlorine becomes chloride ion).

How are transition metal cations with variable oxidation states named?

Using the name of the metal followed by Roman numerals in parentheses indicating the cation charge (e.g., $Fe^{2+}$ is iron(II)).

What are the names of the copper cations $Cu^+$ and $Cu^{2+}$?

$Cu^+$ is Copper(I) and $Cu^{2+}$ is Copper(II).

What is the naming rule for polyatomic oxyanions ending in '-ate' versus '-ite'?

'-ate' is used for the ion with more oxygen atoms, while '-ite' is used for the ion with fewer oxygen atoms.

What are the chemical formulas for the nitrate and nitrite polyatomic ions?

Nitrate is $NO_3^-$, and nitrite is $NO_2^-$.

What are the chemical formulas for the sulfate and sulfite polyatomic ions?

Sulfate is $SO_4^{2-}$, and sulfite is $SO_3^{2-}$.

What is the systematic rule for naming binary acids (hydracids)?

Begin with the prefix 'hydro-', followed by the root name of the second element modified with '-ic', and end with the word 'acid'.

What are the names of the binary acids $HCl$, $HBr$, $HI$, and $HF$?

Hydrochloric acid, hydrobromic acid, hydroiodic acid, and hydrofluoric acid.

How does the suffix of an oxyacid change based on the polyatomic anion's name?

If the anion ends in '-ate', change the ending to '-ic acid'; if the anion ends in '-ite', change the ending to '-ous acid'.

What are the names of the oxyacids $H_2SO_4$ and $H_2SO_3$?

$H_2SO_4$ is sulfuric acid, and $H_2SO_3$ is sulfurous acid.

What is the name of the oxyacid with formula $HClO_2$?

Chlorous acid

How are inorganic base compounds containing the $OH^-$ ion named?

By stating the name of the metal or cation followed by 'hydroxide' (e.g., $NaOH$ is sodium hydroxide).

What Greek prefixes denote 1, 2, 3, 4, and 5 atoms in covalent compound nomenclature?

Mono- ($1$), Di- ($2$), Tri- ($3$), Tetra- ($4$), and Penta- ($5$).

What Greek prefixes denote 6, 7, 8, 9, and 10 atoms in covalent compound nomenclature?

Hexa- ($6$), Hepta- ($7$), Octa- ($8$), Nona- ($9$), and Deca- ($10$).

What is the covalent name for the molecule $N_2O$?

Dinitrogen monoxide

What are the common names for the ions $C_2O_4^{2-}$, $CN^-$, and $Cr_2O_7^{2-}$?

Oxalate ($C_2O_4^{2-}$), cyanide ($CN^-$), and dichromate ($Cr_2O_7^{2-}$).

What are the two primary methods used to balance redox equations?

The oxidation number method (oxidation state method) and the half-reaction method (ion-electron method).

What two conservation laws must be satisfied when balancing redox reactions?

The Law of Conservation of Mass and the Law of Conservation of Charge.

In the half-reaction method in an acidic medium, how are oxygen and hydrogen atoms balanced?

Add $H_2O$ to balance oxygen atoms and $H^+$ to balance hydrogen atoms.

What extra step is required when balancing a redox reaction in basic solution using the half-reaction method?

Add $OH^-$ ions to both sides to neutralize $H^+$ into $H_2O$, then simplify and cancel excess $H_2O$.

What is the balanced redox equation for the reaction between iron(II) and permanganate ion in acidic solution (Example 1)?

$$5Fe^{2+} + MnO_4^- + 8H^+ \rightarrow 5Fe^{3+} + Mn^{2+} + 4H_2O$$

In the reaction between nitric acid and arsenous acid (Example 2), which element is reduced and which is oxidized?

Nitrogen in $HNO_3$ is reduced (from $+5$ to $+2$), and arsenic in $H_3AsO_3$ is oxidized (from $+3$ to $+5$).

What is the simplified balanced redox equation for copper metal reacting with nitrate ions in acidic solution (Example 3)?

$$Cu(s) + 2NO_3^-(aq) + 4H^+(aq) \rightarrow Cu^{2+}(aq) + 2NO_2(g) + 2H_2O(l)$$