Chemistry Stoichiometry and The Mole

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Questions and Answers

How does the Law of Conservation of Matter apply to balancing chemical equations?

The number and type of atoms must stay the same. (correct)

Atoms are created during the reaction.

Coefficients are not needed for balancing.

Only the products matter in balancing.

How many moles of cream of tartar are in 4.0 grams?

0.045 moles

0.015 moles

0.032 moles

0.021 moles (correct)

What is the molar mass of Gold, Au?

206.4 g

158.9 g

197.0 g (correct)

175.3 g

If you have 15 slices of bread, 10 pieces of cheese, and various other ingredients, which ingredient limits the number of club sandwiches?

Slices of turkey Signup and view all the answers

How many molecules are in 12.6 grams of fructose, C6H12O6?

4.21 x 10^22 molecules Signup and view all the answers

How many grams of CO2 are produced from 2250 grams of iron (III) oxide, Fe2O3?

1,856 g CO2 Signup and view all the answers

When balancing the equation 2 HCl + Zn → H2 + ZnCl2, how many moles of Zn are used?

1 mole Zn Signup and view all the answers

If 6 moles of Fe are produced in the reaction, how many moles of CO are required?

9 moles CO Signup and view all the answers

What is the theoretical yield of sulfur trioxide produced from the reaction of 6.4 grams of sulfur dioxide and 4.0 grams of oxygen gas?

8.0 g SO3 Signup and view all the answers

Which ionic substance mentioned is insoluble in water?

CaCO3 Signup and view all the answers

When Sr(NO3)2 and K2SO4 are mixed, what is the formula of the solid precipitate formed?

SrSO4 Signup and view all the answers

What describes the solution when 40g of KCl are dissolved in 100g of water at 60°C?

Unsaturated solution Signup and view all the answers

Why do carbonated beverages fizz upon opening?

Gas solubility decreases as pressure decreases. Signup and view all the answers

Why is it beneficial to apply heat when making a syrup with sugar and water?

Increasing temperature allows more sugar to dissolve in water. Signup and view all the answers

What happens to nitrogen in the blood when a scuba diver ascends too quickly?

It forms bubbles due to decreased pressure. Signup and view all the answers

Under what conditions can a supersaturated solution form?

When a solution at elevated temperature cools slowly. Signup and view all the answers

What is the main purpose of adding flocculants during water treatment?

To remove suspended particles Signup and view all the answers

Which of the following methods utilizes pressure to purify water?

Reverse osmosis Signup and view all the answers

What is the primary function of disinfection in water treatment?

To kill harmful microorganisms Signup and view all the answers

During the distillation process, what occurs after water vapor is produced?

It is condensed into a liquid Signup and view all the answers

Which of the following actions can help reduce contaminants in drinking water at home?

Flushing the tap for two minutes Signup and view all the answers

What is the correct neutralization reaction between sulfuric acid and sodium hydroxide?

H2SO4 (aq) + 2NaOH (aq) → 2H2O (l) + Na2SO4 (aq) Signup and view all the answers

How does a strong acid differ from a weak acid in terms of dissociation?

Weak acids have a low concentration of H3O+ at equilibrium Signup and view all the answers

What does a pH of 7 indicate about the concentration of H3O+ and OH- in a solution?

H3O+ = OH- Signup and view all the answers

Which type of vitamins needs to be replenished more often?

Water-soluble vitamins Signup and view all the answers

What is the structural role of cellulose in plants?

Structural component Signup and view all the answers

Which functional group is formed when amino acids create a peptide bond?

Amide Signup and view all the answers

Which molecule is primarily responsible for energy storage in the human body?

Glycogen Signup and view all the answers

Why are saturated fats able to pack more tightly than unsaturated fats?

They lack double bonds Signup and view all the answers

Which of the following statements about vitamins is true?

Some vitamins are better absorbed from food sources Signup and view all the answers

What distinguishes blood type A from blood type B?

Presence of A oligosaccharide Signup and view all the answers

What type of biomolecules are triglycerides categorized under?

Fats Signup and view all the answers

What is the relationship between hydrogen ion concentration and pH?

A lower pH indicates a higher hydrogen ion concentration. Signup and view all the answers

Which of the following accurately describes hydrocarbons?

Hydrocarbons contain only carbon and hydrogen. Signup and view all the answers

What is a significant consequence of hydrogenating vegetable oils?

Formation of trans fatty acids. Signup and view all the answers

What defines organic chemistry?

The study of carbon-containing molecules. Signup and view all the answers

Which vitamins are classified as fat-soluble vitamins?

A, D, E, and K. Signup and view all the answers

What is the balanced combustion reaction of pentane?

C5H12 + 8O2 → 5CO2 + 6H2O Signup and view all the answers

What defines the difference between cis and trans isomers in organic compounds?

The orientation of functional groups around a double bond. Signup and view all the answers

Why do alkenes undergo hydrogenation?

To change the consistency of the fats. Signup and view all the answers

What role does HDL cholesterol play in the body?

It removes cholesterol from arteries, keeping blood vessels clear. Signup and view all the answers

Which statement accurately describes the orientation of phospholipids in a cell membrane?

The nonpolar fatty acids are buried within the bilayer. Signup and view all the answers

What is one of the key functions of cholesterol in the body?

It is a structural component of cell membranes. Signup and view all the answers

Which of the following is NOT a function of proteins in the human body?

Storing genetic information. Signup and view all the answers

What type of bond provides strong stabilization between certain amino acid side chains?

Covalent bonds between cysteine side chains. Signup and view all the answers

Why is it vital to maintain the correct balance of energy nutrients in the body?

To optimize energy production and utilization during physical activity. Signup and view all the answers

Which intermolecular forces contribute to the stabilization of protein structures?

Hydrogen bonds, London dispersion forces, and ion-dipole interactions. Signup and view all the answers

What happens to fatty acids during prolonged, strenuous exercise?

They are mobilized to spare glucose and oxidized for energy. Signup and view all the answers

Study Notes

Part 1 - The Mole, Stoichiometry

The Law of Conservation of Matter states that the total number and type of atoms in reactants equals the total number and type of atoms in products. Coefficients balance chemical equations to demonstrate this.
Equations are balanced to ensure conservation of matter—rearranging atoms, not losing or gaining them.
Examples of balanced equations (with substances) are provided.
The number of items represented by different units is outlined:
- 1 pair = 2 items
- 1 dozen = 12 items
- 1 mole = 6.02 x 10²³ items
Molar mass is the mass (in grams) of one mole of a substance.
Key molar masses (with substances) are given.
Molecular/formula units are used to represent one mole.
Sample calculations are shown to determine the number of molecules in 12.6 grams of fructose (C₆H₁₂O₆).
Also sample calculations are shown demonstrate determining the number of moles of cream of tartar (KC₄H₅O₆) in 4.0g

Part 2 - Properties of Solutions

Solubility rules are used to predict whether ionic compounds dissolve in water (some are soluble, some are insoluble).
An example of a balanced equation and the precipitate are provided when combining Sr(NO₃)2 and K₂SO₄.
Solubility depends on temperature - as shown in a given graph.
Unsaturated, saturated, and supersaturated solutions are explained in context with the graph, and given an example.
At 60°C, dissolving 40g of KC_l in 100g water is an unsaturated solution.

Part 3 - Water – Properties and Quality Issues

Water's high boiling point is due to the strong hydrogen bonds between water molecules.
High surface tension is caused by the hydrogen bonding at the surface of water.
Ice—Solid water—is less dense than liquid water due to crystal lattice structure.
Water is a universal solvent due to its polarity.
Water sources and treatment processes are described- including: Groundwater, local lakes, local rivers and coagulation, filtration, disinfection, aeration, fluoride addition, and anticorrosion control.
Reverse osmosis to purify water purifies water by applying pressure greater than osmotic pressure and forcing water to cross a membrane to purify water.
Distillation purifies water by heating impure water to create vapor, then cooling the vapor to produce liquid pure water.

Part 4 - Acids and Bases

Definitions of acids and bases (Arrhenius, Brønsted-Lowry, Lewis) are mentioned in a table format.
Neutralization reaction between H₂SO₄ and NaOH is presented. The acid, base, and salt are identified.
Comparing the hydrogen ion concentrations of solutions at different pH (e.g., at pH 1 vs. pH 2) is demonstrated, and symbols used like (>, <, =).

Part 5 - Intro to Organic Chemistry

"Organic" means carbon-containing molecules.
Carbon-based compounds have structural diversity due to types of carbon-carbon bonds (single, double, triple) and cyclic structures.
Hydrocarbons have carbon and hydrogen only. Ethane (saturated), ethylene (unsaturated) and acetylene (unsaturated) are examples of hydrocarbons given with formulas/structures.
Combustion of hydrocarbons (like pentane, C₅H₁₂) is a significant chemical reaction.
Alkenes (unsaturated hydrocarbons) participate in addition reactions (like hydrogenation).
Hydrogenation and isomers (cis and trans) are described in detail.
Identification of functional groups in organic molecules (carboxylic acid, ether, alcohol, ketone, amine, amide, ester, alkyl halide) are presented.
Formula and molar mass calculations are shown for certain organic molecules.

Part 6 - Biomolecules

Fat-soluble vitamins (A, D, E, and K) and water-soluble vitamins (C and B vitamins are listed, along with basic properties).
Properties the vitamins have in common are shared.
Importance of vitamins for cellular reactions.
Functional groups in important biomolecules are described, including carbohydrates (monosaccharides, cyclic form—ether and alcohol), amino acids (carboxylic acid and amine), and triglycerides (ester).
Types of functional groups formed when amino acids join (amide group) are identified.
The roles of starch and cellulose (energy storage and structural support) are discussed.

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Description

Explore the fundamental concepts of stoichiometry and the mole in this quiz. Understand the Law of Conservation of Matter, the significance of balanced chemical equations, and the calculations for molar mass and moles. Test your knowledge with examples and sample calculations related to different substances.