Notes, summaries, assignments, exams, and problems for Chemistry

Mixture

A mixture is a physical blend of two or more components.

Heterogeneous mixture

A mixture in which the composition is not uniform throughout is a heterogeneous mixture.

Homogeneous mixture

A homogeneous mixture is a mixture in which the composition is uniform throughout. Another name of homogeneous mixture is a solution.

Phase

The term phase is used to describe any part of a sample with a uniform composition and properties.

Filtration

The process that separates a solid from the liquid in a heterogeneous mixture is called filtration.

Distillation

One way to separate water from the other components in tap water is through a process called distillation.

Properties of Matter

Mass

The matter of an object is a measure of the amount of matter the object... Continue reading "Understanding Mixtures, Phases, and Chemical Reactions" »

Fundamental Concepts in Physical Science

I. Atomic and Chemical Structure

Basic Constituents of Matter

Atom

The basic or fundamental constituent of matter.

Element

A species of atoms having the same number of protons in their atomic nuclei.

Molecule

An electrically neutral group of two or more atoms of the same element held together by chemical bonds.

Compound

An electrically neutral group of two or more atoms of different elements held together by chemical bonds.

Ion

An atom or molecule in which the number of electrons is not equal to the number of protons. (Note: Extracting electrons can lead to plasma.)

Isotope

An element made up of atoms that have the same number of protons (atomic number) but a different number of neutrons (mass number).

Periodic Table

English Culinary Terms

Preparation and Mixing Methods

• Beat: To use a spoon, fork, whisk, or electric mixer to mix ingredients together, using a fast circular movement (batir).
• Blend: To combine two or more ingredients until the mixture is smooth and uniform in texture, color, and flavor (barrejar).
• Bread: To coat a food in bread crumbs before frying or baking (rebozar).
• Chill: To put food in the refrigerator for at least two hours (refredar).
• Chop: To cut into little pieces (trocear).
• Dice: To cut into small square pieces (cortar a cuadrados).
• Drain: To remove all liquid – may be done in a strainer or by pressing a plate against the food while tilting the container forward (quitar líquido).
• Grate: To scrape against the small holes of a grater, making

Diamond Properties and Production: Comprehension Check

Maximum Score: 7 points

1. True or False Statements (2 points)

Determine if the following statements are TRUE or FALSE. Copy the evidence directly from the source text. No marks are awarded for only stating TRUE or FALSE.

1. The structure of man-grown diamonds is completely different from that of natural diamonds.

   FALSE: Optically, chemically, and physically they're identical to a mine diamond.

2. Gemesis diamonds are cheaper than those found in mines.

   TRUE: As regards price, a one-carat yellow diamond from nature costs about $20,000 and a man-made one costs about $6,000.

2. Answering Questions in Your Own Words (2 points)

Based on the ideas in the text, answer the following questions in your own words.... Continue reading "Diamond Properties and Synthetic Production Quiz" »

Rutherford Experiment

The results of the gold foil experiment led to the discovery of a very densely packed bundle of matter with a positive electric charge. Rutherford called this positive bundle of matter the nucleus. He was trying to figure something else out and accidentally discovered this. As much of a discovery as the gold foil experiment was, it wasn’t discovered intentionally.

Atomic Number

Consists of the number of electrons or protons.

Mass Number

Consists of the protons added to the neutrons.

Nonpolar Covalent Bond

A covalent bond in which the bonding electrons are shared equally by the bonded atoms. Example: H-H

Polar Covalent Bond

A covalent bond in which the bonded atoms have an unequal attraction for the shared electrons. Example:... Continue reading "Introduction to Atomic Structure and Chemical Bonding" »

From Dalton to the Electron

The simple model set by Dalton needed updating. In 1894, Crookes discovered that cathode rays were produced just by applying a very high voltage between two electrodes. He observed that he could get a shadow, so his conclusion was that "some particles exit from the metal plate placed in the cathode." As those particles were attracted by the positive electrode, the so-called cathode rays had to have a negative charge. Thomson (1897) interpreted the experiment as showing that cathode rays were a stream of electrons. Atoms, as introduced by Dalton, were not indivisible. Since electrons were issued from a metal, atoms were made of electrons (negative charge) and something else with a positive charge because matter is... Continue reading "Atomic Structure: From Dalton to Rutherford" »

This document outlines fundamental laws, key concepts, and various types of chemical reactions crucial for understanding the principles of chemistry. Each point provides a concise definition, serving as a quick reference for core chemical knowledge.

Fundamental Chemical Laws and Concepts

1. Law of Conservation of Mass

   Mass is neither created nor destroyed in a chemical reaction; it remains constant.

2. Law of Definite Proportions

   A compound always contains the same elements in the same proportion by mass.

3. Law of Multiple Proportions

   Elements combine in small, whole-number ratios to form different compounds.

4. Gay-Lussac's Law of Gaseous Volumes

   The volumes of reacting gases (at constant temperature and pressure) are in simple whole-number ratios.

5. Newlands' Law

1- Explain the process of making monomers and polymers.

Monomers are small subunits that when bound together form polymers

Polymers are formed by either dehydration or by hydrolysis

2- Define Cytoskeleton with its characteristics.

Structural framework consist of protein tubules, filaments: Microtubules, Microfilaments, Intermediate filaments

3- What is another name for protein channel that link cells?

Adhesion proteins – permit cell to stick together

4- What are the characteristics of phospholipids

Each phospholipid contains head and tail (head is hydrophilic, means it is attracted to water; the tails is hydrophobic, repels water)

5- What is the primary component of a cell membrane made of?

Phospholipids (glycerol bond, 2 fatty acids, phosphate group)... Continue reading "General Biology Test: Questions and Answers" »