The TExES Chemistry 7 – 12 Exam is a certification examination that is designed to determine whether or not an individual has the knowledge necessary to teach chemistry at the high school level in the Texas public school system. This exam covers topics similar to those found specifically in the chemistry portion of the Physical Science 7 – 12 exam and as such it assesses an individual’s knowledge of a variety of topics related to chemistry such as chemical reactions, energy, matter, and other similar topics and teaching methods that can be used to effectively teach these topics. This exam may be required, in addition to or instead of the Physical Science 7 – 12 Exam and/or the Science 7 – 12 Exam, in order to become a certified high school chemistry teacher in the state of Texas depending on the exact type of teaching position the individual is pursuing. The exam usually consists of 100 multiple-choice questions that are related to the following areas:
- Scientific Inquiry and Processes (24%)
- Matter and Energy (41%)
- Chemical Reactions (23%)
- Science Learning, Instruction and Assessment (12%)
The exam-taker will be supplied with a Formula and Definitions Reference Sheet, a copy of the periodic table, and a scientific calculator for the exam. The exam-taker will have five hours to complete the exam and the exam will be scored on a scale of 100 – 300 with 240 set as the minimum score considered as passing for the exam. The registration fee for the Chemistry 7 – 12 Exam is $131 and the exam is administered in a computer-based format. However, there are usually other exams and fees that are required in addition to this exam in order to become certified as an entry-level high school teacher within the state of Texas.
240 TExES Chemistry 7 – 12 Exam Practice Questions
Sample Study Notes
1. Define the term science.
The American Heritage College Dictionary defines science as “the observation, identification, description, experimental investigation and theoretical explanation of phenomena.” Its Latin root is scientia, which means “knowledge.”
- NATURAL SCIENCE is concerned with the natural world; SOCIAL SCIENCE studies human behavior. Both are based on empirical evidence, which is observable data that can be verified by other scientists who are working in similar situations under the same conditions.
- FORMAL SCIENCE is the systematic study of a specific area; it is essential to developing the hypotheses, theories and laws used in other scientific disciplines, i.e. describing how things work (natural science), how people think, and why they do what they do individually and as a society (social sciences). It is based on a priori evidence, which proceeds from a theory or assumption rather than from observable phenomena.
- APPLIED SCIENCE is using scientific research in any of the natural, social and formal sciences to address human needs.
2. Define scientific method, scientific inquiry, deductive and inductive reasoning.
- SCIENTIFIC METHOD: a set of procedures used to study natural phenomena. It provides guidelines with which to pose questions, analyze data and reach conclusions. It is used to investigate an event, gain knowledge or correct earlier conclusions about the occurrence and integrate the new information with previously learned data. Researchers pose hypotheses, and design experiments and studies to test them. The process must be objective, documented and shared with other researchers so the results can be verified by replicating the study in similar situations under the same conditions.
- SCIENTIFIC INQUIRY: used to explore theories and develop explanations for natural phenomena. It has two functions: to provide a description of how something happens and to explain why the process succeeds or fails.
- DEDUCTIVE REASONING: a process in which a specific conclusion logically follows from a general premise. If the premise is true, the conclusion is true. Deductive reasoning is used in mathematics.
- INDUCTIVE REASONING: a process in which a universal conclusion is formed from considering an individual example. Inductive reasoning is the methodology of the natural and social sciences.
3. Describe the steps used in the scientific method.
The steps of the scientific method described here are not necessarily used in exactly the same way in all sciences. Sometimes they happen at the same time or in a different order and may be repeated during the course of the study. Whatever order researchers use, the steps should be applied with intelligence, imagination and creativity. The following sequence is the one used most of the time.
1. A question is asked about a natural phenomenon. It should be stated in specific language to focus the inquiry.
2. The subject is thoroughly researched. Previous test results are studied. It is important to understand what the earlier experiment(s) proved or disproved.
3. With information gleaned from researching the topic, a hypothesis is formed about a cause or effect of the event, or its relationship to other occurrences.
4. An experiment is designed and conducted to test the hypothesis and gather information.
5. The resulting data is analyzed to determine if they support or refute the hypothesis.
It is common for test results to lead to more questions about the subject or a related phenomenon.
4. Describe chemistry and define its various disciplines.
Chemistry grew out of the practice known as alchemy, a philosophical and spiritual discipline that investigated the possibility of transforming base metals into gold. Modern chemistry is the physical science concerned with the composition, structure, properties and reactions of atoms, molecules, crystals and other aggregate matter. It is sometimes called the “central science” because it connects the other natural sciences. Chemistry studies matter in relation to energy (the capacity to do work), entropy (the measurement of energy unable to do work) and the spontaneity of chemical reactions (the changing of matter into one or more substances). Chemistry is divided into several disciplines based on the type of matter being studied:
- ORGANIC CHEMISTRY is the study of compounds that contain carbon. Note: some carbon compounds are considered inorganic compounds.
- INORGANIC CHEMISTRY is the study of mineral compounds.
- BIOCHEMISTRY is the study of organisms capable of responding to stimuli, reproduction and growth.
- PHYSICAL CHEMISTRY is the study of energy systems at the macro, molecular and sub-molecular levels.
- ANALYTICAL CHEMISTRY is the study of matter and its chemical composition and structure.
5. Define these chemical terms: matter, atom, proton, neutron, element, compound, and molecule.
- MATTER: any substance that has mass and takes up space
- ATOM: small particle with a positively-charged core made of protons, neutrons and electrons
- NUCLEUS: the positively-charged center of an atom
- PROTON: subatomic particle with a positive electric charge that forms part of the nucleus
- NEUTRON: subatomic particle that is neutral (has no electric charge), and which forms part of the nucleus
- ELECTRON: subatomic particle that has a negative electric charge, and which circles the nucleus.
- ELEMENT: made of only one atom; cannot be broken down further. All the elements are grouped by their atomic number on the Periodic Table.
- COMPOUND: two or more elements joined together with a specific ratio of atoms that determines structure, and a particular system that determines chemical properties
- MOLECULE: smallest part of a piece of matter that contains all of the matter’s particular properties. Organisms, cytoplasm and cell membranes are made of molecules.
6. Describe matter.
Matter is any substance that has mass and takes up space. It is all the physical items in the universe: dirt, air, water, chairs, pencils, parsnips, pumpkins, and everything else. Matter is composed of atoms (small particles with a positively charged core made of protons, neutrons and electrons) and molecules (the smallest part of an element that contains all of its particular properties). Elements have only one atom and cannot be broken down further. One hundred and nine elements have been identified so far. Elements combine to form compounds, which have a specific ratio of atoms. This determines structure and defines the chemical properties of the substance. The four fundamental states of matter are:
- SOLID: molecules packed tightly together with a definite shape and volume
- LIQUID: molecules have the ability to move and do not disperse readily
- GAS: molecules move very quickly, have low density and are distributed uniformly
- PLASMA: the substance that contains proteins, fats and other molecules suspended in water; it makes up the living matter of plant and animal cells
7. Explain energy.
Energy is the capacity to do work or cause change. It is always associated with movement, whether at the molecular, atomic, or subatomic level. Its companion is entropy, which is the measurement of energy unable to do work. Energy can change forms but it cannot be created or destroyed. It is a closed system that remains constant. This principle of physics is known as the Law of Conservation of Energy. There are many forms of energy: light (electromagnetic radiation within a specific wavelength), heat (movement of atoms or molecules), electric (attraction and repulsion of electrons and protons), mechanical (related, produced or dominated by physical force) and nuclear (the charged center of an atom) to name the most common. There are two types of energy: potential, which is energy that is stored and waiting to be used; and kinetic, which is energy that is currently being used. Scientists are not sure what dark energy is. It appears to be some sort of anti-gravity that is pushing the galaxies apart. More study is needed to explain this force and its function in the universe.
8. Describe a chemical reaction.
A chemical reaction is a process that changes one substance into another substance (the product) with an altogether different structure and composition. There is a rearrangement of the bonds (strong electrical force) that hold the atoms together; however, the total mass and number of atoms equals the sum of all the reactants, i.e. the original materials. Energy is always either consumed or liberated. The chemical reaction rate measures the amount of product produced or consumed. It depends on the reactants involved, the surface area available for contact, the type of chemical change, the temperature and pressure applied, and the kind of catalyst used. Some common chemical reactions and their components:
- RUST: iron in steel reacts with oxygen in the atmosphere
- PHOTOGRAPHIC FILM: light hits a cellulose derivative coated with photosensitive emulsion
- HOMEMADE VOLCANO: baking soda and vinegar mix and carbon dioxide is released
- BROWN FRUIT: meat of the fruit reacts to the oxygen in the air
9. List and define the six types of chemical reactions.
All chemical reactions fall into one of the following categories:
- COMBUSTION: oxygen combines with another compound to form water and carbon dioxide; it is an exothermic process because heat and light are produced.
- SYNTHESIS: two or more simple compounds combine and form a more complicated, totally different substance.
- DECOMPOSITION: a complex compound breaks down into simpler substances, which sometimes disintegrate; this process is the opposite of synthesis.
- SINGLE DISPLACEMENT: one element trades places with another in the same compound.
- DOUBLE DISPLACEMENT: the anions (ion with a negative electrical charge) and cations (ion or atom with a positive electrical charge) of different molecules switch places and form two totally different compounds.
- ACID-BASE: a double displacement occurs when an acid and a base (alkaline substance) react and produce water.
10. Discuss the National Assessment of Educational Progress requirements for assessments in science.
The study of science is divided into three major areas: earth, physical and life sciences. Each of these is sub-divided into specialized fields of study. The U.S. Department of Education established criteria for testing comprehension of science concepts, using recommendations from the National Assessment of Educational Progress. Students are required not only to know facts, but to integrate those facts into previously-learned information by using critical thinking. In other words, students need to be able to apply the facts they learn in class to phenomena found in the real world. The assessments developed by educators, curriculum specialists and the business community emphasize the importance of assessing students’ ability to reason, understand concepts, solve problems, evaluate results, and communicate knowledge of the subject matter. The tests attempt to measure whether students can take cognitive skills learned in science, apply them in other disciplines, and use them outside of school in meaningful ways.