ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE REVIEW Questions related to chemistry test your knowledge of chemical properties and processes. You may be asked questions about states of matter, properties of matter, phase changes, chemical bonds, chemical solutions, chemical reactions, and acids and bases. You may be asked to CHEMISTRY balance chemical equations. Let’s get started in understanding how chemistry is important on the ATI TEAS. ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE – CHEMISTRY UNDERSTANDING STATES OF MATTER UNDERSTANDING STATES OF MATTER Matter is made up of microscopic particles that move different speeds Lower temperatures result in a liquid , in which molecules cohere but depending on the energy they are exposed to. We measure this energy are fluid. Coherence means that the molecules remain close together, as temperature. The molecules can move either quickly and randomly but they can change position by sliding over one another. In liquids, or hardly at all. molecules move less freely than in a gaseous state, sliding past one another. They have a fixed volume but will flow freely unless they fill a When the energy is high, matter take the form of a gas , in which portion of a container. molecules are moving about quickly and are far apart. Gases have no fixed form. Molecules are free to move at random past each other, and When the temperature is low, matter takes the form of a solid , in which they tend to fill any container that holds them. If a gas is not contained, molecules are packed closely together and retain their positions. Solid its molecules will disperse. matter is rigid, and molecules retain a uniform spacing. A solid has a PHOTO CREDIT: LIVE SCIENCE PHOTO CREDIT: LIVE SCIENCE defined form, which is brittle. It can be broken into pieces but tends to stay together. A somewhat unusual state of matter is plasma , which is like a gas in many of its properties but carries an electric charge. The TEAS focus on solids, liquids, and gases. ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE – CHEMISTRY UNDERSTANDING CHANGES IN STATE OF MATTER UNDERSTANDING PROPERTIES OF MATTER The state of matter depends on temperature and pressure. Higher All types of matter can be described in terms of the physical temperatures cause molecules to energize and move farther apart. and chemical properties each substance has. Physical Increasing pressure forces molecules closer together. Melting is the properties are observable and there is an extensive list of phase change from solid to liquid and boiling is the phase change from physical properties that one could observe about a substance. liquid to gas. There is also a direct change from solid to gas known as A few examples are density, the temperatures at which the sublimation . The phase change from gas to liquid is condensation and substance undergoes phase changes, malleability, the change from liquid to solid is freezing . A direct change from gas to conductivity, specific heat capacity, mass, volume, color, and solid is deposition . many other properties. Physical properties are further divided PHOTO CREDIT: THOUGHTCO into intensive and extensive properties. An intensive property does not depend on the size or amount of matter in the object, while an extensive property does depend on the amount of matter in the object. For example, mass is PHOTO CREDIT: VECTORSTOCK extensive because the measurement would change the size of the sample. Boiling point is intensive because the temperature at which the object boils is not dependent on its volume.
ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE – CHEMISTRY UNDERSTANDING PROPERTIES OF MATTER UNDERSTANDING PROPERTIES OF MATTER Water is a polar inorganic compound that is transparent and The polarity of water allows it to exhibit both cohesive and nearly colorless. H2O is a covalent compound because oxygen adhesive properties. Cohesiveness allows water to travel and hydrogen are nonmetals. It has 8 total valence electrons through tiny capillaries and creates surface tension on the (6 from oxygen and 1 from each hydrogen). Breaking the surface of a body of water. Adhesiveness allows water to stick bonds requires a lot of energy, so water has a very high to other molecules and dissolve them, making it known as the specific heat and heat of vaporization. The molar mass of “universal solvent.” water is 18.02 g/mol. It commonly exists as solid, liquid, and PHOTO CREDIT: BIONINJA gas. PHOTO CREDIT: SLIDESHARE ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE – CHEMISTRY UNDERSTANDING PROPERTIES OF MATTER UNDERSTANDING CHEMICAL BONDS Water also has a unique property called osmosis, which is a A chemical compound is created when two or more atoms specific type of diffusion. Diffusion is a term used to describe join to form a chemical bond that leaves the atoms in a less the process of a substance moving from an area of high excited state than they were in before the bond. Such bonds concentration to an area of low concentration. Osmosis is a form in two ways. type of diffusion in which water moves passively through a semi-permeable membrane to equalize water concentration on both sides of the membrane. This is how water moves through cell walls in the body. PHOTO CREDIT: BYJU PHOTO CREDIT: SHUTTERSTOCK ATI TEAS SCIENCE – CHEMISTRY ATI TEAS SCIENCE – CHEMISTRY UNDERSTANDING CHEMICAL BONDS UNDERSTANDING CHEMICAL BONDS A covalent bond occurs when atoms share electrons between them. This type of bond is An ionic bond is created between atoms when one atom gives an electron to the other. common between two atoms of the same element, as in hydrogen (H2) or in similar These bonds typically take place between metals and nonmetals due to the unique elements. When a molecule shares a pair of electrons in a stable state, it has formed a electron configuration of metals, with the metal giving an electron to the nonmetal. This covalent bond. Alkanes, for example, share a single bond. In some compounds, one atom transfer creates a positive charge and a negative charge at the ends of the compound. takes the shared electron for more time, due to its structure, forming a polar covalent The positive charge, or cation , is created by the giver of an electron. The negative charge, bond . This molecule is partly negatively charged and partly positively charged. Some or anion , is located at the receiving end of the electron. The net charge of the molecules form a double bond , sharing four electrons as opposed to two. These bonds compounds remains balanced at zero. are commonly represented in the alkenes, hydrocarbons with twice as many hydrogen molecules as carbon molecules. It is possible to form triple bonds as seen in a group of hydrocarbons called alkynes. PHOTO CREDIT: WIKIBOOKS PHOTO CREDIT: QUORA PHOTO CREDIT: BRITANNICA
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