Chem Final Flashcards
Define chemistry
A science that deals with the composition, structure, and properties of substances and with the changes
Define matter
Anything that takes up space and can be weighed
Identify the 3 states of matter and describe the general characteristics of each
Solid, liquid, and gas. Solids have a definite shape and volume. Liquids have a definite volume, but take the shape of the container. Gases have no definite shape or volume
Tell the difference between an element and a compound
Elements are pure substances which are composed of only one type of atom. Compound are substances which are formed by two or more different types of elements that are united chemically in fixed proportions. There are nearly 118 elements (at present) of which nearly 94 occur naturally on Earth
Identify if a physical or chemical change has occurred
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed
Write numbers in scientific notation
A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10. For example, 650,000,000 can be written in scientific notation as 6.5 ✕ 10^8
Give examples of units for length, mass, temperature, and time
The SI units for length, mass, time, and temperature are metre, kilogram, second, and Kelvin respectively. These units are defined based on fundamental constants and ensure consistency and accuracy in scientific measurements
Describe how to do dimensional analysis unit conversion
Performing dimensional analysis begins with finding the appropriate conversion factors. Then, you simply multiply the values together such that the units cancel by having equal units in the numerator and the denominator
Read and write chemical formula
For example, the molecular formula for acetic acid, the component that gives vinegar its sharp taste, is C2H4O2. This formula indicates that a molecule of acetic acid (Figure 3.3. 6) contains two carbon atoms, four hydrogen atoms, and two oxygen atoms. The ratio of atoms is 2:4:2
List the 3 subatomic particles and their properties (charge and relative mass)
Electrons are negatively charged particles and its mass is 1/1840 the mass of a hydrogen atom. Protons are positively charged particles. Each proton has a mass about 1840 times that of an electron. Neutrons are subatomic particles with no charge but with a mass nearly equal to that of a proton.
Discuss where each of the 3 subatomic particles are located in an atom
Atoms are made up of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus
Discuss the difference between the atomic number and mass number
The major difference between atomic number and mass number is that the atomic number states the number of protons present in an atom whereas, the mass number indicates the total number of protons and the number of neutrons present in an atom
Define an isotope and interpret an isotope symbol
Isotopes are atoms of the same element that have the same number of protons (i.e., atomic number, “Z”) but a different number of neutrons, meaning that their mass number, “A”, varies. Take hydrogen, for example. It has three naturally occurring isotopes–1H, 2H, and 3H
Identify the groups/families of the periodic table
Families of the Periodic Table. On the periodic table, there are families which are groups of elements with similar properties. These families are alkali metals, alkaline earth metals, transition metals, post-transition metals, metalloids, halogens, noble metals, and noble gases
Identify an element as metal, nonmetal, or metalloid
Elements to the left of the line are considered metals. Elements just to the right of the line exhibit properties of both metals and nonmetals and are termed metalloids or semimetals. Elements to the far right of the periodic table are nonmetals. The exception is hydrogen (H), the first element on the periodic table
List some properties of metals and nonmetals
Metals are defined as elements that possess properties such as , malleability, ductility, sonorous and good conductors of heat and electricity. While nonmetals are those elements that are not malleable, ductile, sonorous and are poor conductors of heat and electricity
Define ion, cation, & anion
Cations are ions that are positively charged. Anions are ions that are negatively charged. Ions are charged atoms or molecules. If a balanced atom loses one or more electrons, it will become a positively charged cation. If a balanced atom gains one or more electrons, it will become a negatively charged anion
Describe how cations and anions are formed (what do we change the number of
Ions are charged atoms or molecules. If a balanced atom loses one or more electrons, it will become a positively charged cation. If a balanced atom gains one or more electrons, it will become a negatively charged anion
Identify the different types of radioactive decay (alpha, beta, gamma ray, positron, electron capture)
Alpha and beta decays almost always leave the nucleus in an excited state. Gamma emission brings the nucleus down to a more stable energetic state. Alpha and beta decays are often difficult to occur. They can be very slow processes.
Fill in the blanks of a nuclear equation
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Describe what must occur for an unstable nucleus to become more stable
The unstable nucleus of radioactive atoms emit radiation. When this occurs, a new atom and element are formed. This process is called radioactive decay. It continues until the forces in the unstable nucleus are balanced
Describe what happens during a nuclear transformation
Nuclear Fusion reactions power the Sun and other stars. In a fusion reaction, two light nuclei merge to form a single heavier nucleus. The process releases energy because the total mass of the resulting single nucleus is less than the mass of the two original nuclei. The leftover mass becomes energy
Perform half-life calculations, including being able to determine how old a sample is given its half-life
Determine the original amount of the substance.
Determine the amount of time for which the substance was measured.
Determine the remaining amount of the substance after the time.
Substitute these values into the half-life equation and solve for half-life
Describe the difference between nuclear fusion and nuclear fission
Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei combine together releasing vast amounts of energy
