Chemistry Final Semester 1 – Flashcards
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| what is chemistry? |
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| the study of the comoposition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes. |
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| what is matter? |
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| anything that has mass and takes up space |
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| what is the smallest unit of element that maintains the chemical identity of that element? |
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| atom |
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| what is a compound? give an example |
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| a substance that can be broken down into simple stable substances. each compound is made from the atoms of two or more elements that are chemically bonded; water |
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| what is a physical property? |
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| a characteristic that can be observed or measured without changing the identity of the substance |
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| what is a physical change? |
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| a change in a substance that does not involve a change in the identity of the substance. |
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| know the state of volume and shape for solids, liquids, and gases. |
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| solid: definite volume and definite shape. liquid: definite volume, indefinite shape. gas: indefinite volume, indefinite shape. |
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| what is a chemical property? |
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| related to a substance's ability to undergo changes that transform it into different substances |
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| know what reactants and products are |
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| reactants: the substances that react in a chemical change products: the substances that are formed by the chemical change |
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| what are homogeneous mixtures also known as? |
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| solutions |
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| give an example of a heterogenous mixture |
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| clay and water |
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| what are SI units defined in terms of? what is used for the standards? |
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| they have 7 base units, and most other units are derived from these 7. the standards are objects or natural phenomena that are of constant value, easy to preserve and reproduce, and practical in size. |
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| what is the difference between mass and weight? |
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| mass doesn't depend on gravity like weight does. |
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| what is volume? |
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| the amount of space occupied by an object |
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| what is density? what's its formula? |
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| the ratio of mass to volume, or mass divided by volume. denisity=mass/volume |
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| what are significant figures? |
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| consist of all the digits known with certainty plus one final digit, which is somewhat uncertain or is estimated |
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| what's the difference between accuracy and precision? |
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| accuracy means getting a result that's close to the real answer, precision is getting a similar result every time you try |
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| law of conservation of mass |
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| states that mass is neither created nor destroyed during ordinary chemical reactions or physical changes |
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| law of multiple proportions |
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| if 2 or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of the small whole numbers |
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| law of definite proportions |
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| the fact that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound |
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| mass number |
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| the total number of protons and neutrons that make up the nucleus of an isotope |
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| what speed to visible light, x rays, infrared and all electromagnetic radiation travel? |
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| 3 x 10^8 |
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| as wavelength increases, what happens to frequency? |
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| decreases |
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| definition of wavelength? does red light or blue light have a longer wavelength? |
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| the difference between corresponding points on adjacent waves. usually in meters, centimeters, or nanometers; red |
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| definition of frequency? what has higher frequency, x-rays or yellow light? |
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| the number of waves that pass a given point in a specific type, usually one second; x-rays |
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| as frequency increases, what happens to energy? |
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| increases |
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| what is a line emission spectrum? |
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| 4 specific colors of the visible spectrum when a narrow beam of the emitted light was shined through a prism. |
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| for an electron in an atom to change from the ground state to an excited state, energy must be |
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| absorbed |
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| when an electron changed from the excited state to the ground state, energy must be |
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| released |
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| which indicates a bigger jump, blue spectral line or red? |
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| red |
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| what are the shapes of the S and P orbitals? |
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| S: sphere. P: dumbell |
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| hund's rule |
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| 1 electron will enter each of the 3 p orbitalsin a main energy level before a second electron enters them. |
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| aufbau |
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| lowest-energy orbital |
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| pauli exclusion |
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| specify energy, shape, and orientation |
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| what is a valence electron? |
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| the electrons available to be lost, gained, or shared in the formation of chemical compounds. |
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| what is the difference between a cation and anion |
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| positive ions are cations and negative ions are anions |
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| what is electronegativity? |
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| a measure of the ability of an atom in a chemical compound to attract electrons from another atom in the compound. |
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| what is electron affinity? |
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| the energy change that occurs when an electron is acquired by a neutral atom |
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| what is a chemical bond? |
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| a mutual electrical attractive between the nuclei and valence electrons of different atoms that binds the atoms together |
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| what is the difference between ionic and covalent bonding? |
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| ionic results from the electrical attraction between cations and anions. covalent results from the sharing of electron pairs between two atoms. |
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| what are the similarities and differences between non-polar covalent and polar covalent bond? |
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| non polar: shared equally by the bonded atoms polar covalent: unequal attraction for the shared electrons |
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| what is the relationship between a molecular formula and chemical formula? |
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| the chemical formula of a molecular compound is the molecular formula |
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| what is a molecule? |
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| a neutral group of atoms that are held together by covalent bonds |
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| what is bond length? |
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| the distance between two bonded atoms |
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| what is bond energy? |
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| the energy required to break a chemical bond and form neutral isolated atoms. |
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| what are the opposing factors in a covalent bond? |
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| sharing electrons |
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| what is the octet rule? |
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| chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of electrons in its highest occupied energy level. |
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| what is a resonance structure? |
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| bonding in molecules or ions that cannot be correctly represented by a single Lewis structure; oxygen bonds |
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| what is an ionic compound? |
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| composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal. |
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| what is a formula unit? |
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| the simplest collection of atoms from which an ionic compound's formula can be established |
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| what is lattice energy? |
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| the energy released released when one mole of an ionic crystalline compound is formed from gaseous ions. |
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| what is a polyatomic ion? |
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| a charged group of covalently bonded atoms |
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| what is metallic bonding? |
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| the chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons |
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| define malleability and ductility |
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| malleability: the ability of a substance to be hammered or beaten into thin sheets ductility: the ability of a substance to be drawn, pulled, or extruded through a small opening to produce a wire |
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| why aren't ionic compounds malleable and ductile? |
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| because shifting the layers of an ionic crystal causes the bonds to break and the crystal to shatter |
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| what does VSEPR stand for? |
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| valence-shell, electron-pair repulsion |
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| what does the VSEPR theory state? |
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| the repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far apart as possible |
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| how do lone pairs of electrons influence molecular shape? |
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| only molecules with no unshared valence electrons pairs on the central atom |
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| what is hybridization? |
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| the mixing of two or more atomic orbitals of similar energies on the same atom to produce new hybrid atomic orbitals of equal energies |
