Matter Unit Study Guide – Flashcards
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matter
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Anything that has mass and takes up space
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Properties of Matter
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determined by the structure of its atoms and how they are joined
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atoms
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building blocks of matter
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mass
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amount of matter in an object
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kilograms
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measure mass
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atomic theory of matter
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every substance is made of atoms, there are only a certain number of the kinds of atoms in the universe, in all forms of matter there are only different arrangements of these same kinds of atoms
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size of atoms
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less than 1 million average atoms side by side is equal to the thickness of paper
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Nucleus
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small central core in the atom, made of protons and neutrons
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proton
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positive
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atomic number
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the number of protons in the nucleus, it identifies the atom and the element
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neutron
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neutral, adds to mass of an atom
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radioactivity
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caused by a loss of neutrons
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how to find the amount of neutrons
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mass number - protons = neutrons
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electron energy levels
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negative charge, insignificant mass
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atomic number =
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number of electrons in energy levels
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mass number
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number of protons and neutrons, round the atomic mass, use it to find neutrons
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Atomic mass
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average of all mass numbers
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isotopes
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atom of an element that has the same number of protons as another atom of the same element, but a different number of neutrons each isotope has its own mass number
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pure substance
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a substance with constant composition, can be classified as either an element or as a compound (table salt NaCl)
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element
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a substance that cannot be separated into two or more substances by normal chemical means (or physical means), elements are composed of only one type of atom, example - iron Fe
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normal chemicals means
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exclude nuclear reactions
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compound
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a substance that contains two or more elements in definite proportion by weight, the composition of a pure compound will be the same, regardless of the method of preparation, composed of more than one kind of atom sodium chloride NaCl
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molecule
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the smallest unit of a compound that still retains all of the properties of the compound
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physical properties and changes
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have to do with appearance, they can be observed by your senses and by measuring the length, width, height, mass and density of a substance
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examples of physical properties and changes
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melting, color change, crumpling
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chemical properties and changes
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how substances react with other substances a substance will change into something new and different
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examples of chemical properties and changes
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digestion, combustion, radioactivity
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mixtures
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two or more substances combined in varying proportions - each retaining its own specific properties
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separating components of mixtures
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by physical means without making and breaking of chemical bonds
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heterogeneous mixture
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mixture in which the properties and composition are not uniform throughout the sample (cereal, concrete, party mix)
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homogeneous mixture
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mixture in which the properties and composition are uniform throughout the sample
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solutions
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a solute dissolves in a solvent (water is the universal solvent)
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solubility
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the amount of solute a solvent can dissolve and dependent on temperature
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saturated solution
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a solvent has dissolved all the solute it can at a certain temperature
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rate of solution
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causing the solute to dissolve more quickly in the solvent
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three ways to increase the rate of dissolving
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stirring - moves particle crushing - exposes more of the solutes surface area to the solvent heating the solvent-the particles of the solvent are moving more quickly
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kinetic molecular theory
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matter is made of particles (molecules) that are in constant motion as thermal energy is added, kinetic energy of particles (temperature) increases As thermal energy is removed kinetic energy of particles (temperature) decreases Particles move faster and spread apart as their kinetic energy increases and move more slowly and get closer together as their kinetic energy decreases
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State of matter is determined by
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kinetic energy of particles
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latent heat
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amount of energy released or absorbed during a change of state
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heat of fusion
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heat of fusion is the amount of heat energy needed to change state of matter from a solid into a liquid or vice versa, temperatures remain constant
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melting / freezing point
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point at which a substance changes from a solid to liquid or vice versa
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heat of vaporization
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the amount of heat energy needed to change state of matter from a liquid into a gas, or vice versa, temperature remains constant (being absorbed)
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boiling point
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point at which a substance changes from a liquid to a gas
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density
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the mass of a substance divided by its volume
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density equation
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D = m/v
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buoyancy
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change in density of water
