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Apologia Chem M 7
Describing Chemical Reactions
| Question | Answer |
|---|---|
| decomposition reaction | a reaction that changes a compound into its constituent elements |
| Whenever a molecule has a homonuclear diatomic in it, the decomposition reaction will produce | homonuclear diatomic molecules. |
| 1st step in predicting & balancing a decomposition reaction: | split the chemical formula into its individual elements |
| any reaction that has a SINGLE compound as the reactant & several elements or compounds as the products | a decomposition reaction |
| formation reaction | a reaction that starts with 2 or more elements and produces 1 compound |
| combustion | a chemical reaction where a substance reacts w/ oxygen gas |
| complete combustion reaction | a reaction in which O2 is added to a compound containing carbon & hydrogen to produce CO2 & H2O |
| incomplete combustion | when a substance containing carbon & hydrogen burns in an environment w/ limited oxygen, producing either carbon monoxide or plain carbon |
| What determines whether combustion is incomplete or complete? | the amount of oxygen available in an area |
| If a reasonable amount of oxygen is available during a combustion reaction, | carbon monoxide water will be formed. |
| If there is a serious shortage of oxygen, during a combustion reaction, | carbon (soot) and water will be produced. |
| When an automobile burns gasoline in a limited supply of oxygen (such as in a garage), it causes | incomplete combustion. |
| Catalytic converters | help reduce the amount of carbon monoxide in automobile exhaust by converting the carbon monoxide to carbon dioxide. |
| Required on all cars since 1975, catalytic converters are only about | 90% efficient, so cars still produce carbon monoxide. |
| The more soot that you see in your fireplace, | the more concerned you should be about the airflow around it. |
| atomic number | the # of PROTONS in an atom, the # ABOVE the symbol on the periodic table |
| atomic mass | tells us how HEAVY an atom is, the # BELOW the symbol on the periodic table |
| amu | atomic mass units, invented to deal w/ the mass of atoms |
| 1.00 amu | 1.66 X 10^-24 g (not an exact figure, must consider its sig figures) |
| 1 amu is approximately | 1 trillion trillionths the mass of 1 housefly |
| mole | used to count atoms or molecules in a sample of matter |
| Avogadro's number | 6.02 x 10^23 atoms or molecules |
| We measure the mass of ONE atom in | AMUs. |
| We measure the mass of one MOLE of an atom in | GRAMs. |
| We measure the mass of ONE MOLECULE in | AMUs. |
| We measure the mass of one MOLE of a MOLECULE in | GRAMS. |
| The mass of an atom gives us | a conversion relationship that relates grams to moles. |
| When you convert from grams to moles, you are taking a measurement that is very easy to obtain (mass) and | converting it into something that tells you how many molecules or atoms are present in a sample of matter (moles). |
| In chemical equations, the COEFFICIENTS that appear to the left of each substance give | the RATIO of moles of the substances used in the chemical equation. |
| A chemical equation does NOT give us the ratio of | grams; it ONLY gives us the ratio of moles. |