Exam 2 – Chemistry Test Answers – Flashcards
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| What becomes a source of energy? |
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| Heat |
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| Heat is the source of what? |
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| Energy |
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| What do we use to supply the energy we need? |
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| Chemical reactions. |
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| What do chemical reactions supply? |
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| Energy |
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| What is 1 cal? |
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| The amount of heat needed to raise the temperature of 1 g of water by 1C |
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| What is the amount of heat needed to raise the temperature of 1 g of water by 1C? |
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| 1 cal |
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| Exothermic reactions...? |
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| Produce heat. |
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| Endothermic reactions...? |
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| Absorb heat energy from surroundings. |
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| What type of reaction absorbs heat energy from surroundings? |
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| Endothermic. |
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| What type of reaction produces heat? |
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| Exothermic. |
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| Carbohydrates provide...? |
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| 4 kcal/g (4 Cal/g) |
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| Proteins provide...? |
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| 4 kcal/g (4 Cal/g) |
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| Fats provide...? |
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| 9 kcal/g (9 Cal/g) |
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| What is the rate of a reaction? |
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| The amount of products formed from reactants in a given period of time. |
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| What is the collision theory? |
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| Views the rate of a reaction as the result of particles colliding with certain frequency and minimum energy. |
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| Views the rate of a reaction as the result of particles colliding with certain frequency and minimum energy. |
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| Collision theory |
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| What must reactants do for a reaction to occur? |
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| Must collide, collide with proper orientation, and collide with sufficient energy. |
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| In an exothermic reaction who has the lower energy? |
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| Products are lower energy than the reactants. |
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| in an endothermic reaction who has the lower energy? |
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| In an endothermic reaction the reactants are lower energy than products. |
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| What are factors that affect reaction rates? |
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| Concentration, temperature, or presence of a catalyst. |
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| What effect does concentration have on reaction rates. |
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| More reactants = more collisions. |
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| What effect does temperature have on reaction rates? |
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| Higher speeds = more collisions. |
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| What does the coefficient in a reaction equation stand for? |
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| The number of molecultes (mols) |
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| Define equilibrium. |
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| The rate of the reactants to products is the same as the rate of products to reactants. |
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| What is the equilibrium constant? |
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| K = (products)/(reactants) |
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| K = (products)/(reactants) |
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| Equilibrium constant |
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| Preferred bonding pattern for H. |
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| H- |
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| Preferred bonding patterns for C |
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| l -C- l >C= =C= -C(tri)C- |
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| Preferred bonding patterns for N |
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| .. -N - l .. - N - l :N(tri) |
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| Preferred bonding patterns for O |
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| .. -O - '' .. O = '' |
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| Preferred bonding patterns for S |
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| .. - S- '' |
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| What is the VSEPR Theory? |
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| Electron charge clouds will arrange themselves to be as far away from each other as possible. |
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| What is electronegativity? |
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| The ability of an atom to attract bonding electrons of a covalent bond to itself. |
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| 0 < 0.4 electronegativity |
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| Nonpolar |
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| Nonpolar bond in electronegativity |
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| 0 < 0.4 |
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| 0.4 > |
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| Polar |
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| Polar bond in electronegativity |
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| 0.4 > |
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| if the central atom has one or more pairs of nonbonding electrons, the molecule is...? |
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| Polar. |
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| If the central atom has no nonbonding pairs of electrons and all other atoms connected to the central atom are identical, the molecule is...? |
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| Nonpolar. |
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| If the central atom has no nonbonding pairs of electrons and at least one of the atoms connected to the central atom is different from the others, the molecule is...? |
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| Polar. |
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| Chromium ions |
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| Cr(2+ or 3+) |
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| Manganese ions |
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| Mn 2+ |
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| Iron ions |
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| Fe 2+ or 3+ |
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| Nickel ions |
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| Ni 2+ |
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| Copper ions |
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| Cu 1+ or 2+ |
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| Zinc ions |
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| Zn 2+ |
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| A combination reaction is? |
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| Elements or simple compounds that react to make a more complicated compound. |
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| Elements or simple compounds that react to make a more complicated compound. |
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| Combination reaction |
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| Reactant is split into simpler compounds. |
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| Decomposition. |
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| A reaction with oxygen |
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| Combustion. |
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| Decomposition |
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| Reactant is split into simpler compounds. |
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| Combustion |
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| A reaction with oxygen. |
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| Single Replacement reaction |
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| One atom replaces another atom in a second compound (cation with cation). |
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| One atom replaces another atom in a second compound (cation with cation). |
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| Single replacement reaction |
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| What are the diatomic elements? |
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| H2, N2, F2, O2, I2, Cl2, Br2 |
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| Double Replacement reaciton |
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| Positive ions switch places when two ionic compounds react. |
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| Positive ions switch places when two ionic compounds react. |
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| Double Replacement. |
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| What do saturated hydrocarbons contain? |
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| Only carbon-carbon single bonds. |
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| Simple organic compound names. |
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| Meth, eth, prop, but, pent, hex, hept, oct, non, dec. |
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| What are structural isomers? |
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| Compounds with same molecular formula, but different connectivity. |
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| Compounds with same molecular formula but different connectivity. |
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| Structural isomer. |
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| Stereoisomers are...? |
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| Compounds which differ from each other by their arrange of atoms in space. |
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| Compounds which differ from each other by their arrange of atoms in space. |
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| Stereoisomers. |
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| What are responsible for the spearmint and caraway seed flavor? |
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| A pair of stereoisomerrs called carvones that are taste buds can distinguish between them |
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| Difference between spearmint and caraway is... |
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| The stereoisomers are identical except for the arrangement of groups in space. |
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| Enantiomers are... |
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| Mirror images, but cannot be simply flipped because of 3-dimensionality. |
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| Mirror images, but cannot be simply flipped because of 3-dimensionality. |
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| Enantiomers. |
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| What is a chiral center? |
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| A tetrahedral carbon bonded to four different atoms or groups of atoms. Molecules with a chiral center form mirror images that are nonsuperimposable. |
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| What are intermolecular forces? |
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| The attractive forces between molecules. |
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| What are the attractive forces between molecules called? |
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| Intermolecular forces. |
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| What is weaker: intermolecular forces or covalent bonds? |
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| Intermolecular forces. |
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| What is the weakest of the forces? |
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| London (dispersion forces) |
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| When do london forces occur? |
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| Momentarily in all molecules when electrons become unevenly distributed over a molecule's surface. |
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| What is created in london forces? |
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| An induced dipole. |
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| Where are london forces significant in? |
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| Nonpolar molecules. |
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| When is a permanent dipole created? |
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| Only in polar molecules. |
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| What must be always done in when comparing intermolecular forces? |
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| Comparing molecules of similar molecular weight. |
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| When do dipole-dipole attractions occur? |
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| Between the dipoles of two polar molecules. |
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| What is hydrogen bonding? |
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| Interaction between two molecules, a donor and an acceptor. |
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| What is the hydrogen donor? |
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| A molecule with a hydrogen atom covalently bonded to an O, N or F |
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| What is the hydrogen acceptor? |
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| A molecule with a nonbonding pair of electrons on an O, N or F |
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| A molecule with a nonbonding pair of electrons on an O, N or F |
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| Hydrogen acceptor |
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| A molecule with a hydrogen atom covalently bonded to an O, N or F |
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| Hydrogen donor |
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| What is the strongest of the intermolecular forces? |
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| Hydrogen bonding. |
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| When is something soluble? |
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| Like dissolves like, soluble if the molecules can bond. |
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| What is the golden rule of solubility? |
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| Molecules that have similar polarity and participate in the same types of intermolecular forces will dissolve each other. |
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| Molecules that have similar polarity and participate in the same types of intermolecular forces will dissolve each other. |
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| What is the golden rule of solubility? |
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| Can there be cis-trans in single bonds? |
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| No. |
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| What can have cis-trans? |
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| Ring structures and double bonds. |
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| AB2 |
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| Linear |
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| Linear |
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| AB2 |
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| AB3 |
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| Trigonal planar |
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| Ab2N |
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| Bent |
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| Bent |
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| Ab2N |
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| Trigonal planar |
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| AB3 |
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| Ab4 |
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| Tetrahedral |
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| Tetrahedral |
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| Ab4 |
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| Ab3N |
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| Pyramidal |
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| Pyramidal |
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| Ab3N |
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| Ab2N2 |
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| Bent |
