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 |