Q: A constant and plentiful supply of oxygen is required in order to maintain a high rate of what? Read this paragraph and choose the correct option from the provided answers: Keeping the rate of metabolism high takes a constant and plentiful supply of oxygen. That's because cellular respiration, which produces energy, requires oxygen. The lungs and heart of mammals are adapted to meet their oxygen needs. Choices: - digestion - cell division - magnesium - metabolism A:
metabolism
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Q: Transferring what from sodium to chlorine decreases the radius of sodium by about 50%? Read this paragraph and choose the correct option from the provided answers: The sum of the calculated atomic radii of sodium and chlorine atoms is 253 pm. The sodium cation is significantly smaller than a neutral sodium atom (102 versus 154 pm), due to the loss of the single electron in the 3s orbital. Conversely, the chloride ion is much larger than a neutral chlorine atom (181 versus 99 pm), because the added electron results in greatly increased electronelectron repulsions within the filled n = 3 principal shell. Thus, transferring an electron from sodium to chlorine decreases the radius of sodium by about 50%, but causes the radius of chlorine to almost double. The net effect is that the distance between a sodium ion and a chloride ion in NaCl is greaterthan the sum of the atomic radii of the neutral atoms. Choices: - quark - proton - neutron - electron A:
electron
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Q: What is the the force of attraction that holds together ions? Read this paragraph and choose the correct option from the provided answers: An ionic bond is the force of attraction that holds together positive and negative ions. It forms when atoms of a metallic element give up electrons to atoms of a nonmetallic element. Choices: - covalent bond - soluble bond - magnetic bond - ionic bond A:
ionic bond
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Q: Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of br per what? Read this paragraph and choose the correct option from the provided answers: electrolysis2NaOH ( aq )+Cl2 ( g )+H 2 ( g ) Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of Br per liter. Salt lakes and underground brines are even richer sources; for example, the Dead Sea contains 4 g of Br per liter. Iodine is the least abundant of the nonradioactive halogens, and it is a relatively rare element. Because of its low electronegativity, iodine tends to occur in nature in an oxidized form. Hence most commercially important deposits of iodine, such as those in the Chilean desert, are iodate salts such as Ca(IO3)2. The production of iodine from such deposits therefore requires reduction rather than oxidation. The process is typically carried out in two steps: reduction of iodate to iodide with sodium hydrogen sulfite, followed by reaction of iodide with additional iodate: Equation 22.41. Choices: - pound - foot - gallon - liter A:
liter
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