*Question*
Q: What is the greek word meaning "to help make things easier"? Read this paragraph and choose the correct option from the provided answers: 9.5 Simple Machines Simple machines are devices that can be used to multiply or augment a force that we apply often at the expense of a distance through which we apply the force. The word for "machine" comes from the Greek word meaning "to help make things easier. " Levers, gears, pulleys, wedges, and screws are some examples of machines. Energy is still conserved for these devices because a machine cannot do more work than the energy put into it. However, machines can reduce the input force that is needed to perform the job. The ratio of output to input force magnitudes for any simple machine is called its mechanical advantage (MA). Choices: - toy - battery - mode - machine A:
**Answer**
machine

*Question*
Q: This sharing of electrons produces what is known as a covalent bond. covalent bonds are ~20 to 50 times stronger than what? Read this paragraph and choose the correct option from the provided answers: any other electron, they become a part of the molecule's electron system.204 This sharing of electrons produces what is known as a covalent bond. Covalent bonds are ~20 to 50 times stronger than van der Waals interactions. What exactly does that mean? Basically, it takes 20 to 50 times more energy to break a covalent bond compared to a van der Waals interaction. While the bonded form of atoms in a molecule is always more stable than the unbounded form, it may not be stable enough to withstand the energy delivered through collisions with neighboring molecules. Different bonds between different atoms in different molecular contexts differ in terms of bond stability; the bond energy refers the energy needed to break a particular bond. A molecule is stable if the bond energies associated with bonded atoms within the molecule are high enough to survive the energy delivered to the molecule through either collisions with neighboring molecules or the absorption of energy (light). When atoms form a covalent bond, their individual van der Waals surfaces merge to produce a new molecular van der Waals surface. There are a number of ways to draw molecules, but the spacefilling or van der Waals surface view is the most realistic (at least for our purposes). While realistic it can also be confusing, since it obscures the underlying molecular structure, that is, how the atoms in the molecule are linked together. This can be seen in this set of representations of the simple molecule 2methylpropane ().205 As molecules become larger, as is the case with many biologically important molecules, it can become impossible to appreciate their underlying organization based on a van der Waals surface representation. Because they form a new stable entity, it is not surprising (perhaps) that the properties of a molecule are quite distinct from, although certainly influenced by, the properties of the atoms from which they are composed. To a first order approximation, a molecule's properties are based on its shape, which is dictated by how... Choices: - Mendelian systems - Newton's third law - gravitational pull - van der waals interactions A:
**Answer**
van der waals interactions

*Question*
Q: Salt hydrolysis is a reaction in which one of the ions from a salt reacts with what? Read this paragraph and choose the correct option from the provided answers: The fluoride ion is acting as a weak Brnsted-Lowry base. The hydroxide ion that is produced as a result of the above reaction makes the solution slightly basic. Salt hydrolysis is a reaction in which one of the ions from a salt reacts with water, forming either an acidic or basic solution. Choices: - proteins - fat - air - water A:
**Answer**
water

*Question*
Q: What do ocean mollusks use to absorb oxygen from the water? Read this paragraph and choose the correct option from the provided answers: Most ocean mollusks have a gill or gills to absorb oxygen from the water. Choices: - shells - scales - pores - gills A:
**Answer**
gills