Answer the following question given this paragraph: To prepare coal for use, the coal is first crushed into powder and burned in a furnace. Like other fuels, coal releases most of its energy as heat when it burns. The heat from the burning coal is used to boil water. This makes steam. The steam spins turbines, which creates electricity. Q: When does coal release most of its energy? Choices: - when forming - when compressed - when falling - when burning A:
when burning
(Question)
Answer the following question given this paragraph: The solubility of the majority of solid substances increases as the temperature increases. However, the effect is difficult to predict and varies widely from one solute to another. The temperature dependence of solubility can be visualized with the help of a solubility curve , a graph of the solubility vs. temperature (see Figure below ). Q: As temperature increases, the solubility of the majority of solid substances does what? Choices: - stays the same - reduces - mutates - increases A:
(Answer)
increases
Ques: Answer the following question given this paragraph: dissociated ions. It is a dynamic equilibrium because acid and base molecules are constantly dissociating into ions and reassociating into neutral molecules. The pH scale is a scale used to express the concentration of hydrogen ions in solution. A neutral solution, neither acidic nor basic, has a pH of 7. Acidic solutions have a pH lower than 7, while basic solutions have a pH higher than 7. Buffers are solutions that resist dramatic changes in pH when an acid or a base is added to them. They contain a weak acid and a salt of that weak acid, or a weak base and a salt of that weak base. When a buffer is present, any strong acid reacts with the anion of the salt, forming a weak acid and minimizing the presence of hydrogen ions in solution. Any strong base reacts with the weak acid, minimizing the amount of additional hydroxide ions in solution. However, buffers only have limited capacity; there is a limit to the amount of strong acid or strong base any given amount of buffer will react with. Q: The ph scale is a scale used to express the concentration of hydrogen ions in solution. a neutral solution, neither acidic nor basic, has a ph of what? Choices: - 6 - 0 - 8 - 7 A:
Ans: 7
(Q).
Answer the following question given this paragraph: Many extremely interesting objects can't be seen with the unaided eye. Astronomers use telescopes to see objects at wavelengths all across the electromagnetic spectrum. Some very hot stars emit light primarily at ultraviolet wavelengths. There are extremely hot objects that emit X-rays and even gamma rays. Some very cool stars shine mostly in the infrared light wavelengths. Radio waves come from the faintest, most distant objects. Q: What devices do astronomers use to see objects at wavelengths all across the electromagnetic spectrum? Choices: - microscopes - spectrographs - levels - telescopes A:
(A).
telescopes
Ques:Answer the following question given this paragraph: Chapter 9 1 Figure 9.10 Ligase, as this enzyme joins together Okazaki fragments. 2 A 4 B 6 A 8 C 10 D 12 The DNA is wound around proteins called histones. The histones then stack together in a compact form that creates a fiber that is 30-nm thick. The fiber is further coiled for greater compactness. During metaphase of mitosis, the chromosome is at its most compact to facilitate chromosome movement. During interphase, there are denser areas of chromatin, called heterochromatin, that contain DNA that is not expressed, and less dense euchromatin that contains DNA that is expressed. 14 Telomerase has an inbuilt RNA template. Q: The dna is wound around proteins called what? Choices: - leptons - nucleotides - pepsins - histones A:

Ans:histones
Ques: Answer the following question given this paragraph: f 2 = v w / 2 = v w / 2L = 2 f 1 . Similarly, f 3 = 3 f 1 , and so on. All of these frequencies can be changed by adjusting the tension in the string. The greater the tension, the greater v w is and the higher the frequencies. This observation is familiar to anyone who has ever observed a string instrument being tuned. We will see in later chapters that standing waves are crucial to many resonance phenomena, such as in sounding boxes on string instruments. Q: Stringed instruments can help show the relationship between tension and what in strings? Choices: - volumes - temperatures - lengths - frequencies A:
Ans:
frequencies