Answer the following question given this paragraph: Reactions and Compounds of Nitrogen Like carbon, nitrogen has four valence orbitals (one 2s and three 2p), so it can participate in at most four electron-pair bonds by using sp3 hybrid orbitals. Unlike carbon, however, nitrogen does not form long chains because of repulsive interactions between lone pairs of electrons on adjacent atoms. These interactions become important at the shorter internuclear distances encountered with the smaller, second-period elements of groups 15, 16, and 17. (For more information on internuclear distance, see Chapter 7 "The Periodic Table and Periodic Trends", Section 7.2 "Sizes of Atoms and Ions" and Chapter 8 "Ionic versus Covalent Bonding", Section 8.2 "Ionic Bonding". ) Stable compounds with NN bonds are limited to chains of no more than three N atoms, such as the azide ion (N 3). Nitrogen is the only pnicogen that normally forms multiple bonds with itself and other second-period elements, using overlap of adjacent np orbitals. Thus the stable form of elemental nitrogen is N 2, whose NN bond is so strong (DNN = 942 kJ/mol) compared with the NN and N=N bonds (DNN = 167 kJ/mol; DN=N = 418 kJ/mol) that all compounds containing NN and N=N bonds are thermodynamically unstable with respect to the formation of N2. In fact, the formation of the NN bond is so thermodynamically favored that virtually all compounds containing NN bonds are potentially explosive. Again in contrast to carbon, nitrogen undergoes only two important chemical reactions at room temperature: it reacts with metallic lithium to form lithium nitride, and it is reduced to ammonia by certain microorganisms. (For more information lithium, seeChapter 21 "Periodic Trends and the ". ) At higher temperatures, however, N2 reacts with more electropositive elements, such as those in group 13, to give binary nitrides, which range from covalent to ionic in character. Like the corresponding compounds of carbon, binary compounds of nitrogen with oxygen, hydrogen, or other nonmetals are usually covalent molecular... Q: What is the most electron-pair bonds a nitrogen atom can participate in? Choices: - seven - five - three - four A:
four
(Question)
Answer the following question given this paragraph: Butter is a fat that is a solid at room temperature. What type of fatty acid does butter contain? How do you know?. Q: What else besides temperature has an effect on the phase of a substance? Choices: - weight - resistance - energy - pressure A:
(Answer)
pressure
Ques: Answer the following question given this paragraph: The device in the circuit in Figure above is an ammeter. It measures the current that flows through the wire. The faster the magnet or coil moves, the greater the amount of current that is produced. If more turns were added to the coil, this would increase the strength of the magnetic field as well. If the magnet were moved back and forth repeatedly, the current would keep changing direction. In other words, alternating current would be produced. This is illustrated in Figure below . Q: What device measures current that flows through wire? Choices: - protractor - resistor attachment - Geiger counter - ammeter A:
Ans: ammeter
(Q).
Answer the following question given this paragraph: 12.5 The Onset of Turbulence Sometimes we can predict if flow will be laminar or turbulent. We know that flow in a very smooth tube or around a smooth, streamlined object will be laminar at low velocity. We also know that at high velocity, even flow in a smooth tube or around a smooth object will experience turbulence. In between, it is more difficult to predict. In fact, at intermediate velocities, flow may oscillate back and forth indefinitely between laminar and turbulent. An occlusion, or narrowing, of an artery, such as shown in Figure 12.17, is likely to cause turbulence because of the irregularity of the blockage, as well as the complexity of blood as a fluid. Turbulence in the circulatory system is noisy and can sometimes be detected with a stethoscope, such as when measuring diastolic pressure in the upper arm's partially collapsed brachial artery. These turbulent sounds, at the onset of blood flow when the cuff pressure becomes sufficiently small, are called Korotkoff sounds. Aneurysms, or ballooning of arteries, create significant turbulence and can sometimes be detected with a stethoscope. Heart murmurs, consistent with their name, are sounds produced by turbulent flow around damaged and insufficiently closed heart valves. Ultrasound can also be used to detect turbulence as a medical indicator in a process analogous to Doppler-shift radar used to detect storms. Q: Turbulent sounds, at the onset of blood flow when the cuff pressure becomes sufficiently small are called? Choices: - pinworm sounds - whooping sounds - choanocyte sounds - korotkoff sounds A:
(A).
korotkoff sounds
Ques:Answer the following question given this paragraph: A mutation is a change in the base sequence of DNA or RNA. Environmental causes of mutations are called mutagens. The effects of a mutation depend on the type of mutation and whether it occurs in a gamete or body cell. Q: What is the term for environmental causes of mutations? Choices: - pollutants - catalysts - carcinogens - mutagens A:

Ans:mutagens
Question: Answer the following question given this paragraph: Beginning with Mendel's pea plants, genetics has become one of the most important fields of biology. Genetics discusses genetics, from Mendel's pea plants to current ethical issues associated with this field. The completion of The Human Genome Project is one of the landmark scientific events of the last 50 years. Human genetics affects many, if not every, field of medicine. Technologies associated with genetics are involved in developing products to make our lives better, but have raised a number of ethical, legal and social issues. Q: What is the name of the project concerning genetics that is one of the landmark scientific events of the last 50 years? Choices: - human organism project - manhattan project - blue beam project - human genome project A:
Answer:
human genome project