Chemistry Structure And Bonding Exam Questions
Isabella Kells
The Chemistry exam covers material that is usually taught in a one-year college course in general chemistry. Understanding of the structure and states of matter, reaction types, equations and stoichiometry, equilibrium, kinetics, thermodynamics, and descriptive and experimental chemistry is required, as is the ability to interpret and apply this material to new and unfamiliar problems. During this exam, an online scientific calculator function and a periodic table are available as part of the testing software.
To use the calculator during the exam, students need to select the Calculator icon. Information about how to use the calculator is available in the Help icon under the Calculator tab. Students are expected to know how and when to make appropriate use of the calculator.
Visit ETS to learn more and to practice using the scientific calculator.. Students will find the online scientific calculator helpful in performing calculations (e.g., arithmetic, exponents, roots, and logarithms).
Some questions are based on laboratory experiments widely performed in general chemistry and ask about the equipment used, observations made, calculations performed, and interpretation of the results. The questions are designed to provide a measure of understanding of the basic tools of chemistry and their applications to simple chemical systems.
Note: Each institution reserves the right to set its own credit-granting policy, which may differ from the American Council on Education (ACE). Contact your college to find out the score required for credit and the number of credit hours granted.
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In the exploding question technique, learners annotate the question, or associated diagrams, with important facts relevant to the topic. This guides them to better answers to extended-response exam questions.
Use the PowerPoint slides to introduce example one, a real past-paper question. Slide four shows how to annotate the question; command words/key instructions are boxed and key words within the question are underlined.
Then, ask your learners to write their answers independently. By ticking or highlighting when a point is included they can ensure they have covered all necessary information, hopefully maximising their marks. Share the marking guidance (slide seven) with learners so they can check how successful they have been.
Example two provides another, similar question to give learners the opportunity to practise the technique. Ask them to work on their own first, then discuss their exploded question in pairs or small groups before writing an answer.
Alternatively, you can support learners with writing answers to extended-response questions using structure strips, find more information and template. This may be useful for learners who need more support with the writing part of the task.
Class 11 chemistry important questions with answers are provided here for Chapter 4 Chemical Bonding and Molecular Structure. These important questions are based on the CBSE board curriculum and correspond to the most recent Class 11 chemistry syllabus. By practising these Class 11 important questions, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 11 Annual examinations as well as other entrance exams such as NEET and JEE.
(c) Due to intramolecular hydrogen bonding, compound (I) cannot form hydrogen bonds with water and is thus less soluble in it, whereas compound (II) can form hydrogen bonds with water more easily and is thus more soluble in water.
P is surrounded by 5 bond pairs and no lone pairs in PCl5, whereas iodine atom is surrounded by 5 bond pairs and one lone pair in IF5, so the shape of PCl5 is trigonal bipyramidal and IF5 is square pyramidal
The bond angle of dimethyl ether will be greater. More repulsion will exist between bond pairs of CH3 groups attached in ether than between bond pairs of hydrogen atoms attached to oxygen in the water.
The carbon of CH3 in ether is attached to three hydrogen atoms via bonds, and the electron pair of these bonds contribute to the electronic charge density on the carbon atom. As a result, the repulsion between two CH3 groups will be greater than that between two hydrogen atoms.
(i) A covalent bond is formed by the overlapping of half-filled atomic orbitals with definite directions, i.e., shared electron pair/pairs are localised between two atoms. As a result, a covalent bond is also known as a directional bond. Since each ion in an ionic compound has an influence in all directions, it is surrounded by a number of oppositely charged ions with no definite direction and, therefore, is non-directional.
(ii) The central oxygen atom in water is sp3 hybridised, whereas the central carbon atom in CO2 is sp-hybridised. The net dipole moment of CO2 is zero, whereas H2O has a significant value. This demonstrates that CO2 has a linear structure, whereas water has a bent structure.
Ionic bonds are chemical bonds formed between two atoms as a result of the transfer of one or more electrons from one atom to the other. Such a bond is only possible between atoms of different characteristics, with one atom having a tendency to lose electrons and the other atom having a tendency to accept electrons.
(b) It is possible to predict the nature of a chemical bond formed by knowing the electronegativities of the atoms involved in a molecule. The bond will be highly polar if the difference in electronegativities between two atoms is large. An ionic bond is formed when an electron is completely transferred from one atom to another.
(d) Differentiate between cis- and trans-isomers. Dipole moment measurements aid in the differentiation of cis- and trans-isomers because the ds-isomer has a higher dipole moment than the trans isomer.
(e) Distinguish between ortho, meta and para isomers. Dipole moment measurements aid in the differentiation of o-, m-, and p-isomers because the dipole moment of the p-isomer is zero and that of the o-isomers is greater than that of the m-isomer.
3. Briefly describe the valence bond theory of covalent bond formation by taking an example of hydrogen. How can you interpret energy changes taking place in the formation of dihydrogen?
Heitler and London proposed the valence bond theory in 1927. Later, in 1931, L. Pauling and J.C. Slater improved and developed it. The valence bond theory is based on knowledge of atomic orbitals and electronic configurations of elements, atomic orbital overlap criteria, and molecule stability.
(iv) Bond stability is explained by the fact that bond formation is accompanied by the release of energy. At a certain distance between the atoms, the molecule has the least amount of energy. This is known as internuclear distance. The stronger the bond formed, the greater the decrease in energy.
Assume that the two atoms are at a great distance from each other and that there is no interaction between them. They are now thought to be approaching each other, and new attractive and repulsive forces begin to operate.
It has been discovered that the magnitude of the new attractive force is greater than the magnitude of the new repulsive forces. As a result, two atoms approach each other, reducing potential energy. Eventually, the net force of attraction equals the net force of repulsion, and the system acquires the least amount of energy. Two hydrogen atoms are said to be bonded together at this point to form a stable molecule with a bond length of 74pm.
4. Describe hybridization in the case of PCl5 and SF6. The axial bonds are longer as compared to equatorial bonds in PCl5 whereas in SF6, both axial bonds and equatorial bonds have the same bond length. Explain.
Molecular orbitals are formed by the overlap of atomic orbitals. Two atomic orbitals combine to form two molecular orbitals called bonding molecular orbital (BMO) and antibonding molecular orbital (ABMO). Energy of antibonding orbital is raised above the parent atomic orbitals that have combined and the energy of the bonding orbital is lowered than the parent atomic orbitals. Energies of various molecular orbitals for elements hydrogen to nitrogen increase in the order :
Bond Length is approximately equal to the sum of the covalent radii of the two bonded atoms. In other words, Bond length is the measurable distance between atoms covalently bonded together. Click here to learn about the Bond Characteristics
The cause of the d-block contraction is the poor shielding of the nuclear charge by the electrons in the d orbitals. The d-block contraction can be compared to the lanthanide contraction, which is caused by inadequate shielding of nuclear charge by electrons occupying f orbitals. Click here to learn more about Lanthanide contraction.
Chemical bonding refers to the formation of a chemical bond between two or more atoms, molecules or ions to give rise to a chemical compound. These chemical bonds are what keep the atoms together in the resulting compound.
The attractive force which holds various constituents (atoms, ions, etc.) together and stabilises them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between their constituents; the stronger the bonding between the constituents, the more stable the resulting compound will be.
The opposite also holds true; if the chemical bonding between the constituents is weak, the resulting compound would lack stability and would easily undergo another reaction to give a more stable chemical compound (containing stronger bonds). To find stability, the atoms try to lose their energy.
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