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Solubility of Starches

1. Some starch/carbohydrates, although soluble in warm water, become gel like once experincing a cold atmosphere. The commercial dessert, Jell-O, is composed of just this type of starch. Making the dessert Jell-O requires bringing to a boli a certain amount of water before adding in the powdered Jell-O crystals. Then, as soon as

Chemistry problems

1. 0.412 mol of a solid was dissolved in 200 mL of water at 21.2 oC. After the solid had fully dissolved, the final temperature of the solution was 17.9 oC. What is the molar heat of solution of the substance? _______________kJ/mol 2. Use Appendix B and the fact that the heats of formation of OF2 and OCl2 are 24.7 and 80.37

Bonding Structures and VSEPR Theory

Help with various molecular geom/chem bonding problems. Any explanations would be greatly appreciated. (See attached file for full problem description with chart) 1. Fill in the table below for each of the following compounds. The column headings refer to the central atom, which is shown in bold type. (VSEPR Model)

5 Questions on Ionic/Covalent Bonding

(See attached file for full problem description with diagrams) 1. Which bonds below are polar and which are nonpolar? If a bond is polar, indicate which end is positive and which end is negative. (Pol Cov Bonds -Electronegativity ) C-S F-C N-O Si-Br Cl-C 2. Briefly explain why each Lewis formula attached

Heat Required for Phase Conversion

The fluorocarbon C2Cl3F3 has a normal boiling point of 47.6 degrees C. The specific heats of C2Cl3F3(l) and C2Cl3F3(g) are 0.91J/g-K and 0.67J/g-L, respectively. The heat of vaporization for the compound is 27.49kj/mol. I need to find the heat required to convert 25.0g of C2Cl3F3 from a liquid at 5.00 degrees C to a gas at 82

Ionic substances and exothermic lattice

State which compound in each of the following pairs of ionic substances has the most exothermic lattice and why: NaCl, CaS Li2O, Na2O LiF, NaCl MgO, CaS Plus two requirements that should be satisfied for a molecule to be polar

Benzene Questions

1. Benzene is an organic solvent with the formula, C6H6. It boils at 80.1oC and melts at 5.5oC. Benzene's density is 0.88 gm/ml, its heat of vaporization is 20.0 KJoules per mole, its heat of fusion is 10.0 KJoules per mole, its heat capacity is 0.50 KJoules per mole-degree C for liquid benzene, 0.25 KJoules per mole-degree C fo

Ozonolysis of Myrcene

Myrcene, C10H16, a terpene, absorbs three moles of hydrogen to form C10H22. Upon ozonolysis myrcene yields the two compounds shown in the first attached .jpg (I5Q2a). 1. What structures for myrcene are consistent with the facts? 2. Based on the isoprene rule (naturally occurring terpenes are made up of isoprene segments)

PH problem - Buffer

1. A typical buffer used by biochemists is called Tris, which can be depicted as R3N (i.e. a tertiary amine). A buffer that is prepared by mixing 500 ml of 0.05 M R3N with 500 ml of 0.05 M R3NHCL at 25 degrees Celsius has a pH of 8.4. If this same buffer is placed in a cold room at 4 degrees Celsius, the pH decreases to 9.2.

Molecules, atoms, composition, descriptions, bonds

Select a molecule. List the atoms that that molecule is composed of and describe the type of bond that holds those atoms together. Be sure to explain how this bond works. The following template must be used to answer the question. Molecule Name: Atoms Found: Chemical Formula: Bonds Found: How Bonds Wor

Rate Constant and Periodic Trends

I need some help answering these two questions: 1. For the following balanced reaction, determine the rate expression and the rate constant, k, for it using the data given below. 2A + B +C yields D + 2E + F Experiment [A] mol/L [B] mol/L [C] mol/L Rate (M sec-1)

General Chemistry

A saturated solution _______________. a. cannot be attained b. contains dissolved solute in equilibrium with undissolved solid c. contains as much solvent as it can hold d. will rapidly precipitate if a seed crystal is added e. contains no double bonds Which one of the following is most soluble in water?

Completing Energy Calculations

Determine the total amount of energy lost when 35 g of water are cooled from 135 degrees C to 25 degrees C. Lable each of the six steps and show me the equations and calculations.

Solving General Chemistry Questions

Hi, I need assistance with the following questions: The electron configuration of the S2- ion is _______. a. [Kr]3s23p-6 b. [Ne]3s23p2 c. [Ar]3s23p2 d. [Ar]3s23p6 e. [Ne]3s23p6 Of the compounds below, _____ has the smallest ionic separation. a. SrBr2 b. KF c. RbCl d. Rbf e. K2S Given the electronegativities b

Molecular Geometry and Bonding

The basis of the VSEPR model of molecular bonding is ____________. a. regions of electron density on an atom will organize themselves so as to maximize s-character b. atomic orbitals of the bonding atoms must overlap for a bond to form c. hybrid orbitals will form as necessary to,

Orbitals, subshell, pressure, and chemical formula

Please help with the following questions. Question 6 The formula CH3CH2CH2=CH2 represents an alkene an alkyne an alcohol benzene Question 7 The number of orbitals in a d subshell is: 1 2 3 5 7 Question 8 _____ is credited with the modern structure of the

Molecular Geometry

For each molecule, draw the Lewis structure first, then apply the VSEPR model according to the following rules: 1. Count the number of electron pairs around the central atom (both bonding pairs and unshared pairs). Treat double and triple bonds as if they were single bonds. 2. Refer to the table given below to predict the geom

A complete molecular diagram fo C2 2- and determine the bond order.

The problem to solve is to formulate in which way two carbon atoms are described by using atomic orbitals. First one has to find out the electronic structure of a carbon atom by locating this element in the periodic table. Second step is then to fill the orbitals with the given number of electrons using Hund's rule. The third

General Chemistry

4.81 Which of these aqueous solutions would you expect to be the best conductor of electricity at 25° C? Explain your answer? (a) 0.20M NaCl (b) 0.60M CH3COOH (c) 0.25M HCl (d) 0.20M Mg (NO3)2

Multiple Choice Questions

6 ) Iron has a density of 7.86 g/cm3. The volume occupied by 55.85 g of iron is: 7 ) Which pair of elements would be most likely to form an ionic compound? P and Br Cu and K C and O O and Zn Al and Rb 8 ) Which is the formula for the binary compound of potassium and nitrogen? KN K2N NK2

Epitaxy, Berry's Rotation, Polarization, IR spectroscopy, Rochow

This is a past exam for practice. Please complete question 5 only. 20 5. Write brief notes on any four of the following: a. Metal-organic vapor phase epitaxy b. Berry's rotation. c. Effect of polarization on melting points d. IR spectroscopy as a tool for structure determination of inorganic compounds e. Rochow pr

Multiple choice

Out of 250 questions, I am unsure of the following: 1.For a given substance that exhibits liquid-crystalline properties, the transition from solid to liquid-crystal state occurs: a.over a range of temperatures that includes the melting point of the soild. b. at a well defined temperture above the melting point of the solid.

Bonding in coordination chemistry

Why do square planar geometries occur in d7, d8, and d9 ions with strong field- pi acceptor ligands, except in cases in which ligand geometry requires it?