chemistry practice questions

1. Multiple Choice: Choose the best answer and put the number in the blank provided. (45pts)

A. _______ Compounds that have only non-metal element and only covalent bonds are 1. Didactic 2. Nobel Compounds 3. Ionic 4. Molecular B._______ The Atomic Mass on the periodic table is: 1. The mass of the protons in an atom 2. The mass of a mole of atoms of a given element 3. The mass of an atom. 4. The Mass of a mole of protons C._______ What is the major attractive force in a compound like NaCl? 1. Dipole-dipole, 2. London dispersion, 3. Ionic, 4. Hydrogen bonding D. _______ Which of the following represents an Empirical Formula 1. N2O6 2. C6H12O6 3. C2H4 4. SO3 E. _______Atoms of the Non-metal elements generally form ions by 1. Losing electrons, forming positive ions 2. Losing electrons, forming negative ions 3. Gaining electrons, forming positive ions 4. Gaining electrons, forming negative ions F. _______ The Atomic Mass Unit (AMU) is the mass of 1. A Mole of Carbon 2. A Hydrogen Atom 3. A Carbon Atom 4. An Electron G. _______ A Polar Covalent bond has a 1. Random Charge 2. Positive Charge 3. Negative Charge 4. Dipole H._______ Reaction ratios in gas phase reactions can be measured by 1. Temperature 2. Color 3. Volume 4. Time I. ______ The formula showing the total number of each elements in a chemical formula is the 1. Molecular Formula 2. Atomic Formula 3. Thermodynamic Formula 4. Empirical Formula J. ______ Which of the following would have the highest melting temperature? 1. H2O, 2. CO2 3. SO2 4. MgF2 5. NH3 K. ______ Carbon is very good at forming covalent bonds because 1. It is the best at forming Ionic Compounds 2. Its electronegativity is mid-range 3. Its electronegativity is very large 4. Its electronegativity is very small L. ______ Ionic Compounds 1. Have poor solubility in water 2. Usually have low melting points 3. Conduct electricity when in solution 4. Readily form molecules M. _____ The weakest of the intermolecular forces are: 1. Ionic 2. Covalent 3. Electron sea model 4. Dipole / Dipole 5. London N. _____ Which statement is true about Hydrogen Bonds? 1. They are stronger than covalent bonds 2. They are the weakest of all interactions 3. They are stronger than ionic bonds 4. They are weaker then covalent bonds O. _____ The physical properties of metals result from the inter-particle forces called: 1. Ionic 2. London 3. Electron sea model 4. Covalent 5. Dipole / Dipole P. ______ Ionic compounds dissolve in water because the ions in the compound 1. Attract 2. Repel 3. Negate 4. Dissociate

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Chem 101 / Spring 2017 Name: ______________________________________ Exam 2 // 198pts Lectures H through L (199)

Q. ______ In the kinetic molecular theory gas particles are 1. Far apart 2. Close together 3. Sticky 4. Occupy a large percentage of the volume R. ______ Alkaline earth metals generally form ions with a charge of 1. +1 2. +2 3. -1 4. -2 S. ______ Halogens generally form ions with a charge of 1. +1 2. +2 3. -1 4. -2 T. ______ In the kinetic molecular theory the particle collisions are 1. Sticky 2. Always hard 3. Always soft 4. Elastic 2. Assign the type of chemical bond between the following pairs of atoms as: (A) Ionic, (B) Covalent or (C) Polar Covalent (electronegativity in parenthesis) (9pts)

A. K (0.82) / F (4.0) __________ B. C (2.5) / B (2.0) __________ C. Si (1.9) / O (3.5) _________

3. Correlate each property by entering Ionic or Covalent in the Blank (12pts) A. Soluble in Water: ________________ B. Form Molecules: ________________ C: Often Low Melting Points: ______________ D. Share Electrons _______________ E. Dissociate in water: ________________ F. Solutions Conduct Electricity: _______________

4. For the following: Indicate A. Expected charge for the Cation, B. Expected charge for the Anion and C. Correct formula for the compound formed by the two elements (24pts)

Elements Which is the cation? Include charge

Which is the anion? Include Charge

What is the resulting compound Formula?

S and Mg

Al and Cl

O and Ga

Sr and F

Ca and SO4

Rb and PO4

CO3 and Na

Sr and OH

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Chem 101 / Spring 2017 Name: ______________________________________ Exam 2 // 198pts Lectures H through L (199)

5. Give the Type (I, II or III) and the name of each of the following compounds (34pts)

Compound (3pts ea)

Type (2pts ea)

Charge on Metal (1pts ea)

Name (3pts ea)

PCl5 N/A

Al(NO3)3 Al

TiBr4 Ti

Ca Calcium Sulfate

MnO2 Mn

N/A Carbon Tetrafluoride

6. Give Lewis Dot Structures for the following. Include all Non-Bonded electrons pairs (12pts) A. SiF4 B. PCl3 C. CO2 D. SH2 7. A compound was found to have the following percent composition: C = 24.019%; F = 75.981%

A. What is the Empirical formula of the compound? (6pts) B. If the Molecular Mass was found to be 100.014g/mol, what is the Molecular Formula? (2pts)

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Chem 101 / Spring 2017 Name: ______________________________________ Exam 2 // 198pts Lectures H through L (199)

8. Calculate the Formula mass of the following compounds. (to be used in Problem 9) (9pts) A. C3H6F2 B. SiCl4 C. LiNO3 9. Carry out the following calculations using the formula masses determined in problem 8. Show all work for full credit and make sure to give all units. A. 127.5grams of C3H6F2 is how many moles? (5pts) B. 2.64moles of SiCl4 is how many grams? (5pts) C. What is the percent composition of Li, N and O in LiNO3? Show Work (6pts) %Li: ________________ %N: _______________ %O: ________________

10. The specific heat of Fe is 0.450j/g°C. How much energy is needed to heat a 1.50kg iron pan from 25.0°C to 800.0°C? (5pts)

11. How much energy is required to heat 250.g of water from -10.0°C to 60.0°C? (For water: Specific heat of ice = 2.03 j/g°C; Heat of Fusion is: 334j/g; Specific Heat of liquid water: 4.184j/g°C) (10pts)

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Chem 101 / Spring 2017 Name: ______________________________________ Exam 2 // 198pts Lectures H through L (199)

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