Chemistry Exam 2

Absolute zero, the lowest possible temperature, is exactly 0 K. What is this temperature in °C and °F?

-273.15 °C and -459.67 °F

Convert the following numbers to a number having 2 significant figures: 0.0069330

0.0069

Convert the following numbers to a number having 2 significant figures: 0.47760

0.48

How many significant figures does this number have: 0.006

1

Complete the following calculations and report your answers with the correct number of significant figures: 997.56 + 69.21

1.06677e+3

When one gram of methane gas, CH4(g), is burned, 55.5 kJ of heat are released. How many pounds of methane gas must be burned to release 2.845 ✕ 103 kJ of heat?

1.130e-1

What is the weighted average mass in grams of 6.022 ✕ 1023 atoms of the following elements? : Carbon and Calcium

1.201e1 g & 4.008e g

The average human body contains 5.2 liters of blood. What is this volume in gallons?

1.4 gal

The mass of a proton is 1.6726 ✕ 10−27 kg. What is this mass in nanograms?

1.6726e-15 ng

The mass of a proton is 1.6726 ✕ 10−27 kg. What is this mass in milligrams?

1.6726e-21 mg

Normal blood contains from 3.3 to 5.1 mg of amino acids per 100 mL of blood. If a person has 5.48 L of blood and 3.622 mg of amino acids per 100 mL of blood, how many grams of amino acids does the blood contain?

1.98e-1

How many significant figures does this number have: 0.69

2

A ball of clay has a mass of 2.61 lb and a volume of 0.5669 qt. What is its density in g/mL?

2.21e0 g/mL

A ball of clay has a mass of 2.66 lb and a volume of 0.5489 qt. What is its density in g/mL?

2.32e+0

While you are doing heavy work, your heart pumps up to 25.0 L of blood per minute. What volume of blood in quarts is pumped through your muscles in 147 minutes of work that causes your heart to pump 21.9 L per minute, 79.25% by volume of which goes to your muscles?

2.70e+3

What is the maximum number of electrons that can be placed in the 7h sublevel?

22

What is the maximum number of electrons that can be placed in the 7i sublevel?

26

What is this temperature in K?

290.15

The density of water at 3.98°C is 1.00000 g/mL. What is the mass in pounds of 16.223 L of water?

35.765 lb

Would the electron be more stable in a 3d orbital or in a 5d orbital?

3d

Would the one electron in a hydrogen atom be more strongly attracted to the nucleus in a 3d orbital or in a 5d orbital?

3d

A peanut butter sandwich provides about 1.6 ✕ 103 kJ of energy. A typical adult uses about 95 kcal/hr of energy while sitting. If all of the energy in one peanut butter sandwich were to be burned off by sitting, how many hours would it be before this energy was used? (A kcal is a dietary calorie. There are 4.184 J/cal.)

4.0 hr

One-third cup of vanilla ice cream provides about 148 kcal of energy. A typical adult uses about 191 kcal/hr of energy while walking. If all of the energy in one-third of a cup of vanilla ice cream were to be burned off by walking, how many minutes would it take for this energy to be used? (A kcal is a dietary calorie.)

4.65e1 min

How many significant figures does this number have: 0.76149

5

Which is larger, a 3d orbital or a 5d orbital?

5d

Would the electron have higher potential energy when it is in a 3d orbital or a 5d orbital?

5d

Acetic acid freezes at 17°C. What is this temperature in °F?

6.3e+1 °F

Convert the following ordinary decimal numbers to scientific notation: 64,301, 489,625,159, 0.000040, and 0.0000000416

6.4301e+4, 4.89625159e+8, 4.0e-5, and 4.16e-8

Use your calculator to complete the following calculations. (Enter your answer using one of the following formats: 1.2e-3 for 0.0012 and 1.20e+2 for 120.): (9.6 ✕ 105) ✕ (7.0 ✕ 106)

6.7e+12

Complete the following calculations and report your answers with the correct number of significant figures: 24.03 - 17.2 = ?

6.8e+0

How many orbitals are there in the 5f sublevel for the hydrogen atom?

7

While you are at rest, your brain gets about 15% by volume of your blood. If your body contains 4.7 L of blood, how many liters of blood are in your brain at rest?

7.1e-1 L

While you are at rest, your brain gets about 15% by volume of your blood. If your body contains 4.7 qt of blood, how many liters of blood are in your brain at rest?

7.4e-1 qt

A multivitamin tablet contains 1.4 ✕ 10−4 mole of iron per tablet. How many milligrams of iron does each tablet contain?

7.818e0

What is the maximum number of electrons that can be placed in the second principal energy level?

8

Write the atomic number for each of the following elements: oxygen, Mn, Mg

8, 12, and 25

When one gram of methane gas, CH4(g), is burned, 55.5 kJ of heat are released. How many pounds of methane gas must be burned to release 2.232 ✕ 103 kJ of heat?

8.87e-2 lb

The earth weighs about 1 ✕ 1021 tons. Convert this to gigagrams?(There are 2000. lb/ton.)

9e+17 Gg

Polyatomic ion

A charged collection of atoms held together by covalent bonds.

Molecular compound

A compound composed of molecules. In such compounds, all of the bonds between atoms are covalent bonds.

Ionic Compound

A compound that consists of ions held together by ionic bonds.

Chemical formula

A concise written description of the components of a chemical compound. It identifies the elements in the compound by their symbols and indicates the relative number of atoms of each element with subscripts.

Polar covalent bond

A covalent bond in which electrons are shared unequally, leading to a partial negative charge on the atom that attracts the electrons more and to a partial positive charge on the other atom.

Nonpolar covalent bond

A covalent bond in which the difference in electron attracting ability of two atoms in a bond is negligible (or zero), so the atoms in the bond have no significant charges.

Electron group geometry

A description of the arrangement of all the electron groups around a central atom in a molecule or polyatomic ion, including the lone pairs.

Double bond

A link between atoms that results from the sharing of four electrons. It can be viewed as two 2‑electron covalent bonds.

Triple bond

A link between atoms that results from the sharing of six electrons. It can be viewed as three 2‑electron covalent bonds.

Lewis structure

A representation of a molecule that consists of the elemental symbol for each atom in the molecule, lines to show covalent bonds, and pairs of dots to indicate lone pairs.

Electron-dot symbol

A representation of an atom that consists of its elemental symbol surrounded by dots representing its valence electrons.

Mixture

A sample of matter that contains two or more pure substances and has variable composition.

Pure substance

A sample of matter that has constant composition. There are two types of pure substances, elements and compounds.

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Which element is associated with the ground state electron configuration listed: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2

Barium

Alcohols

Compounds that contain a hydrocarbon group with one or more -OH groups attached.

Hydrocarbons

Compounds that contain only carbon and hydrogen.

Isomers

Compounds that have the same molecular formula but different molecular structures.

Decide whether these numbers are exact or not and convert them using significant figures: The 40% of halogens that are gases at normal room temperature and pressure (determined by counting 2 gaseous halogens out of the total of 5 halogens and then calculating the percentage).

Exact Number

Decide whether these numbers are exact or not and convert them using significant figures: The count of 114 symbols for elements on a periodic table.

Exact Number

If a parent stops pushing a swinging child, why does the child eventually stop? Where has the energy of the swinging child gone? _____energy is transferred from the_____to the______in addition to being transferred from the chain to the swing structure.

Kinetic energy is transferred from the child to the air particles in addition to being transferred from the chain to the swing structure. in addition to being transferred from the chain to the swing structure.

Monatomic anions

Negatively charged particles, such as Cl-, O2-, and N3-, that contain single atoms with a negative charge.

Which element is associated with the ground state electron configuration listed: 1s^2 2s^2 2p^3

Nitrogen

Decide whether these numbers are exact or not and convert them using significant figures: 3.480 × 10^3 km?

Not exact and 4

Monatomic cations

Positively charged particles, such as Na+, Ca2+, and Al3+, that contain single atoms with a positive charge.

Bond angle

The angle formed by straight lines (representing bonds) connecting the nuclei of three adjacent atoms.

Ionic bond

The attraction between a cation and an anion

Organic chemistry

The branch of chemistry that involves the study of carbon-based compounds.

Molecular geometry

The description of the arrangement of all the atoms around a central atom in a molecule or polyatomic ion. This description does not consider lone pairs.

Valence electrons

The electrons that are most important in the formation of chemical bonds. The number of valence electrons for the atoms of an element is equal to the element's A-group number on the periodic table. The highest energy s and p electrons for an atom.

Trigonal planar (often called triangular planar)

The geometric arrangement that keeps three electron groups as far apart as possible. It leads to angles of 120° between the groups

Linear geometry

The geometric arrangement that keeps two electron groups as far apart as possible. It leads to angles of 180° between the groups.

Trigonal pyramid

The molecular geometry formed around an atom with three bonds and one lone pair.

Bent

The molecular geometry formed around an atom with two bond groups and two lone pairs or two bond groups and one lone pair.

Tetrahedral

The molecular shape that keeps the negative charge of four electron groups as far apart as possible. This shape has angles of 109.5° between the atoms.

Lone pair

Two electrons that are not involved in the covalent bonds between atoms but are important for explaining the arrangement of atoms in molecules. They are represented by pairs of dots in Lewis structures.

Identify each of the following as a cation or an anion, and determine the charge on each: A sulfur ion with 16 protons and 18 electrons

Type: anion & Charge: -2

Identify each of the following as a cation or an anion, and determine the charge on each: An oxygen ion with 8 protons and 10 electrons

Type: anion & Charge: -2

When a child swings on a swing, energy is constantly being converted back and forth between kinetic energy and potential energy. At what point in the child's motion is the potential energy at a maximum?

When the swing is at its highest position.

Write the abbreviated electron configurations for Cobalt?

[Ar]4s^2 3d^7

Write the abbreviated electron configurations for Flourine?

[He]2s^2 2p^5

Write the abbreviated electron configurations for Indium?

[Kr]5s^2 4d^10 5p^1

The wave view says that as radiant energy moves away from its source, it has an effect on the space around it that can be described as a wave consisting of an oscillating______field perpendicular to an oscillating_____field.

electric & magnetic

After the electron is excited from the 1s orbital to the 2s orbital, it_____________________to its lower-energy 1s form.

spontaneously returns

Orbitals that have the same potential energy, the same size, and the same shape are in the same_______.

sublevel

Chemical bond

An attraction between atoms or ions in chemical compounds. Covalent bonds and ionic bonds are examples.