Review of Chemistry I

Review of Chemistry I

types of bonds

balancing equations

electron configurations

moles

Two types of bonds:

• Covalent bonds

• Ionic bonds

Covalent bonds

• the bond between two nonmetals

• sharing of electrons

•  $H_2O$  

• Can have single(2 electrons are shared between two atoms), double(4 electrons are shared between two atoms), or triple(6 electrons are shared between two atoms) bonds

• double bond -  $CO_2$  

• triple bond -  $N_2$  

Ionic Bonds

• transfer of electrons

• between nonmetals & metals

• NaCl

• ion - atom loses or gains gains an electron

•  $Na^+Cl^-$  

Multiple Choice

Salt is an example of what?

• ionic compound

• covalent compound

Multiple Choice

Water is an example of what?

• molecular compound (covalent compound)

• ionic compound

Multiple Choice

Electrons are involved in chemical reactions, not protons or neutrons.

• true

• false

Multiple Choice

How are ionic bonds formed?

• transfer of electrons

• sharing of electrons

Multiple Choice

Atoms are most stable when their outer shell is full or complete.

• true

• false

Multiple Choice

Ionic bonds are between

• metals and nonmetals

• 2 metals

• 2 nonmetals

Multiple Choice

When an atom loses an electron, it becomes a

• positive ion

• negative ion

Multiple Choice

What two types of atoms make a covalent bond?

• 2 nonmetals

• 2 metals

• 1 metal and 1 nonmetal`

Multiple Choice

How do covalent bonds form?

• by sharing electrons between atoms

• by donating or receiving electrons

Multiple Choice

Valence electrons are found

• outermost energy level

• innermost energy level

• some where in the electron cloud

Multiple Choice

Valence electrons are found

• outermost energy level

• innermost energy level

• some where in the electron cloud

Balancing Equations

•  $H_2\ +\ O_2\ ->\ H_2O$  

•  $2H_2\ +\ O_2\ ->\ 2H_2O$  

Multiple Choice

 $Al\ +\ Fe_2O_3\ ->\ Fe\ +\ Al_2O_3$  

Balance the equation:

•  $Al\ +\ Fe_2O_3\ ->\ 2Fe\ +\ Al_2O_3$  

•  $2Al\ +\ Fe_2O_3\ ->\ 2Fe\ +\ Al_2O_3$  

•  $2Al\ +\ Fe_2O_3\ ->\ Fe\ +\ Al_2O_3$  

• already balanced

Multiple Choice

Balance the equation:   $CS_2\ +\ Cl_2\ ->\ CCl_4\ +\ S_2Cl_2$  

•  $CS_2\ +\ 3Cl_2\ ->\ CCl_4\ +\ S_2Cl_2$  

•  $3CS_2\ +\ Cl_2\ ->\ CCl_4\ +\ S_2Cl_2$  

• already balanced

Multiple Choice

Balance the equation:   $NO_2\ +\ O_3\ ->\ N_2O_5\ +\ O_2$  

•  $NO_2\ +\ 2O_3\ ->\ N_2O_5\ +\ O_2$  

•  $2NO_2\ +\ O_3\ ->\ N_2O_5\ +\ O_2$  

• already balanced

Electron Configuration

• Electrons occupy energy levels by filling the lowest level first and continuing to higher energy levels

Multiple Choice

Which element corresponds to the following electron configuration:

 $\left[He\right]2s^22p^4$  

• C

• N

• O

• F

Multiple Choice

Which element corresponds to the following electron configuration?

 $\left[Ne\right]\ 3s^23p^4$  

• Si

• P

• S

• Cl

Fill in the Blank

Write the electron configuration for nitrogen:

Fill in the Blank

Write the electron configuration for beryllium:

Multiple Choice

Within the energy levels around the nucleus, sublevels can be find. The energy sublevels are designated as:

• s,p,d,f

• 2,8,16

• orbitals

Multiple Choice

Within the energy levels around the nucleus, sublevels can be find. The energy sublevels are designated as:

• s,p,d,f

• 2,8,16

• orbitals

Stoichiometry

finding the number of particles to a mass by using dimensional analysis with moles

Moles/ Avogadro's number(constant)

Atoms are so tiny that an ordinary-sized sample of substance contains so many of these submicroscopic particles that counting them by grouping them in thousands would be unmanageable.

Hydrogen

atomic weight - 1.008

one H atom = 1.008 amu

weight of 1 mole of H atoms is 1.008 grams

One mole

 $6.023\ x\ 10^{23}$  particles

Multiple Choice

One mole of the element lead (Pb) contains ________ atoms and weights _________.

• $6.023\ x10^{23}$ atoms & 207.2 g

• 207.2 atoms & $6.023\ x10^{23}$ g

• 207.2 atoms & 207.2 g

• $6.023\ x10^{23}$

Multiple Choice

How many atoms of carbon and sulfur are needed to make one molecule of carbon disulfide?

 $CS_2$  

• two atoms of S; one atom of C

• one atom of C; two atoms of S

• one atom of C; one atom of S

• two atoms of C; two atoms of S

Multiple Choice

To make one mole of carbon disulfide molecules requires how many moles of carbon atoms and sulfur atoms?

• 1 mole of C; 1 mole of S

• 2 moles of C; 1 mole of S

• 1 mole of C; 2 moles of S

Molar Mass

molecular mass = molecular weight = formula mass = formula weight
unit - grams/mole

 $SO_2$  
1 S atom - weighs 32.07 g; 2 oxygen atoms - weigh (2x15.99) 31.98 g
molar mass - 32.07g + 31.98g = 64.05 g/mol
1 mole of sulfur dioxide molecules weights 64.07g

Practice molar mass:

 $Cl_2$  
KOH
Answers:
71 g/mol
56.1 g/mole

Multiple Choice

What is the molar mass of

 $FeCl_3$  

• 55.845 g/mol

• 162.2 g/mol

• 106.359 g/mol

Multiple Choice

What is the molar mass of

 $Mg\left(OH\right)_2$  

• 36.012 g/mol

• 58.3 g/mol

• 24.305 g/mol

Using molar mass as a conversion factor

How many moles of lithium are in 25g of lithium?

molar mass - 6.94 g/mol

3.6 mol Li

What is the mass of 11.5 moles of lithium?

79.8 g Li

Fill in the Blank

How many moles are in 15 grams of lithium?

Fill in the Blank

How many grams are in 2.4 moles of sulfur?

Fill in the Blank

How many moles are in 22 grams of argon?

Fill in the Blank

How many grams are in 88.1 moles of magnesium?