Molecular Fun-ula
Calculate the molar mass of Mg(NO3)2
148.3 grams (+/- 2 g)
7 - Hepta
What are compound that come before the arrow in a reaction called and what are compounds that come after the arrow called?
Reactants --> Products
(Reactants react to produce new things)
Where are protons, neutrons, and electrons found in an atom?
(Hint, think of the activity we did with the black and white atomic models)
Protons and Neutrons - Found in the nucleus
Electrons - Found floating around in shells around the nuclues
Draw the lewis dot structure for phosphorus
There should be a P in the middle with 5 dots around it to represent its 5 valence electrons
Calculate the percent composition of nitrogen in Mg(NO3)2
18.9%
What is the name of the compound N2O5?
N2O5 - Dinitrogen pentoxide
What does it mean that mass is conserved in a reaction?
While things might change in a reaction, the total mass of all compounds before a reaction equals the total mass of all compounds after the reaction.
Why is air not considered a pure substance?
Air is composed of various gases such as oxygen, carbon dioxide, nitrogen, argon, helium, etc.
What is the largest atom on the periodic table?
Francium
(Remember as we go down, atoms get bigger and as we move from left to right they get smaller so the bottom left corner has the biggest atoms and the top right has the smallest)
a. C2H5
b. C2H8
c. C2H4
d. C4H10
What is the name of the compound AlCl3?
Aluminum Chloride
What is the coefficient for sodium when the following reaction is balanced?
___ NaN3 --> ___ Na + ___ N2
_2_ NaN3 --> _2_ Na + _3_ N2
The coefficient for sodium is 2
Why are gases easily compressible?
Their molecules are far apart and they have weak intermolecular forces between each other
Which element shares chemical and physical properties with chlorine and why?
a. Br - it is in the same group as chlorine
b. P - it is in the same period as chlorine
c. C - it has a similar chemical symbol to chlorine
d. Xe - it is also a gas at room temperature
Br - it is in the same group as chlorine
(Families always share chemical and physical properties since they gain or lose the same amount of electrons when they react)
The molar mass of a molecule is found to be 138.00 g/mol. What is the molecular formula of the molecule if its empirical formula is NO2?
a. NO
b. N2O4
c. N2.5O
d. N3O6
The molar mass of NO2 is 46.00 g/mol. To get it to 138, we have to triple that mass so we triple the entire compound to get d. N3O6
What is the correct name for SnO2?
a. Selenium Oxide
b. Selenium (II) Oxide
c. Tin Oxide
d. Tin (IV) Oxide
SnO2
d. Tin (IV) Oxide
(Remember, tin is considered a transition metal so needs parenthesis in the name)
What is the coefficient for bromine when the following reaction is balanced?
___ P4 + ___ Br2 --> ___ PBr3
_1_ P4 + _6_ Br2 --> _4_ PBr3
The coefficient for bromine is 6
Why are metals such good conductors of heat and electricity?
They have free moving electrons in a "sea of electrons"
An unknown element was recently discovered and found to have the characteristics shown in the table below. In which group/family does the unknown element most likely belong?
- Shares 1 electron to obtain a stable gas configuration
- Is very reactive
- Is a gas at room temperature
- Readily forms salts
The element is likely a halogen
(Tips: Narrow it down to the non-metals since it's a gas or focus on the charge/valence electrons since those will be noted on your periodic table)
How many atoms are found in 3 moles of Copper?
Remember there are 6.024 x 1024 atoms per mole in every substance. Therefore if we have 3 moles, we can simply multiply 3 times 6.024 x 1024
(This number is going to be in your reference materials so you don't have to remember it!)
Write the formula for the compound Copper (II) Nitrate?
a. Cu(NO3)2
b. Cu2NO3
c. CuNO3
d. Cu2(NO3)2
Copper (II) Nitrate
- Cu(NO3)2
What is the coefficient for O2 when the following reaction is balanced?
___ C2H6 + ___ O2 --> ___ CO2 + ___ H2O
a. 4
b. 5
c. 6
d. 7
d. 7
What is the average atomic mass of the following element?
Isotope : Mass : Percent Abundance
X-54 : 53.9 amu : 11.0 %
X-57 : 57.0 amu : 82.5 %
X-60 : 60.3 amu : 6.50 %
56.87 amu
What is the electron configuration of the element Arsenic?
a. 1s22s22p63s23p63d104s24p3
b. 1s22s22p63s23p64s23d104p3
c. 1s22s22p63s23p64s23d104p6
d. 1s22s22p63s23p64s23d64p6
b. 1s22s22p63s23p64s23d104p3
(Tips: The numbers at the top should add up to the number of electrons, 33. The order is read like a book, left to right, then next line, and so on)