Moles & Formulas
What is the molar mass of oxygen?
15.999g/mol
What do each of the following state labels mean:
(aq)
(s)
(l)
(g)
aqueous - dissolved in water
solid
liquid
gas
At home, you decide to make a peanut butter and jelly sandwich.
You use 2 slices of bread, 2 scoops of jelly, and 1 scoop of peanut butter.
What is the ratio of ingredients needed to make this sandwich?
2:2:1
Describe the difference between exothermic and endothermic reactions
Exo - heat leaves the system and goes into the surroundings
Endo - heat enters the system from the surroundings
What is pH?
A measure of how acidic or basic a substance is
How many mols are in 3.4g of boron?
0.31mol
What are subscripts and how are they used when writing chemical formulas?
Subscripts show how many atoms of each element are in a molecule. They are used to make compounds "happy" by balancing ionic charges
Define the term limiting reactant
The reactant you run out of when doing a chemical reaction. Determines how much product you make
The specific heat of water is 4.18 J/g℃ while the specific heat of aluminum is 0.9 J/g℃. Which substance will require more heat energy to increase its temperature by 10℃?
Water
What is molarity?
What is the chemical name of this covalent compound: H2O
dihydrogen monoxide
What type of chemical reaction is shown below:
K + NaCl --> KCl + Na
Single replacement
4Al + 3O2 --> 2Al2O3
How many moles of aluminum oxide would be produced from 22.1mol of O2?
14.7mol of Al2O3
After an experiment, you calculate that the q value in the chemical reaction was -319J. What does this tell you about the reaction?
It was an exothermic reaction that released -319J of heat energy into the surroundings
Classify each of the following chemicals as an Arrhenius acid or base:
HNO3
Mg(OH)2
KOH
BrH
HNO3 - acid
Mg(OH)2 - base
KOH - base
BrH - acid
Ethene is a chemical made of 2 carbons and 4 hydrogens. What is ethene's molecular and empirical formula?
Molecular: C2H4
Empirical: CH2
Balance the following equation:
Al + HCl --> AlCl3 + H2
2Al + 6HCl → 2AlCl3 + 3H2
HCl + NaOH --> NaCl + H2O
How many grams of water is produced if 6.43mol of hydrogen chloride is used?
115.84g of H2O
Define each of the following:
Convection -
Conduction -
Radiation -
Convection - heat transfer in gasses and liquids due to the movement of heated particles
Conduction - heat transfer through direct contact
Radiation - heat transfer in waves without direct contact
The equation for molarity is M = moles/liters
Calculate the molarity of a solution made by dissolving 2.31 moles of NaOH into 0.750L of solution
3.08M
You have a 16.3L sample of nitrogen gas (N2) at STP. How much does it weigh?
20.4g
Finish the single replacement reaction below. Then balance it (TIP: check for diatomic elements!):
AlI3 + F2 -->
2AlI3 + 3F2 → 2AlF3 + 3I2
Zn + 2HCl --> ZnCl2 + H2
If 4.81x1023 particles of Zn is used, how many liters of H2 will be made?
17.9L of H2
Calculate the specific heat capacity of a piece of wood if 1253g of the wood absorbs 4383J of heat, and its temperature changes from 32°C to 53°C.
0.17J/g°C
In the following equation, identify which reactant is the Brønsted-Lowry acid (TIP: it has to do with the Hydrogen)
HCl + H2O --> Cl- + H3O
HCl because it donates/gives up a Hydrogen