Isotopes and average atomic mass
Dimensional Analysis
Stoichiometry
Solutions
Acids and Bases
100
Two isotopes of an element must differ in number of _____________.
a. protons
b. neutrons
c. electrons
d. shells
B
100
What is Avogadro's number?
6.02 x 1023
100
What is the name of the leading number in front of a chemical compound in a reaction (ex: the 2s in 2H2 + O2 --> 2H2O)?
coefficient
100
What are the two parts of every solution?
solute and solvent
100
What is the relationship between the [H+] and [OH-] in a sample of pure water?
equal
200
How many neutrons does the following isotope of iodine contain?
I-125
72
200
What is the gram formula mass (molar mass) of C2H4 rounded to the hundredths place?
28.06 g/mol
200
What is the mole ratio between N2 and NH3 in the Haber reaction below?
N2 + 3H2 --> 2NH3
1:2
200
What is the maximum mass of sucrose that can be dissolved in 100 mL of water at 60oC?
~280 g
200
Which of the following is an arrhenius acid?
a. NaOH
b. NaCl
c. C2H4
d. HF
D
300
Gallium has only two stable isotopes: Ga-69 and Ga-71. The average atomic mass of gallium is 69.72 amu. Gallium-based LEDs contain a mixture of these two naturally occurring isotopes. Based on its average atomic mass, which isotope is more prevalent in a gallium LED?
a. Ga-69
b. Ga-71
c. both contribute equally
d. impossible to know with the given information
A
300
Convert 12 g of water to moles of water. Round to the hundredths place.
0.67 moles
300
How many moles of ammonia (NH3) are produced when 4.2 moles of H2 react with excess N2?
N2 + 3H2 --> 2NH3
2.8 moles of NH3
300
What is the molarity of an NaCl (aq) solution when 58.44 g of NaCl is dissolved in a 0.5 L solution?
2 M
300
Finish the neutralization reaction and balance.
H2SO4 + KOH -->
H2SO4 + 2KOH --> 2H2O + K2SO4
400
List the # of protons, neutrons, and electrons in a chloride ion (Cl-) with a mass number of 36
protons -17
neutrons - 19
electrons -18
400
Convert 3.40 moles of NaCl to grams of NaCl. Round to the nearest whole number.
199 g
400
2 NaCl → 2 Na + Cl2
How many grams of sodium chloride (NaCl) are required to make 0.32 moles of chlorine (Cl2)?
37 g NaCl
400
What is the concentration in parts per million of an AgCl(aq) solution that contains 1.2 x 10-3 grams of AgCl in 800. grams of the solution?
1.5 ppm
400
What is the [H+] of a substance with a known [OH-] of 3.4 x 10-10?
2.9 x 10-5 M
500
Calculate average atomic mass and identify the element using a periodic table based on the following data:
Isotope 1:
68.926 amu, 60.11% abundance
Isotope 2: 70.925 amu, 39.89% abundance
69.72 amu, Gallium (Ga)
500
How many molecules of water are in 230 g of water?
7.7 x 1024 molecules
500
2 Ga2O3 → 4 Ga + 3 O2
How many grams of oxygen (O2) can be produced from 15.2 grams of gallium oxide (Ga2O3)?
3.89 g
500
If 25.0 mL of a 2.19 M solution are diluted to 72.8 mL, what is the final concentration?
0.752 M
500
Calculate the [OH-] of a solution with a known pH value of 5.6.
4.0 x 10-9 M