The Beginning
Chemistry Math
Good Questions for Good Students
"Hard" Stuff
Fun Questions I Like
100
Which subatomic particle determines the charge of an atom or compound?
The electron
100
There are two isotopes of a compound, one which weighs 54g and one which weighs 55g. The 54g isotope is 37.5% abundant in nature. What is the molecular weight of the compound?
54.625 g
100
Provide an example of an element that has at least 1 electron in the 3s subshell.
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and so on
100
What are the bond angles for a trigonal planar molecule?
120°
100
Why is MgO an ionic compound, whereas CO is not?
Mg is an alkaline earth metal and oxygen is a nonmetal. Ionic compounds require the two atoms bonded to be a metal and a nonmetal. They require this because of the massive difference in electronegativity.
200
If an element from group 1 were to bond with an element from group 7, what kind of bond is occurring?
An Ionic Bond
200
In the formation of methanol (CH3OH), hydrogen combines with carbon monoxide. If 24.67 g of hydrogen and 17.3 g of carbon dioxide are used in this reaction, how many grams of methanol can be formed?
19.79 g methanol
200
What is the formula to find the bond energy of a reaction?
Sum bonds broken - sum of bonds formed
200
The central atom of a compound has 5 bonding/electron groups surrounding it. What is the hybridization of the central atom?
dsp³
200
Why must all six atoms of C₂H₄ be in the same plane?
The two C atoms are connected by a double bond which is not able to rotate. This holds the single bonds to the hydrogens in place within the same plane.
300
How many atoms are contained within 4.58 g of SO₃?
3.445E22 atoms
300
Calculate the frequency of a photon absorbed when a hydrogen atom experiences a transition from n=2 to n=4.
6.17E14 Hz
300
Which of the following is not a possible mₗ value for n=2: -1, 1, 2?
2
300
Will the following reaction form a precipitate? What are the products of the reaction? CaCl₂ + Na₂SO₄
Yes, CaSO₄ will precipitate out. The full reaction is: CaCl₂ + Na₂SO₄ → 2NaCl + CaSO₄
300
What volume of 0.0200 M calcium hydroxide in mL is required to neutralize 35 mL of 0.0500 M nitric acid?
43.75 mL
400
What is the formula for potassium permanganate?
KMnO₄
400
What is the empirical formula for a compound containing 31.5% Al, 56.1% O, and 12.4% S by mass?
Al₃O₉S
400
Name the following compound: HCO₃⁻.
Bicarbonate or hydrogen carbonate
400
DAILY DOUBLE
400
A 450.0 mL sample of a 0.257 M solution of silver nitrate is mixed with 400.0 mL of 0.200M calcium chloride. What is the concentration of Cl₂ in solution after the reaction is complete?
0.0434 M
500
The blue color of fireworks is often achieved by heating copper (I) chloride to 1200℃. Then, the compound emits a blue light which has a wavelength of 450 nm. What is the quanta of energy emitted by this process?
4.41E-19 J
500
Determine the bond order for C₂⁻. Is it paramagnetic or diamagnetic?
5/2, paramagnetic
500
Order the following ions from smallest to largest atomic radius: Ca²⁺, Br⁻, Al³⁺, K⁺, and O²⁻
Al³⁺ < Ca²⁺ < K⁺ < O²⁻ < Br⁻
500
Balance the following redox reaction: PbO + NH₃ → N₂ + Pb.
3PbO + 2NH₃ → N₂ + 3Pb + 3H₂O
500
After balancing the following redox reaction, what is the sum of all coefficients? Cu²⁺ + Ce³⁺ → CeO₂ + Cu
Cu²⁺ + 2Ce³⁺ + 4H₂O → 2CeO₂ + Cu + 8H⁺
Sum: 18