Atoms, Elements, & Compounds
The atomic number is equal to the number of ______.
Protons
Why do Li, Na, and K have similar chemical properties?
What two conversion factors can you write from the following molarity? 1.3 M NaOH
1.3 mols NaOH/ 1 L NaOH
OR
1 L NaOH/ 1.3 mols NaOH
As volume increases, pressure _______.
decreases
Which of the following visible colors of light has the longest wavelength?
a. blue
b. green
c. yellow
d. red
d. red
Write the chemical formula for the compound that forms when calcium and chlorine bond.
CaCl2
Balance the following reaction:
_____ CH4O+ _____ O2 → _____ CO2 + _____ H2O
2,3,2,4
Determine the molarity of a solution formed by dissolving 468 mg of MgI2 in enough water to yield 50.0 mL of solution
0.0337 M
At STP, 1 mole of any gas occupies 22.4 L. Prove this mathematically, using PV=nRT.
Kayla will write this on the board!
The sign of ΔH for an endothermic reaction is _____, since endothermic reactions _____ heat.
a. negative; absorb
b. positive; absorb
c. negative; release
d. positive; release
b. positive; absorb
Write the name for Sn(SO4)2
tin (IV) sulfate
Write the balanced equation for the fermentation of sucrose (C12H22O11), in which aqueous sucrose reacts with water to produce aqueous ethanol (C2H5OH) and CO2 gas. Be sure to include states!
C12H22O11 (aq)+ H2O (l) → 4 C2H5OH (aq) + 4CO2 (g)
Give the complete ionic equation for the reaction that occurs when aqueous solutions of sodium sulfide and iron(II) nitrate are mixed. Clearly label the precipitate (if any).
2 Na+(aq) + S2-(aq) + Fe2+(aq) + 2 NO3-(aq) → FeS(s) + 2 Na+(aq) + 2 NO3-(aq)
What pressure will 14.0 g of CO exert in a 3.5 L container at 75°C?
4.1 atm
Determine the final temperature of a gold nugget (mass = 376 g) that starts at 45°C and loses 4.85 kJ of heat to a snowbank when it is lost. The specific heat capacity of gold is 0.128 J/g°C.
Tf = -56 °C
What is the charge on the Fe ions in Fe2O3
3+
Magnesium burns in air to produce magnesium oxide:
2 Mg(s) + O2(g) → 2 MgO(s)
When 5.00 g of magnesium burns, the theoretical yield of magnesium oxide is ________ g.
8.29 g
What element is undergoing reduction (if any) in the following reaction?
Zn(s) + 2 AgNO3(aq) → Zn(NO3)2(aq) + 2 Ag(s)
Silver (Ag)
Determine the volume of O2 (at STP) formed when 50.0 g of KClO3 decomposes according to the following reaction. The molar mass for KClO3 is 122.55 g/mol.
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
13.7 L
Use Hess's Law and the enthalpies given below to determine ΔH°rxn for the following reaction:
P4(g) + 10 Cl2(g) → 4 PCl5(s) ΔHrxn = ?
Given:
PCl5(s) → PCl3(g) + Cl2(g) ΔH1 = +157 kJ
P4(g) + 6 Cl2(g) → 4 PCl3(g) ΔH2 = -1207 kJ
ΔH°rxn = -1835 kJ
How many moles of C5H12 contain 9.25 × 1024 molecules of C5H12 ?
15.4 moles
The density of ethanol, C2H5OH, is 0.789 g/mL. How many mL of ethanol are needed to produce 25.0 g of CO2 according to the following chemical equation?
C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l)
16.6 mL
The titration of 80.0 mL of an unknown concentration H3PO4 solution requires 126 mL of 0.218 M KOH solution. What is the concentration of the H3PO4 solution (in M)?
(Hint: You'll need to write a balanced equation)
0.114 M
What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO2 at 398 K?
46.6 atm
Use the ΔHf° information provided to calculate ΔHrxn° for the following:
SO2Cl2(g) + 2 H2O(l) → 2 HCl(g) + H2SO4(l)
ΔHf° (kJ/mol):
SO2Cl2(g) = -364
H2O(l) = -286
HCl(g) = -92
H2SO4(l) = -814
ΔHrxn° = -62kJ