Chemistry

Use this to change kilometers to meters with one conversion factor.

Use this to change a speed in kilometers per hour to meters per second.

Use this to read a rod’s length from its start and end, to one digit past the smallest marks.

Use this to judge a set of trials against the accepted value and find the percent error.

Use this to find an ion’s charge from its protons and electrons, or the electrons from its charge.

Use this for “Boron is 19.9% boron-10 (10.01 u) and 80.1% boron-11 (11.01 u). Find its atomic mass.”

Use this for “How did the model of the atom change, and what evidence changed it?”

Use this for an ion’s configuration, such as Fe³⁺: electrons taken from the highest shell first.

Use this for the energy and wavelength of the light a hydrogen atom gives off when its electron drops a level.

Use this for the frequency and energy of a photon from its wavelength.

Use this to compare how much energy it takes to pull an electron off two atoms.

Use this to see which atom in a bond pulls the shared electrons harder.

Use this for “Which family is potassium in, and what does it share with sodium?”

Use this to find an ionic compound’s formula from the charges of its ions: Mg²⁺ with Cl⁻ is MgCl₂, Al³⁺ with O²⁻ is Al₂O₃.

Use this for metallic bonding: how many electrons a piece of aluminum shares among its ions.

Use this to tell whether a bond is nonpolar, polar covalent or ionic from the electronegativity difference.

Use this for “Which observation shows that a solid is an ionic compound?”

Use this for “What kind of bond holds magnesium oxide together?”

Use this for “Is carbon tetrachloride polar, even though its bonds are?”

Use this for “Which liquid evaporates faster, and which has the higher boiling point?”

Use this for “Why does ice float on liquid water?”, “How many hydrogen bonds can one water molecule make?” or “Why does water dissolve salt?”

Use this to balance any alkane burning, such as “C₃H₈ + O₂ → CO₂ + H₂O”: carbon first, hydrogen next, oxygen last.

Use this to balance an alkene burning, such as “C₅H₁₀ + O₂ → CO₂ + H₂O”: with an odd number of carbons the fuel’s coefficient is 2.

Use this for “Balance Al + O₂ → Al₂O₃.”

Use this for “Balance Zn + HCl → ZnCl₂ + H₂.”

Use this for “Does zinc react with copper(II) sulfate, and what does it make?”

Use this for a compound’s molar mass and the percent of its mass from each element.

Use this for “How many moles are in 22 g of CO₂ (44.01 g/mol)?”

Use this for “How many moles, grams and molecules are in 11.2 L of O₂ at STP?”

Use this to find the simplest whole-number formula from the percent of each element.

Use this to find which reactant runs out first, how much product forms and what is left over.

Use this for “28.01 g of N₂ and 5.05 g of H₂ react. How many grams of NH₃ form?”

Use this for the percent yield from the actual and theoretical masses of product.

Use this for a gas squeezed or let out at one temperature: “6 L at 1 atm is pressed into 3 L. What is the pressure?”

Use this for a gas warmed or cooled at one pressure: “2.00 L at 300 K is heated to 450 K. What is its volume?”

Use this for a gas heated in a rigid container: “A tire at 2.00 atm and 280 K warms to 308 K. What is the pressure?”

Use this when pressure, volume and temperature all change: “5.00 L at 1.00 atm and 300 K goes to 2.00 atm and 360 K. What is the volume?”

Use this for “Helium (4.00 g/mol) and argon (39.95 g/mol) leak from one tank. Which escapes faster, and how many times as fast?”

Use this for a mixture of gases: the total pressure from each gas’s partial pressure, and one gas’s mole fraction.

Use this for “0.5 mol of glucose is dissolved in 9.5 mol of water at 25 °C. How much does the vapor pressure drop?”

Use this for “Why does an egg take longer to cook in boiling water high on a mountain?”

Use this for “Is freezing endothermic or exothermic?”

Use this for “5.844 g of NaCl (58.44 g/mol) makes 250 mL of solution. What is the molarity?”

Use this for “How much 2.00 M stock makes 200 mL of 0.500 M, and how much water is added?”

Use this for “50 g of KNO₃ is stirred into 100 g of water at 40 °C. Is it saturated?”

Use this for “15 g of sugar is dissolved in 135 g of water. What is the percent sugar by mass?”

Use this for “A reaction warms 100 g of water from 21 °C to 27.5 °C. How much heat did it give off?”, or a metal’s specific heat from its heat, mass and warming.

Use this for the ΔH per mole of a salt that cools the water as it dissolves.

Use this for the heat to take ice all the way to steam: warm it to 0 °C, melt it, warm the water to 100 °C and boil it away.

Use this for ΔH of this reaction, CH₄ + 2O₂ → CO₂ + 2H₂O, from the heats of formation.

Use this for ΔH of this reaction, C + O₂ → CO₂, from C + ½O₂ → CO and CO₂ → CO + ½O₂.

Use this for “Above what temperature is a reaction with ΔH = 60 kJ/mol and ΔS = 150 J/(mol·K) spontaneous?”

Use this for “The products’ standard entropies add to 214 J/(mol·K) and the reactants’ to 188; ΔH° = −50 kJ/mol. What are ΔS° and ΔG° at 298 K?”

Use this for “Predict the sign of ΔS when a gas forms from a solid.”

Use this for “A reaction has ΔH > 0 and ΔS > 0. When is it spontaneous?”

Use this for “H₂ is added to H₂ + I₂ ⇌ 2HI at equilibrium. Which way does it shift?”

Use this for how much a catalyst lowers the activation energy, forward and back.

Use this for “[A] falls from 1.20 mol/L at 30 s to 0.75 mol/L at 120 s. What is the average rate?”

Use this for AgCl, a salt that barely dissolves: its Ksp from its molar solubility, or the solubility from Ksp.

Use this for “N₂ + 3H₂ ⇌ 2NH₃ gives off heat. Which way does it shift when it is cooled?”

Use this for “Why does a crushed antacid tablet fizz faster than a whole one?”

Use this for “A solution has a pH of 8.50. What is its [H⁺]?”

Use this for “A solution of 0.010 M NaOH: what are its pOH and pH?”

Use this for “25 mL of 0.1 M HCl is titrated with 0.2 M NaOH. Where is the equivalence point?”

Use this for “20 mL of 0.1 M acetic acid (Kₐ = 1.8 × 10⁻⁵) is titrated with 0.1 M NaOH.”

Use this for “Is baking soda solution an acid, a base or neutral?”

Use this for “What voltage does a zinc–copper cell give?”: E°cell from the two metals’ reduction potentials.

Use this for “What is the oxidation number of S in H₂SO₄?” or in SO₄²⁻.

Use this for “In Zn + Cu²⁺ → Zn²⁺ + Cu, which substance is oxidized?”

Use this for “How is an electrolytic cell different from a battery?”

Use this for an alkene’s formula and name: a chain with one carbon–carbon double bond, CₙH₂ₙ.

Use this for an alkyne’s formula and name: a chain with one carbon–carbon triple bond, CₙH₂ₙ₋₂.

Use this for “Draw an isomer of pentane” or “How many hydrogens does 2-methylbutane have?”

Use this for “Which functional group does ethyl acetate have?”

Use this for “Is nylon an addition polymer or a condensation polymer?”

Use this for “Uranium-238 gives off an alpha particle. What nucleus is left?”

Use this for “Carbon-14 gives off a beta particle. What nucleus is left?”

Use this for “U-235 takes in a neutron and splits into Ba-141, a second nucleus and 3 neutrons. What is the second nucleus?”

Use this for “U-238 gives off an alpha particle. How much mass is lost, and how much energy is released?”

Use this for “Which equation shows fission?” and “Why is fusion a cleaner source of energy than fission?”