Chemical Rxns
What are coefficients in a balanced equation?
The number of moles of a substance it takes for the reaction to go to completion.
What is the relationship between moles and molarity?
Molarity = mol/L
Define what a precipitate is.
Solid insoluble product in a solution.
What is the energy equation for a photon?
E=hv
List 3 soluble and 3 insoluble compounds.
Define reactants and products in a chemical reaction.
Reactants= what is reactant/starting materials
Products = what is produced/ending materials
If 3 moles of substance A react, how many moles of product B are produced? Given 3 A → 2 B
3 moles * (2 moles B/ 3 moles A) = 2 moles B
What is the solubility rule for sulfates?
Soluble with exceptions including BaSO₄, PbSO₄, and CaSO₄.
What is the shape of an s orbital?
Sphere
Convert 480 nm to m.
480 nm = 4.80×10−74.80×10−7 m.
Explain the law of conservation of mass in terms of balancing reactions
The amount of reactants on the left side of the equation must equal the amount of products on the right side. (The equation must be balanced).
How do you determine the limiting reactant in a reaction?
Determine the theoretical yield based on all the reactants. Whichever one gives you the smallest amount is the limiting reactant.
What is the difference between a substance being an electrolyte and being soluble?
Electrolytes dissociate to form ions and conduct electricity. Soluble substances do not conduct electricity.
Describe what an orbital is in quantum mechanics.
Where the electrons "live." This is where the electrons move around and interact with each other, and/or are most likely to be.
What is the percent yield if the theoretical yield is 50 g and the actual yield is 45 g?
Percent yield = actual yieldtheoretical yield×100theoretical yieldactual yield×100
Percent yield = 45 g50 g×100=90%50g45g×100=90%
What type of reaction is NaCl + AgNO₃ → AgCl + NaNO₃?
Precipitation Reaction and Double Replacement.
Calculate the grams of product formed from 10 g of A in the reaction 2A + 3B → C + 2D. (MM A=15 g/mol, MM B = 20 g/mol, MM D = 25 g/mol)
Given 10 g of A (molar mass = 15 g/mol) and 10 g of B (molar mass = 20 g/mol), you would calculate the moles and then use stoichiometry to find grams of D produced (molar mass = 25 g/mol)
10 g A (1 mol/15 g A) (2 mol D/ 2 mol A)(25 g D / 1 mol D)= 16.7 g = 17 g D
What is a strong electrolyte?
A strong electrolyte completely dissociates into ions in solution. Example: NaCl.
What does wave-particle duality mean?
Electrons exist and behave as both a particle and a wave unless observed and forced to take on the attributes of one or the other.
What are the oxidation states of elements in H₂O?
The oxidation states in H₂O are: H = +1, O = -2.
What is the balanced equation for the combustion of methane?
CH4 + 2O2 → CO2 + 2H2O
How many moles of O₂ are needed to react with 4 moles of CH₄ in the combustion reaction?
To react 4 moles of CH₄, you need 8 moles of O₂ (using the equation from above).
What is the molarity of 5 g of NaCl in 250 mL of solution?
Molarity of 5 g of NaCl in 250 mL:
Molarity=5 g 58.44 g/mol×0.25 L≈0.34M
What is the significance of the principal quantum number (n)?
n (principle QN) tells us the size and energy level of the atom.
What is the empirical formula for C₆H₁₂?
The empirical formula for C₆H₁₂ is CH₂.