Chemistry Flashcards
(30 cards)
What is the definition of a mole in chemistry?
A mole is defined as the amount of substance that contains as many entities (atoms, molecules, etc.) as there are atoms in 12 grams of carbon-12.
True or False: The molar mass of an element is the mass of one mole of that element in grams.
True
What is the formula to calculate the number of moles?
Number of moles = mass (g) / molar mass (g/mol)
Fill in the blank: The empirical formula represents the _________ ratio of atoms in a compound.
simplest
What is the difference between an empirical formula and a molecular formula?
An empirical formula shows the simplest whole-number ratio of atoms, while a molecular formula shows the actual number of atoms of each element in a molecule.
Which law states that mass is neither created nor destroyed in a chemical reaction?
The Law of Conservation of Mass
What is the pH scale used for?
The pH scale is used to measure the acidity or basicity of a solution.
What is the pH of a neutral solution at 25°C?
7
True or False: Acids have a pH less than 7.
True
What is the general formula for calculating pH?
pH = -log[H+]
What is an acid-base titration?
An acid-base titration is a method used to determine the concentration of an acid or base by reacting it with a solution of known concentration.
What is the endpoint in a titration?
The endpoint is the point at which the reaction is complete, often indicated by a color change.
Fill in the blank: A catalyst is a substance that __________ the rate of a chemical reaction without being consumed.
increases
What is the purpose of a catalyst in a chemical reaction?
To lower the activation energy and increase the rate of the reaction.
What are the four main types of chemical reactions?
Synthesis, decomposition, single replacement, and double replacement.
True or False: In a synthesis reaction, two or more substances combine to form a single product.
True
What is the law of definite proportions?
The law of definite proportions states that a chemical compound always contains its component elements in fixed ratio by mass.
What is the formula for calculating concentration?
Concentration (mol/L) = moles of solute / volume of solution (L)
What does the term ‘oxidation’ refer to in a chemical reaction?
Oxidation refers to the loss of electrons or an increase in oxidation state.
Fill in the blank: Reduction is the _________ of electrons.
gain
What is a redox reaction?
A redox reaction is a chemical reaction involving the transfer of electrons between two species.
What is the role of an oxidizing agent?
An oxidizing agent is a substance that gains electrons and is reduced in a chemical reaction.
What is the ideal gas law?
The ideal gas law is PV = nRT, where P is pressure, V is volume, n is number of moles, R is the ideal gas constant, and T is temperature in Kelvin.
True or False: The ideal gas law applies to all gases under all conditions.
False
