cardio physio mcq

What is stoichiometry?

The study of the quantitative relationships between reactants and products in a chemical reaction.

What does the law of conservation of mass state?

Matter is neither created nor destroyed in a chemical reaction, meaning total mass of reactants equals total mass of products.

In stoichiometry, what do the coefficients in a balanced equation represent?

The mole ratio of the substances involved in the reaction.

Define the term 'mole'.

A unit of measurement used in chemistry to express amounts of a chemical substance, equal to 6.022 \times 10^{23} particles.

What is Avogadro's number?

6.022 \times 10^{23}

How is molar mass calculated?

By summing the atomic masses of all atoms in a chemical formula, expressed in g\,mol^{-1}.

What is a limiting reactant?

The substance that is totally consumed when the chemical reaction is complete, limiting the amount of product formed.

Define excess reactant.

The reactant that remains after a chemical reaction has reached completion.

What is theoretical yield?

The maximum amount of product that can be produced from a given amount of reactant based on stoichiometric calculations.

What is actual yield?

The amount of product actually obtained from a reaction in a laboratory setting.

How do you calculate percent yield?

\text{Percent Yield} = \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100\%

Define molar volume of a gas at STP.

The volume occupied by one mole of any gas at standard temperature and pressure, which is 22.4\,dm^3.

What are the conditions for Standard Temperature and Pressure (STP)?

A temperature of 273.15\,K and a pressure of 100\,kPa (or 1\,atm).

What is the formula for the Ideal Gas Law?

PV = nRT

In PV=nRT, what does 'R' represent?

The ideal gas constant, which is approximately 8.314\,J\,mol^{-1}\,K^{-1}.

What is molarity (M)?

A measure of concentration defined as the number of moles of solute per cubic decimeter of solution (mol\,dm^{-3}).

State the formula for calculating moles from mass.

n = \frac{m}{M} where m is mass and M is molar mass.

Define empirical formula.

The simplest whole-number ratio of atoms of each element present in a compound.

Define molecular formula.

The actual number of atoms of each element in a molecule of a compound.

What is the relationship between molecular formula and empirical formula?

\text{Molecular Formula} = n \times (\text{Empirical Formula}) where n = \frac{\text{Molar Mass}}{\text{Empirical Formula Mass}}.

What is a precipitation reaction?

A chemical reaction in which two soluble salts in aqueous solution combine to form an insoluble solid called a precipitate.

What is an exothermic reaction?

A reaction that releases energy to the surroundings, usually in the form of heat, resulting in a negative change in enthalpy (\Delta H < 0).

What is an endothermic reaction?

A reaction that absorbs energy from the surroundings, resulting in a positive change in enthalpy (\Delta H > 0).

Define titration.

A laboratory technique used to determine the concentration of a solution by reacting it with a solution of known concentration.

What is the equivalence point in a titration?

The point at which the added titrant is chemically equivalent to the analyte in the sample.