Mass Relationships in Chemical Reactions

These flashcards cover key concepts related to mass relationships in chemical reactions, including atomic mass, Avogadro's number, and percent composition.

What is the average atomic mass of carbon based on its isotopes?

12.01 amu, calculated as (0.9890)(12 amu) + (0.0110)(13 amu).

What is Avogadro's number?

6.022 x 10^23, the number of atoms in exactly 12 grams of carbon-12.

How is molar mass calculated?

Molar mass (M) = mass (g) / moles (mol).

What is the definition of molecular mass?

The sum of the atomic masses (in amu) in a molecule.

What is the formula to calculate the percent composition of an element in a compound?

% composition = (n x molar mass of element / molar mass of compound) x 100%.

Which substance has the highest nitrogen percentage? (NH2)2CO, NH4NO3, HNC(NH2)2, NH3?

According to the calculations, ammonia (NH3) has the highest nitrogen percentage at 82.4%.

How do you determine the empirical formula from percent composition?

Convert mass percentages to moles, divide by the smallest number of moles, and use ratios to find whole numbers.

Define limiting reagent.

The reactant that is used up first in a reaction, determining the amount of product formed.

What is theoretical yield?

The maximum amount of product that can be produced based on the limiting reagent in a chemical reaction.

What is the formula for calculating percent yield?

% Yield = (Actual Yield / Theoretical Yield) x 100%.