Lecture 1 Flashcards
(22 cards)
What is stoichiometry concerned with?
Relative amounts of reactants and products in a chemical reaction
What does a chemical equation tell us?
The ratio in which reactants react to give products
True or False: Chemical equations must be balanced.
True
What is the mole (mol)?
The SI unit of the amount of substance
How is the mole defined?
As the amount of substance that contains the same number of specified entities as there are atoms in 12g of C12
How many atoms are there in 1 mole of a substance?
6.022 x 10^23 atoms
What is molar mass (M)?
The mass of 1 mole of a specified entity
Fill in the blank: Molar mass is defined in terms of mass (m) and amount of substance (n) as M = m/_____.
n
What are the units of molar mass?
gmol-1
What do balanced chemical equations provide?
Mole relationships between all reactants and products
What is a limiting reactant?
The reactant that runs out first in a reaction
What is the other reactant called when one reactant is limiting?
Excess reactant
In the reaction 2H2(g) + O2 → 2H2O(l), what happens when one reactant runs out?
The reaction stops
How do you determine the amount of product produced in a reaction?
From the amount of the limiting reactant and the mole ratios
Fill in the blank: The composition of a solution is defined in terms of its concentration: the amount of solute per volume of _____.
solvent
What is the formula for concentration (c)?
c = n/V
How do you convert grams into moles?
Use the molar mass from the table
True or False: When converting masses into moles, you should multiply by the big number in front.
False
How do you calculate remaining reactants after a reaction?
By calculating the amounts of both reactants and their conversions to products
In the example with 5g of H2 and 21g of O2, which reactant is in excess?
H2
What is the formula used to calculate remaining mass of a reactant?
M = M x n
What does stoichiometry allow us to do in chemical reactions?
Weigh bulk quantities of reactants and products
