Chapter 6 Flashcards
The process of breaking the chemical bonds which hold the different atoms together in a compound is called __________.
decomposition
We call the mass ratio for each element present in a compound the _____ ________.
percent composition
A ________ ______ is the sum of the atomic masses of all the atoms represented in the chemical formula of a substance.
formula mass
The term _____ is a Greek term used to describe a heap or pile.
mole
The term _______ is the dimunitive form of a mole meaning the smallest portion of the heap or pile.
molecule
Chemists now use the value of a ____ like a baker uses the value of a dozen.
mole
Avogadro’s number of particles for any pure substance is equal to it’s ___ ____ ___ ____ rather than amu.
formula mass in grams
Since Avogadro’s number of particles for any substance is numerically equal to the formula mass in grams, the formula mass is often called the ___ ___ of a substance.
molar mass
____ ____ = the mass of 1 mole of a given substance.
molar mass
The molar mass of an element is numerically equal to the _____ _____ of that element.
atomic mass
The molar mass is used as a ______ ______ to calculate the number of moles found in a given gram mass of a substance or vice versa.
conversion factor
The ____ of ____ of _____ simply states that when making a chemical substance with exactly the right amount of ingredients, the resulting total product mass is exactly the same as the total starting mass. In other words, during a normal chemical reaction, mass cannot be created nor destroyed.
The law of conservation of mass
The _____ _____ is simply a description of the overall chemical reaction using the molecular or ionic formulas to represent the starting material(s) and the product(s).
chemical equation
The ingredients, which we call _____, are listed on the left side of the equation.
reactants
The final results or ______ of the reaction are listed on the right side of the equation.
products
Reactants are also called _____ _____.
chemical reagents
The ______ is a whole number used to describe the exact number of molecules or atoms that are needed to participate in an exact reaction.
coefficient
What is the subscript for gas?
(g)
What is the subscript for liquid?
(l)
What is the subscript for solid?
(s)
What is the subscript for aqueous solution (dissolved in water)?
(aq)
Before a chemical equation is actually useful, it must be _______.
balanced
When a chemical equation is balanced the ____ and ____ of atoms found on the left side will exactly match the number and types of atoms found on the right side.
number and types
Only the _______ can be changed to balance an equation.
coefficient
The word, ________ is a German term that means “element balance”.
stoichiometry
______ ______ are done on paper assuming that the reaction will go to completion with no loss of either products or reactants.
Theoretical calculations
The amount of product in theoretical calculations are called _____ _____.
theoretical yield
After performing the chemical reaction and isolating the product, the actual weighed amount of product is called the _____ ______.
actual yield
How close a chemist comes to isolating the theoretical amount of product from an actual experiment is called the ______ ______.
percent yield
What is the calculation to find the percent yield?
actual experimental mass / calculated theoretical mass x 100
The problem with knowing the number of atoms or molecules in a given sample of a pure substance is______________________________________.
the particles that make up the substance are too small and way too numerous to count.
Elements in a given compound are always found in definite _______ or _______.
ratio or proportion
What is the ratio of C atoms to O atoms in carbon dioxide?
1 carbon atom for every 2 oxygen atoms; 1:2 ratio
How does one mix atoms in a proper ratio without counting them?
by weighing them
Water has a fixed ratio by ____ of O atoms and H atoms.
mass
TRUE or FALSE:
Pure water in Argentina has the same mass ratio of H and O as water in the US.
true
TRUE or FALSE:
It is possible that 2 different compounds happen to have the same percent composition of elements.
true
If an oxygen atom weighs 16.00amu and a hydrogen atom weighs 1.01amu, what is the total mass of a water molecule in amu?
18.02amu (sum of all atoms)
What 2 pieces of information or data are required to count particles by weighing?
the average mass of each item present and the total mass of all items
The molar mass and the ______ mass are numerically the same value.
formula
If the units for the formula mass are amu, what are the units of the molar mass?
grams/mole
TRUE or FALSE:
The molar mass is used to calculate the actual number of particles in a certain mass.
false - this would give the moles of particle
What conversion factor is needed to convert from grams of a substance to moles of the substance?
molar mass
If you are given grams of a substance and are asked to determine the number of atoms or molecules of that substance, what value must be calculated first?
moles
TRUE or FALSE:
During a normal chemical reaction the mass of the products and any left over material always equal the mass of the starting materials.
true
What is drawn between the reactants and products?
an arrow
The plus sign in a chemical equation is equivalent to the word, ______.
and
Products of a chemical reaction are listed on the _____ side of the equation.
right
The coefficient is used to show the ____ ____ of reactants or product molecules required for or produced by the reaction.
actual number
TRUE or FALSE: If sulfur (S) is found in one of the product molecules it must also be present in one of the reactants.
true
When balancing a chemical equation, only the ______ values can be altered.
coefficient
Changing the subscripts of the formulas will change the ________ of the substance.
identity
TRUE or FALSE: If carbon (C) is found in all of the reactants, it must also be present in all of the products.
false
Balancing a chemical reaction gives us the correct ______ ______ of reactants and products.
proper ratios
TRUE or FALSE:
The actual yield can be calculated using stoichiometry and a balanced chemical equation
false
