Chpt. 11, The Mole

Question 1

mole

Answer 1

6.02 * 10^23; just as a pair is 2, and a dozen is 12, a mole is this value (6.02 * 10^23)

Question 2

the purpose of moles

Answer 2

to express large quantities more easily; it comes in handy especially when dealing with tons of atoms or molecules

Question 3

molar mass

Answer 3

the mass of one mole of a given compound or element

Question 4

how to find the molar mass of a compound

Answer 4

add up the molar masses of all the atoms of that compound

Question 5

converting moles to grams

Answer 5

Once you know the number of moles that something is, it is often important to convert that thing into grams because grams are the easiest way to measure a substance. Moles and be converted to grams, and grams to moles, by following the following rules:

1. Make your t-chart, and do the multiplication normally.
2. Every time you have a mole unit, put a “1” in front of it.
3. Every time you have atoms or molecules, but “6.02 * 10^23” in front of it.
4. Every time you have grams, put molar mass in front of it.
5. Every time you write in the upper left hand corner, disregard the other rules and write exactly what you have.

Question 6

percent composition definition

Answer 6

the percent composition of something is the amount of a given element that is in a substance is that substance’s percent composition

Question 7

percent composition equation

Answer 7

(mass of the element/compound in the substance, expressed in grams) / (mass of the substance overall, derived from molar mass and expressed in grams)

Question 8

hydrate

Answer 8

a compound that has water molecules loosely attached to it (not bonded though); hydrates can be dehydrated (their water is removed) by a variety of methods, such as burning the hydrate, for example

Question 9

anhydrate

Answer 9

a compound that has the potential to become a hydrate if water is added to it (in other words, water can attach to it, but there is not water attached to it presently)

Question 10

indicators of a hydrate

Answer 10

the following properties are merely indicators, and are not always true:

1. they have lower apparent MP and BP
2. they undergo a color change when they contact water