General Chemistry- Compounds and Stoichiometry Flashcards Preview

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Flashcards in General Chemistry- Compounds and Stoichiometry Deck (112)
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1

What are compounds?

Pure substances composed of two or more elements in a fixed proportion.

2

How can compounds be broken down?

Compounds can be broken down by chemical means

3

What do broken down compounds produce?

Compounds produce their constituent elements or other compounds.

4

How are compounds characterized?

They are characterized by describing their physical and chemical properties.

5

What is a molecule?

A combination of two or more atoms held together by covalent bonds.

6

Molecules are what to compounds?

The smallest units of compounds that display their identifying properties

7

What can molecules be composed of?

Two or more atoms of the same element
Atoms of different elements

8

Measurements of compounds is usually done with what?

Moles or grams
Using molar mass to interconvert between the units

9

What does not form a true molecule? Why?

Ionic compounds do not form true molecules because of the way in which the oppositely charged ions arrange themseves in the solid state

10

What is a formula unit?

The empirical formula of a compound

11

Why is the term formula weight used?

Because no molecule actually exists, molecular weight becomes meaningless, so formula weight is used instead.

12

What is molecular weight?

The sum of the atomic weights of all the atoms in a molecule

13

What units are used for molecular weight?

Atomic mass units (AMU) per molecule

14

How is the formula weight found?

Adding up the atomic weights of the constituent ions according to its empirical formula.

15

What units are used for formula weight?

Atomic Mass Units (AMU) per molecule

16

One mole of a compound has a mass in grams equal to what?

1 mole of a compound has a mass in grams equal to the molecular or formula weight of the compound in AMU

17

What is molar mass?

The mass of one mole of a compound

18

What units are used to describe molar mass?

(g/mol)

19

What is the equation for determining the number of moles of a sample substance?

Moles= Mass of sample (g)/Molar mass (g/mol)

20

Which equation is usually used in stoichiometry and titration problems?

The formula for determining the number of moles of a sample

21

What is the concept of equivalents?

How many moles of the thing we are interested in (protons, hydroxide ions, electrons, ions...) will one mole of a given compound produce

22

How many equivalents will sodium donate?

one mole of electrons (one equivalent)

23

How many equivalents will magnesium donate?

Two moles of electrons (two equivalents)

24

What is the gram equivalent weight?

The amount of a compound, measured in grams, that produces one equivalent of the particle of interest.

25

What equation is used to calculate the gram equivalent weight?

Gram equivalent weight= Molar mass/n

26

What do the words/letters represent in the equation for gram equivalent weight?

Gram equivalent weight= Molar mass/n
n: the # of particles of interest produced or consumed per molecule of the compound in the reaction.

27

What is the simplified version for explaining the equivalent weight?

The mass that provides one mole of the particle of interest.

28

What equation is used to determine the number of equivalents that are present, if the amount of a compound in a reaction is known?

Equivalents= Mass of compound (g)/ (Grams equivalent weight (g))

29

What is normality?

(N) is a measure of concentration, given in the units equivalents/L

30

On the MCAT, what is normality normally used for?

Hydrogen ion concentration.