Chem 111 Midterm

Front 1

Accuracy

Back 1

Determined by how close a measurement is to a "True" or "Accepted" value. Accuracy is measured in terms of error.

Front 2

Error

Back 2

The difference between the measures value of a quantity and the "True" or "accepted" value. Error is classified as either systematic or random.

Front 3

Systematic Error

Back 3

Is attributable to definite cause such as an instrument, malfunction, miscalculation, or erroneous technique.

Front 4

Random Error

Back 4

Characteristic of a particular device or instrument or an individual's technique.

Front 5

Precision

Back 5

Is defined as the reproducibility of results or how many decimal places you can measure with a particular instrument

Front 6

On a ruler, it is point to the 3 in centimeters. What is the marking?

Back 6

3.0 cm

Front 7

On a thermometer, it is at the long 63. How would you write that?

Back 7

63.0°C

Front 8

On a graduated cylinder, it is filled up to the line of 43. How would you write that?

Back 8

43.0 mL

Front 9

What is the formula for Density ?

Back 9

Mass ÷ Volume

Front 10

What are the units of density ?

Back 10

(g/mL)

Front 11

What is the formula for percent error ?

Back 11

Experimental - Accepted ÷ Accepted ×100

Front 12

Law of Conservation of Mass

Back 12

States that the mass of any one element at the beginning of a reaction will equal the mass of the element at the end of the reaction.

Front 13

Law of Definite Proportions

Back 13

States that a pure compound will always have the same elements combined in the same proportions by mass

Front 14

Law of Constant Composition

Back 14

Applies regardless of how the substance is made, where it is found, or how many different reactions are followed to form the compound.

Front 15

Empirical Formula

Back 15

Is the simplest whole number ratio of atoms of each element in the compound

Front 16

Molecular Formula

Back 16

Represents the actual number of each type of atoms in a compound

Front 17

Formula for calculating molecular formula

Back 17

Molecular molar mass ÷ empirical molar mass

Front 18

Stoichiometry

Back 18

The numerical relationships between chemical amounts in a balanced chemical equation

Front 19

Limiting Reactant

Back 19

Reactant that is completely consumed in a chemical reaction

Front 20

Reactant in Excess

Back 20

Any reactant that occurs in greater quantity than is required to completely react with the limiting reactant

Front 21

Theoretical Yield

Back 21

Macimum amount of product that can be produced in a chemical reaction based on the amount of limiting reactant available

Front 22

Actual yield

Back 22

The amount of product that is actually produced or recovered experimentally in a lab

Front 23

Percent yield

Back 23

The percentage of the theoretical yield thay is obtained experimentally in a lab

Front 24

Precipitate

Back 24

The solid is formed as a result of a chemical reaction

Front 25

Supernatant Liquid or Supernate

Back 25

the liquid solution that exists above the precipitate in the reaction mixture

Front 26

Filtration

Back 26

the use of filter paper to separate an insoluable solid from a liquid in a reaction mixture

Front 27

Residue

Back 27

The precipitate thay collects on the filter paper

Front 28

Filtrate

Back 28

The liquid that passes through the filter paper and the funnel

Front 29

Formula of % yield

Back 29

Mass of actual yield ÷ mass of theoretical yield × 100%

Front 30

Molarity

Back 30

A measure of amount of solute in a solution

Front 31

What is the formula for Molarity

Back 31

Mol of Solute ÷ L of solution

Front 32

Combination Reaction

Back 32

Is a reaction in which two or more reactant are combined to form a single product.

Front 33

What is the formula for a combination reaction ?

Back 33

A + B 》 AB

Front 34

Decomposition Reaction

Back 34

When a single reactant is decomposed or broken down into two or more products

Front 35

What is the formula for a decomposition reaction

Back 35

AB 》 A + B

Front 36

Single Replacement Reaction

Back 36

A substitution or displacement reaction occurs when a single free element replaces or is substituted for one of the elements in a chemical compound

Front 37

What is the formula for a single replacement reaction

Back 37

A + BC 》 AC + B

Front 38

Double Replacement Reaction

Back 38

Is a reaction in which there is an "exchange in partners"

Front 39

What is the formula for a double replacement reaction

Back 39

AB + CD 》 AD + CB

Front 40

Molecular equation

Back 40

Is the chemical equation that shows the complete neutral formulas for every compound in a reaction

2NH4Cl(aq) + Ca(OH)2(aq) 》 2NH3(g) + 2H2O(l) + CaCl2(aq)

Front 41

Complete ionic equation

Back 41

Is the chemical equation that shows all of the species as they are actually present in a solution

2NH4+ + 2Cl- + Ca+2 + 2OH- 》 2NH3 + 2H2O + Ca+2 + 2Cl-

Front 42

Net ionic

Back 42

Is an equation thay shows only the species thay change during the reaction

NH4+(aq) + OH-(aq) 》 NH3(g) + H2O(l)

Front 43

Spectator ions

Back 43

Which do not participate in the reaction and remain unchanged on both sides of a chemical equation are included in the complete ionic equation but are excluded in the net ionic equation