Chem Midterm

Front 1

Explain the difference between an element and a compound using examples.

Back 1

An element is a pure substance containing only one type atom ex: gold

An compound is a pure substance made up of different types of atoms that are bonded together ex: NaCl

Front 2

How to find density?

Back 2

Density = mass/ volume

Front 3

Explain the difference between chemical and physical properties using examples.

Back 3

Physical Properties are properties of a substance that can be observed without changing the chemical composition ex. Color

Chemical properties are a property of a substance that can ONLY be observed durring a chemical reaction ex. Bubbling

Front 4

Explain the difference between intensive and extensive using examples.

Back 4

Intensive property- a property of a substance that is NOT dependent upon sample size ex. Color

Extensive property- a property of a substance that is dependent upon sample size ex. Volume

Front 5

Explain how to use the periodic table to determine if a substance is a metal, non metal, or metalloid.

Back 5

You can use the line that separates the metals, non metals, and metalloids, an element that is touching on 2 sides are metalloids, elements to the left of the line are metals and elements to the right of the line are non metals.

Front 6

Fill in the chart

Back 6

Hyphen notation : potassium - 42

Protons : 19

Neutrons : 23

Electrons : 19

Electron Configuration : 2, 8, 8, 1

Hint 6

Front 7

Fill in the chart

Back 7

Nuclear symbol : 36 / 17 Cl

Protons : 17

Neutrons : 19

Electrons : 17

Electron Configuration : 2, 8, 7

Hint 7

Front 8

Fill in the chart

Back 8

Nuclear symbol : 36 / 16

Hyphen notation : sulfur - 36

Electrons : 16

Electron Configuration : 2, 6

Hint 8

Front 9

Fill in the chart

Back 9

Nuclear symbol : 17 / 8 O

Hyphen notation : oxygen - 17

Protons : 8

Electron configuration : 2, 6

Hint 9

Front 10

Give 2 reasons why atoms cannot be counted.

Back 10

1) Atoms are VERY small so it is very hard to count them

2) There are a ton of atoms, so many it is impossible to count them all

Front 11

Explain the rules for determining the number of sig figs in a multiplication calculation. Give an example as part of the explanation.

Back 11

Round the answer to the same number of significant figures as the price of data with the LEAST amount of sig figs. See picture for example.

Front 12

When are zeros significant in a number? Use example as part of your explanation.

Back 12

♡Zeros between significant digits ex: 302 or 102,307

♡Zeros at the end of a number after a decimal ex: 2.60 = 3 SF or 0.0020310 = 5 SF

Front 13

Write a procedure for determining the saturation level of a solution. Include an explanation of how to interpret the data that could be collected from the procedure.

Back 13

When a solute is added to a solvent at a specific temperature if the solute "dissappears" it is UNSATURATED. If the solute sinks to the bottom in a "clump" it is SATURATED. If the solution turns to a solid it is SUPERSATURATED.

Front 14

When naming acids -ic goes to what?

Back 14

-ous

Front 15

When are zeros NOT significant in a number? Use example as part of your explanation.

Back 15

◇At the beginning of a number ex. 0.0372 = 3 SF

◇At the end of a number before a decimal ex. 103,200 = 4 SF

Front 16

Stoichiometry

Back 16

The study of mass and quantity relationships in a chemical reaction

Front 17

Mole ratio

Back 17

A fraction created from the balancing numbers of a reaction to compare the quantities of each substance

Front 18

% yeild definition and equation

Back 18

A measure of the efficiency of a reaction

% yeild = actual / theoretical X 100

Front 19

Limiting reactant

Back 19

The chemical that runs out first causing the reaction to stop.

Front 20

Actual yeild

Back 20

The amount found in the lab.

Front 21

Theoretical yeild

Back 21

The amount found using stoichiometry (it is the limiting reactant)

Front 22

Why do chemists need stoichiometry?

Back 22

To calculate how much of a chemical is produced when a certain amount of another chemical is used.

Front 23

Why is it necessary to balance a reaction before doing stoichiometry?

Back 23

So that you know how many moles of each chemical are in the reaction so you can compare the quantities of each substance.

Front 24

Double displacement general form

Back 24

AX + By ➡ AY + BX

Front 25

Single Displacement general form

Back 25

A + Bx ➡ Ax + B

Front 26

Combustion general form

Back 26

A + O2 ➡ AO2

Front 27

Synthesis general form

Back 27

A + B ➡ AB

Front 28

Decomposition general form

Back 28

AB ➡ A + B

Front 29

Dissociation general form

Back 29

AB (s) ➡(H2O) A (aq) + B (aq)

Front 30

What are spectator ions and why are they not included in net ionic equations?

Back 30

They are ions in a reaction that do not react so they are not included in net ionic equations.

Front 31

Titration

Back 31

The process of finding the concentration of a solution by using a second solution of unknown concentration

Front 32

Titrant

Back 32

The solution of KNOWN concentration

Front 33

Titrate

Back 33

The solution of UNKNOWN concentration

Front 34

pH

Back 34

Shows how acidic or basic a solution is

Front 35

Indicator

Back 35

Changes color to show the pH of a solution

Front 36

Equivalence point

Back 36

Point when a solution is stoichiometrally equal and the indicator changes color

Front 37

List three things you need to do as part of the process to clean a buret.

Back 37

1) make sure the valve is closed and pour 10-15 ml of the intended solution into the buret

2) swish the solution through the entire buret

3) empty through the valve in order to clean the valve. Repeat the process 3 times

Front 38

Write neutralization reactions for the following:

Hydrochloric acid and sodium hydroxide

Back 38

HCl + NaOH ➡ H2O + NaCl

Front 39

Write neutralization reactions for the following:

Carbonic acid and lithium hydroxide

Back 39

HCO3 + H2Li ➡ H2O + LiCO3

Front 40

Write the procedure for doing a titration.

Back 40

1) clean each buret

2) fill each with the intended solution

3) remove any air bubbles

4) record initial volume

5) put 20 - 25 ml of acid in the beaker

6) put 3 drops of indicator in the beaker

7) while consistently swirling the acid and indicator add base until it remains pink for 30 seconds

8) record final volume

9) repeat for 3 trials

Front 41

Molarity definition and equation

Back 41

The number of moles of solute per liter

M = moles solute / liters of solution = moles / l

Front 42

Solution

Back 42

Stable homogenous mixture of 2 or more substances ex. Kool-aid and water

Front 43

Solute

Back 43

Substance that gets dissolved ex. Hit cocoa mix

Front 44

Solvent

Back 44

Substance that causes the solute to dissolves ex. Water when cocoa is added

Front 45

1 mole = what

Back 45

1 mole = 6.02 × 10 ^23 = atomic mass of element

Front 46

Stoichiometry general form

Back 46

Front 47

Process for writing a chemical formula

Back 47

1) determine the symbol and charge for the first word in the name using the periodic table or the charge table

2) determine the symbol and charge for the second word in the name

3) add subscripts so the positives and negatives are equal to one another (so charges cancel)

4) polyatomic ions that need a subscript should be in parenthesis

Front 48

Write a formula for chromium sulfide

Back 48

Cr2S3

Work:

Cr+3 S-2

Cr+3 S-2

S-2