Extreme Chemistry Weaknesses

Question 1

What is the pH scale?

Answer 1

The pH scale is a measure of how acidic or basic a solution is.

Question 2

How does the pH scale measure the acidity or basicity of a solution?

Answer 2

The acidity or basicity is measured off the concentration of positive hydrogen ions in comparison to the concentration of negative hydroxyl ions. If there are more positive hydrogen ions, it is acidic. If there are more negative hydroxyl ions, it is basic.

Question 3

What is alkalinity? What does it tell us?

Answer 3

Alkalinity is the measurement of how easily a solution’s pH can change. It tells us how much buffering power a solution has to neutralize any added acids.

Question 4

What unit is alkalinity represented as? Provide an example.

Answer 4

mg/L
For example, 100mg/L of calcium carbonate.

Question 5

If a solution had an alkalinity of 100mg/L of calcium carbonate, what does this mean in terms of acid.

Answer 5

Acids added below this amount would only barely affect the pH. Once you go above that buffering space, the pH will change drastically.

Question 6

Is the alkalinity of a solution related to the acidity or basicity of a solution?

Answer 6

No. The acidity can be really low, yet the alkalinity, or vice versa, or they could both be the same. They don’t affect each other’s measurements, but alkalinity does affect how much the pH can change.

Question 7

What is the role of alkalinity?

Answer 7

To resist and neutralize the addition of acid to maintain a higher pH.

Question 8

If there are 15 dissolved hydroxyl ions and 10 dissolved hydrogen ions, is the solution acidic or basic?

Answer 8

Basic as there are more hydroxyl ions than hydrogen ions.

Question 9

If there are 109 hydroxyl ions and 203 hydrogen ions, is the solution acidic or basic?

Answer 9

Acidic as there are more hydrogen ions than hydroxyl ions.

Question 10

If a solution has a pH of 2, is it acidic or basic?

Answer 10

Acidic as the pH is lower than 7.

Question 11

If a solution has a pH of 7, is it acidic or basic?

Answer 11

None, it is neutral.

Question 12

If a solution has a pH of 11 is it acidic or basic?

Answer 12

Basic as the pH is greater than7.

Question 13

What is an alloy?

Answer 13

A mixture of a metal and other elements. This could be multiple metals or 1 metal and non-metals/metalloids.

Question 14

Is an alloy chemically bonded?

Answer 14

Yes.

Question 15

What type of bond is made in alloys that are just metals.

Answer 15

Metallic bonds

Question 16

Why are alloys useful?

Answer 16

Alloys are useful because they combine the properties of multiple metals, creating materials with enhanced characteristics. This includes improved strength and durability, resistance to rust and corrosion, and improved hardness.

Question 17

What bond do 2 metals use, ionic, covalent, or metallic?

Answer 17

Metallic bond.

Question 18

In a metallic bond, are the metal ions positively or negatively charged?

Answer 18

They are positively charged as they lose their electrons into the sea of electrons.

Question 19

Are all the valence electrons released into the sea of electrons in a metallic bond?

Answer 19

No. All valence electrons are involved in the bond, yet some remain close to their parent metal ion while the rest are in the sea of electrons.

Question 20

What is the sea of electrons and what does it mean for the metallic bond.

Answer 20

The sea of electrons is the space between the metal ions. It means that electrons are not specifically bonded to specific atoms, rather they move freely and are delocalized.

Question 21

In a metallic bond, how are the atoms held in place?

Answer 21

They are held in place by the electron sea. The positive ions are attracted to the negative electrons, keeping them all together.

Question 22

What is a metalloid.

Answer 22

An element that has properties of both a metal and non-metal.

Question 23

Where on the periodic table are metalloids found.

Answer 23

Metalloids are found on the metalloid staircase.

Question 24

What bonds do metalloids form?

Answer 24

Metalloids can form all 3 bonds.

Question 25

What happens when metalloids react with nonmetals?
a) They form metallic bonds.
b) They tend to form covalent bonds.
c) They are inert and do not form bonds.
d) They form ionic bonds only.

Answer 25

b) They tend to form covalent bonds.

Question 26

Which of these is a property of metalloids?
a) They are highly malleable and ductile.
b) They are poor conductors of electricity.
c) They are typically brittle and semi-conductive.
d) They are nonreactive with oxygen.

Answer 26

c) They are typically brittle and semi-conductive.

Question 27

Enthalpy definition

Answer 27

Enthalpy is the measure of how much heat or energy content something has.

Question 28

Entropy definition

Answer 28

Entropy is the measure of how disordered the atoms in a system are arranged.

Question 29

The amount of change in enthalpy indicates what?

Answer 29

Whether a reaction is exothermic or endothermic.

Question 30

When the enthalpy is less than 0, is it exothermic or endothermic. Hint: less heat inside the content means all the energy is outside

Answer 30

Exothermic because it has outputted all of its energy.

Question 31

When the enthalpy is more than 0, is it exothermic or endothermic? Hint: More heat within the content means energy is still contained.

Answer 31

Endothermic because it has absorbed all of the energy.

Question 32

When water freezes, the surroundings are heated up. Is this exothermic or endothermic?

Answer 32

Exothermic as the heat has left the water and entered the surroundings.

Question 33

When ammonium nitrate is dissolved in water, the solution feels cold. Is this exothermic or endothermic.

Answer 33

Since it feels cold, it has absorbed energy. This means it is endothermic.