Bio- water, hydrogen bonds, etc.

Cohesion

The tendency for the same kind of molecules to stick together. (ex. water + water)

Adhesion

Cling of one substance, to a different one. (ex. water + glass tube)

Surface Tension

A measure of how difficult it is to stretch or break a surface of liquid

Hydrogen Bonds

A weak attraction between water and a highly electronegative atom (ex. Oxygen, Nitrogon, Fluorine)

What do Hydrogen Bonds do

• Creates stronger surface tension

• Regulate temp. of of water to store more heat (stores more heat but takes more energy for temp to rise)

Solution

A mixture of 1+ solutes dissolved in a solvent

Solute

The substance that is being dissolved

Solvent

The dissolving agent (water = universal solvent)

Accuracy

Closeness of a measurement to the true value

Pecision

How close of the measurements of the same item are to each other

What is water's compund

H2O

Why is water unique?

Because it has a slight polarness

Hydrophobic

Repels water causing it to turn into beads (ex. oil because it repels water)

Hydrophilic

Causes water to spread across its surface/absorbs water

What is the bond within water molecules and why?

Polar covalent because Oxygen is slightly - and Hydrogen is slightly +

What are the bonds between water molecules and why?

Hydrogen bonds --> because of the uneven sharing of electrons in a polar covalent bond

How long to hydrogen bonds last?

A trillionth of a second

How many molecules do hydrogen bonds form between?

2 molecules

How does electronegativity lead to polar covalent bonds within a molecule?

Electronegativity forms polar covalent bonds when electrons are shared unequally because they have different electronegativity.

How does electronegativity lead to H bonds between molecules?

Because the hydrogen atom covalently bonded to a highly electronegative atom has a slightly negative charge while the electronegative atom has a slighlt positive charge which is attracted to atoms of the opposite charge (ex. O- and H+)

Which numbers are certain on reading a scale?

The numbers that are told based off of marking on the ruler/graduated cylinder

How many guesses do you get when guessing numbers on a scale?

To one place value

How do H bonds differ from chemical bonds?

Because H bonds are very weak while chemical bonds are very strong. H bonds are also based off of attraction of compounds while chemical bonds are based off of the sharing/transferring of electrons.

What is electronegativity?

A measure of how strongly an atom attracts electrons towards itself within a chemical bond

Why is water considered the universal solvent?

Because it can dissolve more types of substances than any other liquid.

What is the pH scale and what does it measure from? What number is neutral?

The measure of how acidic or basic a substance is and it's on a scale of 0-14. Neutral is at 7 (ex. pure water and some soaps)

What is an acid in the pH scale?

• compounds that donate H+ ions into a solution

• contains a higher solution of H+ than OH-

• range of 0<7

• tastes sour (ex. lemons) and can burn skins/eyes

• ex. HCI in stomach (dissociates H+ and Cl- leading to a higher concentration of H+

What is a base in the pH scale?

• compound that remove H+ from a solution by accepting H+ ions

• contains higher concentration of OH- than H+

• pH range of 7<14 (aka alkaline)

• tastes bitter (ex. soap) + feels slippery and slimy

• ex. NaOH which dissociates Na+ and OH-

• the OH- combines w/ the H+ in the solution forming H2O molecules

What are the pH of cells + blood plasma?

Cells = close to 7

Blood plasma is approx 7.4

Why does pH matter to living things?

It is critical for biochemical reactions w/ protein structure and enzyme function

It also serves as a buffer in the body to help regulate pH by accepting or donating H+ ions

Scientific definition for Acids

A proton (H+) donor

Scientific definition for Bases

A proton (H+) acceptor

What's cabbage juice used for?

It's an indicator of whether a solution is a base, acid, or neutral

What colors does cabbage juice turn and why?

Basic = green + blue

Acidic = pink + red

Neutral = purple