name: jadarrian crump 5\ week
properties of water and ph
1. write the chemical equation for water, and draw a stick model of a water molecule. show polarity by label positive and negatively charged regions of the molecule.
3. what kind of bond holds the hydrogen to the oxygen in one water molecule?
4. what kind of bonds can hold two separate water molecules together?
5. what is a polar molecule?
6. the polarity of water allows it to ____________ most substances. because of this it is referred to as the ____________________.
7. water molecules stick to other water molecules. this property is called ______________.
8. water molecules stick to other water molecules. this property is called ______________.
9. why does ice float on water?
10. why is it important that water resists temperature changes?
critical reading: ph
when some substances dissolve in water they break up into ions. a compound that releases a hydrogen ion (a proton) when it dissolves in water is an acid. bases are compounds that remove, or accept, hydrogen ions. a solution’s acidity, or its hydrogen ion concentration, is measured on the ph scale. an acid has a low ph (ph below 7) and a high hydrogen ion concentration. a base has a high ph (ph above 7) and a low hydrogen ion concentration. organisms must maintain a stable ph. even a small change in ph can disrupt many biological processes.
11. describe what the ph of a substance is measuring.
12. draw the ph scale and label acid, neutral, and base.
13. what has more hydrogen ions, acids or bases?

Question

Accepted Answer

### Question 3
# Brief Explanations:
In a water molecule ($H_2O$), the bond between hydrogen (H) and oxygen (O) is a covalent bond. Specifically, it is a polar covalent bond because oxygen is more electronegative than hydrogen, causing a partial charge separation, but the bond itself involves sharing of electrons between H and O.
# Answer:
The bond holding Hydrogen to Oxygen in one water molecule is a **polar covalent bond** (or simply "covalent bond" for a more basic answer).

### Question 4
# Brief Explanations:
Two separate water molecules are held together by hydrogen bonds. The partially positive hydrogen of one water molecule is attracted to the partially negative oxygen of another water molecule, forming this intermolecular force.
# Answer:
The bonds that hold two separate water molecules together are **hydrogen bonds**.

### Question 5
# Brief Explanations:
A polar molecule is a molecule where there is an unequal distribution of electron density, resulting in a molecule with a partial positive charge on one end and a partial negative charge on the other end. This occurs due to differences in electronegativity between the atoms in the molecule, leading to a dipole moment (a separation of charge). For example, water ($H_2O$) is polar because oxygen is more electronegative than hydrogen, so the oxygen end is partially negative and the hydrogen ends are partially positive.
# Answer:
A polar molecule is a molecule with a **partial positive charge on one region and a partial negative charge on another region** (due to unequal sharing of electrons/electronegativity differences), resulting in a dipole moment.

### Question 6
# Brief Explanations:
The polarity of water (due to its polar covalent bonds and bent molecular shape) allows it to dissolve most substances, especially polar or ionic substances. Because of its ability to dissolve many substances, water is referred to as the "universal solvent".
# Answer:
The polarity of water allows it to $\boldsymbol{	ext{dissolve}}$ most substances. Because of this it is referred to as the $\boldsymbol{	ext{universal solvent}}$.

### Question 7 (and Question 8, which appears to be a repeat of Question 7)
# Brief Explanations:
The property where water molecules stick to other water molecules is called cohesion. This is due to hydrogen bonding between the partially positive hydrogens of one water molecule and the partially negative oxygens of adjacent water molecules.
# Answer:
Water molecules sticking to other water molecules is called $\boldsymbol{	ext{cohesion}}$. (Note: Question 8 is a repeat, so the answer is the same as Question 7.)

### Question 9
# Brief Explanations:
Ice floats on water because the density of ice is less than the density of liquid water. When water freezes, the water molecules form a crystalline structure (hexagonal lattice) due to hydrogen bonding, which spaces the molecules further apart than in the liquid state. This increased spacing results in a lower density for ice compared to liquid water, so ice is less dense and floats.
# Answer:
Ice floats on water because **ice is less dense than liquid water**. When water freezes, its molecules form a structured lattice (due to hydrogen bonding) that increases the space between molecules, reducing ice’s density.

### Question 10
# Brief Explanations:
Water’s ability to resist temperature changes (high specific heat capacity) is important because it helps regulate temperatures in environments (like oceans, lakes, and organisms). For example, in ecosystems, large bodies of water moderate climate by absorbing heat in warm weather and releasing it in cold weather. In organisms, water’s temperature stability helps maintain a constant internal temperature (homeostasis), as biochemical reactions are sensitive to temperature changes.
# Answer:
It is important that water resists temperature changes because it helps **regulate temperatures in environments (e.g., climate moderation in ecosystems)** and **maintain stable internal temperatures in organisms (homeostasis)**, as biological processes are sensitive to temperature fluctuations.

### Question 11
# Brief Explanations:
From the provided reading, the pH of a substance measures the solution’s acidity, specifically the hydrogen ion ($H^+$) concentration. A low pH (below 7) means a high hydrogen ion concentration (acidic), and a high pH (above 7) means a low hydrogen ion concentration (basic).
# Answer:
The pH of a substance measures the **acidity (or hydrogen ion concentration)** of a solution. A low pH indicates a high $H^+$ concentration (acidic), and a high pH indicates a low $H^+$ concentration (basic).

### Question 12
# Brief Explanations:
The pH scale ranges from 0 to 14. A pH of 7 is neutral (e.g., pure water). Values below 7 (0–6.9) are acidic (higher $H^+$ concentration), and values above 7 (7.1–14) are basic (lower $H^+$ concentration, higher $OH^-$ concentration). To draw it: create a horizontal line, label the left end "0 (most acidic)", the middle "7 (neutral)", and the right end "14 (most basic)". Mark "acid" below the 0–6.9 range, "neutral" at 7, and "base" below the 7.1–14 range.
# Answer:
To draw the pH scale:
- Draw a horizontal line (or vertical scale) with values from 0 to 14.
- Label "0" on the left (most acidic), "7" in the middle (neutral), and "14" on the right (most basic).
- Label the region **0–6.9** as "Acid", **7** as "Neutral", and **7.1–14** as "Base".

### Question 13
# Brief Explanations:
From the reading: "An acid has a low pH (pH below 7) and a high hydrogen ion concentration. A base has a high pH (pH above 7) and a low hydrogen ion concentration." So acids have more hydrogen ions than bases.
# Answer:
**Acids** have more hydrogen ions than bases.

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

Question 3

Answer:

Question 4