Introduction to Water - Online Tutor, Practice Problems & Exam Prep

Water, a polar molecule with the formula H₂O, exhibits unique properties due to hydrogen bonding. These emergent properties include cohesion, adhesion, low density of ice, high specific heat, and its role as a universal solvent. Understanding these characteristics is essential for grasping water's significance in biological systems and its ability to support life on Earth.

Introduction to Water

In this video, we're going to begin our introduction to water. And so, of course, as you guys already know, water is a very small polar molecule with 2 hydrogen atoms and one oxygen atom. And so, of course, its chemical formula is going to be H₂O, one oxygen and 2 hydrogens. Now recall when we first introduced polar covalent bonds in our previous lesson videos, we showed you that water is an example of a molecule with polar covalent bonds, and this is what makes water a polar molecule. Now because water is a polar molecule, it means that it's going to have partial negative and partial positive charges.

And so recall that the oxygen atom of every single water molecule is going to have a partial negative charge, whereas the hydrogen atoms on every water molecule are going to have partial positive charges. And so the partial negative charge and the partial positive charges on water molecules is what allows for water molecules to form hydrogen bonds. And so hydrogen bonds we know will form between different water molecules. And so if we take a look at the right hand side of our image over here, notice that we're showing you water's hydrogen bonding. And so you can see that the hydrogen bonds are highlighted here in yellow, and the hydrogen bonds are forming between different water molecules.

And so this is really, really important for many different types of properties that water has and we'll get to talk more about these properties that water has in our next lesson video. So I'll see you guys there.

Individual water molecules bind to each other through:

• A. Covalent bonds.
• B. Ionic bonds.
• C. Hydrogen bonds.
• D. Hydrophobic bonds.

Emergent Properties of Water

In this video, we're going to briefly introduce some of the emergent properties of water. And so really, it's water's hydrogen bonding that gives rise to 4 emergent properties and really these 4 emergent properties of water are essential to maintain life on Earth. Now moving forward in our course, we're going to talk about each of these 4 emergent properties of water in their own separate videos. But notice down below we're showing you a table of the 4 emergent properties of water. And so the first is water's ability, to perform cohesion, adhesion, and to have surface tension.

The second emergent property of water is water's low density when it's in the solid ice form compared to the liquid water form. The third emergent property of water is its high specific heat and heat of vaporization. And then the fourth emergent property of water is that it is used as a universal solvent in mixed solutions. And so once again, we're going to talk about each of these 4 emergent properties of water in their own separate videos moving forward in our course. So I'll see you all in our next video.

Introduction to Water Example 1

Alright. So here we have an example problem that says, which of the following is not an emergent property of water? And we've got these four potential answer options down below. Now, once again, moving forward in our course, we're going to talk about each of the properties of water in their own separate videos. But from our last lesson video, we should be able to determine what the correct answer is here.

And so we know from our last lesson video that one of the properties of water is that it has adhesive and cohesive properties. It can perform cohesion and adhesion. And so because this is definitely something that water is able to do, we can eliminate answer option a since we're looking for options that are not an emergent property of water. And we can also eliminate answer option d since we also know that this is something that water is capable of doing. It is going to be used as the universal solvent in chemical reactions.

And so once again, we can eliminate answer option d. So now we're between either option b or option c. And what you might realize is that option c says high density of ice compared to liquid water. Whereas in our last lesson video, we said that there was low density of ice compared to liquid water. And so the high here is actually something that is false because it says high.

And so because this is false, this is not an emergent property of water. This is the one that we're looking for. And so option b must be something that is a property of water, and it says moderation of temperature, and this is something that water is capable of doing. And once again, we'll talk more about this idea later in our course. But for now, we can go ahead and indicate that option c here is the one that is not an emergent property of water, and that concludes this example.

So I'll see you all in our next video.

The emergent properties of water (cohesion, high heat capacity, good solvent) come from the fact that water is ______ and ______ hydrogen bond.

• A. Polar, can.
• B. Polar, cannot.
• C. Non-polar, can.
• D. Non-polar, cannot.

Here’s what students ask on this topic:

What makes water a polar molecule?

Water is a polar molecule due to the presence of polar covalent bonds between the oxygen and hydrogen atoms. In a water molecule (H₂O), the oxygen atom is more electronegative than the hydrogen atoms, causing it to attract the shared electrons more strongly. This results in a partial negative charge (δ-) on the oxygen atom and partial positive charges (δ+) on the hydrogen atoms. The unequal distribution of charges creates a dipole moment, making water a polar molecule. This polarity allows water molecules to form hydrogen bonds with each other, contributing to its unique properties.

What are the four emergent properties of water that are essential for life?

The four emergent properties of water essential for life are: 1) Cohesion, adhesion, and surface tension: These properties allow water molecules to stick to each other and to other surfaces, facilitating processes like capillary action in plants. 2) Low density of ice: Ice is less dense than liquid water, allowing it to float and insulate aquatic life in cold environments. 3) High specific heat and heat of vaporization: Water can absorb and release large amounts of heat with minimal temperature change, helping to regulate climate and body temperature. 4) Universal solvent: Water's polarity allows it to dissolve a wide range of substances, making it crucial for biochemical reactions and nutrient transport.

How do hydrogen bonds contribute to water's unique properties?

Hydrogen bonds are weak interactions that form between the partial positive charge of hydrogen atoms in one water molecule and the partial negative charge of oxygen atoms in another. These bonds are responsible for many of water's unique properties. For example, hydrogen bonding leads to high cohesion and surface tension, allowing water to form droplets and enabling capillary action. It also contributes to water's high specific heat, meaning it can absorb significant heat without a large temperature increase, which helps stabilize climates and organisms' internal temperatures. Additionally, hydrogen bonds cause ice to be less dense than liquid water, allowing it to float and insulate aquatic life.

Why is water considered a universal solvent?

Water is considered a universal solvent due to its polarity and ability to form hydrogen bonds. The partial positive and negative charges on water molecules allow them to interact with and dissolve a wide variety of substances. When ionic compounds dissolve in water, the positive and negative ions are surrounded by water molecules, preventing them from recombining. Similarly, water can dissolve many polar molecules by forming hydrogen bonds with them. This property is crucial for biological systems, as it enables the transport of nutrients, waste products, and other molecules within organisms and across cell membranes.

What is the significance of water's high specific heat in biological systems?

Water's high specific heat is significant in biological systems because it allows water to absorb and release large amounts of heat with minimal temperature change. This property helps stabilize the internal temperature of organisms, providing a consistent environment for biochemical reactions. It also plays a crucial role in regulating Earth's climate by moderating temperature fluctuations. For example, large bodies of water like oceans and lakes can absorb heat during the day and release it at night, reducing temperature extremes. This thermal stability is essential for maintaining life and supporting diverse ecosystems.