Click the following link for a student study guide to the Chemistry and Properties of Water

If you’ve already watched the video, Click here, or scroll down below the video to start interacting.

 

Introduction

In the previous tutorial, we looked at the chemistry of water. We saw how water’s polar structure allows water molecules to form hydrogen bonds with other water molecules. In this tutorial, we’ll do a virtual lab that let’s us look at water’s unique properties: properties that result from hydrogen bonding.

1. A (virtual) lab comparing water and alcohol: What you’ll need

To get a sense for the properties of water, we’re going to do a virtual lab comparing water to alcohol. Since real science is always preferable to virtual science, I want to encourage you to get the supplies for this lab, and to independently try the activities.

Here’s what you’ll need:

  1. Tap water
  2. isopropyl alchol, walgreens, 500A small bottle of Isopropyl alcohol. This kind of alcohol is available at almost any supermarket or pharmacy. 90% is the best concentration for this lab.
    1. SAFETY NOTE: isopropyl alcohol is poisonous. Don’t drink it.
    2. Also, if you can’t get isopropyl alcohol, but other types of alcohol are available (such as ethyl alcohol), the lab should work perfectly well.
  3. Two eyedroppers or plastic pipettes. If you’re using pipettes, label them, and put one in the water, and the other in the alcohol. If you’re using droppers, fill one with water, and one with alcohol.
  4. A few small beakers, glasses, or cup.
  5. Two small paper clips
  6. Two pennies (or two small squares of wax paper if you can’t get a penny)
  7. Two teaspoons to do some stirring
  8. Table salt (about two teaspoons).

2. Background: Comparing Water and Isopropyl Alcohol

Based on our last tutorial, you already know a lot about water. Here’s a quick review of water’s key properties.

  1. Water is a polar molecule.
  2. The oxygen side of the molecule has a partially negative charge (?)
  3. The hydrogens, on the other side, have a partially positive charge(?+).
  4. As a result, water molecules form hydrogen bonds, interacting as shown below.
08_water, structural, with delta charges 14-hydrogen bonds in water
Water: structural formula Water molecules forming hydrogen bonds(original source: “3D model hydrogen bonds in water” by Qwerter at Czech wikipedia, (slightly modified))

Here’s isopropyl alcohol.

17_better isopropyl alcohol

640px-Propan-2-ol-3D-balls
Source: “Propan-2-ol-3D-balls” by Jynto  via Wikimedia Commons.
Isopropyl alcohol: structural formula Isopropyl alcohol. This is a ball and stick model. Each sphere is an atom, connected by a single covalent bond. White = hydrogen, black = carbon, and red = oxygen.

Here’s what you need to know about isopropyl alcohol:

  1. Most of isopropyl alcohol (the three carbons and the hydrogens attached to them) is non-polar.
  2. One part of isopropyl alcohol is slightly polar. It’s the oxygen and hydrogen on top. Notice that in the structural formula on the left, the hydrogen (H) has a ?(partial positive charge) next to it, and the oxygen has a ?– (partial negative charge)

So, isopropyl alcohol is slightly polar. But it’s much less polar than water is.

08_water, structural, with delta charges 17_better isopropyl alcohol
Water:highly polar Isopropyl Alcohol: much less polar than water

Knowing that, let’s do a few experiments where we compare them.

3. Six Observations/Experiments Comparing Water and Alcohol

The experiments that follow are hands-on if you can get the materials. But even if you can’t, making predictions about what will happen will vastly increase the amount that you’ll learn. So get out some paper, and, for each observation that follows, write down your answer before clicking “show the answer.” I guarantee that you’ll learn a lot more if you do.

3.1: Comparing Single Drops of Water and Alcohol

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[q]Let’s start by predicting the way that a single drop of water and a single drop of alcohol will look when you put them on a surface like a penny or wax paper. Do the following

  1. In your notes, draw a picture of how you think a single drop of water on a penny will look, compared with how a single drop of alcohol will look.
  2. Below your drawing, explain why you think the two will be different. 
  3. Once you’ve made your drawing and prediction, go ahead and do the experiment if you have materials. Then click “show the answer.”
  4. If you don’t have the materials, click on “show the answer” to see the results and to verify your prediction.

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

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3.2: Piling water and alcohol drops on a penny

[qwiz style = “width: 528px; min-height:0px; border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Virtual lab: Drops on a Penny”]

[q]Use what you just observed to predict the following. How many drops of water can you put onto a penny before the water spills over the side? How many drops of alcohol before the alcohol spills over the side. Make a prediction, give it a try, and, most importantly, explain what’s happening.

When you’re ready, click on “show the answer” to see the results and to verify your prediction.

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

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3.3: Speed of Evaporation in Water and Alcohol

This video compares the evaporation for a drop of alcohol (left) with a drop of water (right). I used my phone as both a surface and a timer (and then speeded up the video about 60 times, so that each minute on the clock goes by in a second).

[qwiz style = “width: 528px; min-height:0px; border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Virtual Lab: Evaporation”]

[q] Explain why the evaporation times for water and alcohol are so different. Note that it takes about 20 hours for a drop of water to evaporate (I didn’t have enough memory in my camera to film this to completion).

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

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3.4: Comparing How Water and Alcohol Feel on Your Skin

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[q] Let’s start by predicting the way that a single drop of water and a single drop of alcohol will feel when you place a few drops of each liquid on your skin. Do the following

  1. In your notes, make a prediction about how each liquid will feel when placed on your skin. Below your prediction, explain why you think the two will be different. 
  2. If you have the materials, place the same number of drops of alcohol and water on different areas of your skin (for example, different parts of the back of your hand). If you can, work with a partner, have your partner place the drops on your hand while your eyes are closed. Without looking, can you tell which drop was which?  Afterwards, click on “show the answer” to see if your results correspond with what I’ve written below.
  3. If you don’t have the materials, just click on “show the answer” to see the results and to verify your prediction.

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

[f]IEFOU1dFUjwvcD4KPHRhYmxlIHN0eWxlPSJoZWlnaHQ6IDIyMXB4OyB3aWR0aDogNTEwcHg7IiBib3JkZXI9IjMiIHdpZHRoPSI1NDkiPgo8dGJvZHk+Cjx0cj4KPHRkPjxzdHJvbmc+SG93IHdhdGVyIGZlZWxzIG9uIHlvdXIgc2tpbjwvc3Ryb25nPjwvdGQ+Cjx0ZD48c3Ryb25nPkhvdyBhbGNvaG9sIGZlZWxzIG9uIHlvdXIgc2tpbjwvc3Ryb25nPjwvdGQ+CjwvdHI+Cjx0cj4KPHRkPk5vdCBhcyBjb29sIGFzIHRoZSBhbGNvaG9sPC90ZD4KPHRkPkNvb2xlciB0aGFuIHRoZSBkcm9wIG9mIHdhdGVyPC90ZD4KPC90cj4KPHRyPgo8dGQgY29sc3Bhbj0iMiI+QXMgeW91IG1pZ2h0IGJlIGV4cGVjdGluZywgdGhlIHJlYXNvbiBmb3IgdGhlIGRpZmZlcmVuY2UgaXMgaHlkcm9nZW4gYm9uZGluZywgYW5kIHdhdGVyJiM4MjE3O3MgbXVjaCBoaWdoZXIgaGVhdCBvZiB2YXBvcml6YXRpb24gdGhhdCBhbGNvaG9sLiBCZWNhdXNlIG9mIGh5ZHJvZ2VuIGJvbmRzLCB0aGUgd2F0ZXIgbW9sZWN1bGVzIGFyZW4mIzgyMTc7dCBldmFwb3JhdGluZy4gVGhhdCBtZWFucyB0aGF0IGFzIHlvdXIgYm9keSBoZWF0IHdhcm1zIHVwIHRoZSB3YXRlciBtb2xlY3VsZXMsIHRoZXkmIzgyMTc7cmUgd2FybWluZyB1cCwgdG9vLiBUaGUgYWxjb2hvbCBtb2xlY3VsZXMsIGJ5IGNvbnRyYXN0LCBhcmVuJiM4MjE3O3QgY29ubmVjdGVkIGJ5IGh5ZHJvZ2VuIGJvbmRzLiBBcyB0aGV5IGFic29yYiBoZWF0IGZyb20geW91ciBza2luLCB0aGV5IHN0YXJ0IHRvIG1vdmUgZmFzdGVyIGFuZCBmYXN0ZXIuIEFzIHRoZXkgc3RhcnQgdG8gZXZhcG9yYXRlLCB0aGV5IGNhcnJ5IHRoZWlyIGhlYXQgZW5lcmd5IGF3YXkgZnJvbSB5b3VyIHNraW4uIFlvdSBwZXJjZWl2ZSB0aGF0IGxvc3Mgb2YgaGVhdCBlbmVyZ3kgYXMgY29vbG5lc3MuPC90ZD4KPC90cj4KPC90Ym9keT4KPC90YWJsZT4K

[x]

[/qwiz]

3.5: Dissolving Salt in Water and Alcohol

[qwiz style = “width: 528px; min-height:0px; border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Virtual Lab: Dissolving Salt”]

[q] Let’s start by predicting the how easily salt will dissolve in water and alcohol.

  1. In your notes, make a prediction about whether or not salt will dissolve in water, and whether or not salt will dissolve in an equal amount of alcohol. 
  2. If you have the materials, use two cups.
    1. place a small amount of water (100 mL) in a cup, and an equal amount of alcohol in a second cup.
    2. Use one teaspoon to put about 1/2 a teaspoon of salt in the water cup. Stir. Record what happens.
    3. Using a second teaspoon, put about 1/2 a teaspoon of salt into the alcohol cup. Stir. Record what happens.
  3. If you don’t have the materials, just click on “show the answer” to see the results and to verify your prediction.

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

[f]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[/qwiz]

3.6: Floating a paper clip on water and alcohol

[qwiz style = “width: 528px; min-height:0px; border: 3px solid black; ” qrecord_id=”sciencemusicvideosMeister1961-Virtual Lab: Paper Clip”]

[q] Here’s a final challenge. See if you can float a paper clip on the surface of a cup of water. Then see if you can do the same with alcohol. Here’s the procedure. If you don’t have the materials, read the procedure anyway, and try to predict what will happen in each case.

  1. Fill a cup with water. To make this easy, use a small cup (but one that’s big enough for a paper clip to float on the surface.
  2. Use a small paper clip. It’s easiest if you bend up a short metal handle from the paper clip so you can place the clip on the water as gently as possible. Bend it like this
  3. Gently place the paper clip on the surface of the water, then let go.
  4. Repeat exactly the same step, except with alcohol in a cup (instead of water)
  5. If you don’t have the materials, just click on “show the answer” to see the results and to verify your prediction.

[c]wqBzaG93IHRo ZSBhbnN3ZXI=

[f]IEFOU1dFUjwvcD4KPHRhYmxlIHN0eWxlPSJoZWlnaHQ6IDIyMXB4OyB3aWR0aDogNTEwcHg7IiBib3JkZXI9IjMiIHdpZHRoPSI1NDkiPgo8dGJvZHk+Cjx0cj4KPHRkIHN0eWxlPSJ0ZXh0LWFsaWduOiBjZW50ZXI7Ij48c3Ryb25nPlBhcGVyIGNsaXA6IGZsb2F0aW5nIG9uIHdhdGVyPC9zdHJvbmc+PC90ZD4KPHRkIHN0eWxlPSJ0ZXh0LWFsaWduOiBjZW50ZXI7Ij48c3Ryb25nPlBhcGVyIGNsaXA6IHN1bmsgaW4gYWxjb2hvbDwvc3Ryb25nPjwvdGQ+CjwvdHI+Cjx0cj4KPHRkPgo8aDM+PGlucHV0IG5hbWU9InF3aXpfaW1nIiBjbGFzcz0id3AtaW1hZ2UtOTY5MiBhbGlnbmxlZnQiIHNyYz0iaHR0cHM6Ly9sZWFybi1iaW9sb2d5LmNvbS93cC1jb250ZW50L3VwbG9hZHMvMjAxNC8wNy8xMl9wYXBlcmNsaXAtb24td2F0ZXIuanBnIiBhbHQ9IjEyX3BhcGVyY2xpcCBvbiB3YXRlciIgd2lkdGg9IjIwMiIgaGVpZ2h0PSIxMjEiIC8+PC9oMz4KPC90ZD4KPHRkPjxpbnB1dCBuYW1lPSJxd2l6X2ltZyIgY2xhc3M9ImFsaWdubm9uZSB3cC1pbWFnZS05NjkzIiBzcmM9Imh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTJhX3BhcGVyY2xpcC1zdW5rLWluLWFsY29ob2wuanBnIiBhbHQ9IjEyYV9wYXBlcmNsaXAgc3VuayBpbiBhbGNvaG9sIiB3aWR0aD0iMjI2IiBoZWlnaHQ9IjEzNyIgLz48L3RkPgo8L3RyPgo8dHI+Cjx0ZCBjb2xzcGFuPSIyIj5TY2llbmNlIGlzIGFsbCBhYm91dCByZXBlYXRhYmxlLCB2ZXJpZmlhYmxlIHJlc3VsdHMuIEkgY2FuJiM4MjE3O3QgZGVmaW5pdGl2ZWx5IHNheSB0aGF0IGEgcGFwZXIgY2xpcCB3aWxsIDxlbT5uZXZlcjwvZW0+IGZsb2F0IG9uIGFsY29ob2wuIEJ1dCBJJiM4MjE3O3ZlIGhhZCBodW5kcmVkcyBvZiBzdHVkZW50cyB0cnkgdGhpcyBvdmVyIHRoZSB5ZWFycywgYW5kIEkmIzgyMTc7dmUgbmV2ZXIgc2VlbiBvbmUgc3VjY2VlZC4gSGVyZSYjODIxNztzIHdoYXQmIzgyMTc7cyBoYXBwZW5pbmcuPC9wPgo8ZmlndXJlIGlkPSJhdHRhY2htZW50Xzk2OTYiIGFyaWEtZGVzY3JpYmVkYnk9ImNhcHRpb24tYXR0YWNobWVudC05Njk2IiBzdHlsZT0id2lkdGg6IDQyNnB4IiBjbGFzcz0id3AtY2FwdGlvbiBhbGlnbm5vbmUiPjxpbnB1dCBuYW1lPSJxd2l6X2ltZyIgY2xhc3M9IndwLWltYWdlLTk2OTYgIiBzcmM9Imh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLnBuZyIgYWx0PSIxNl9jbGlwIG9uIG5ldCBvZiB3YXRlciBtb2xlY3VsZXMiIHdpZHRoPSI0MjYiIGhlaWdodD0iMjA0IiBzcmNzZXQ9Imh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLnBuZyA3NzF3LCBodHRwczovL2xlYXJuLWJpb2xvZ3kuY29tL3dwLWNvbnRlbnQvdXBsb2Fkcy8yMDE0LzA3LzE2X2NsaXAtb24tbmV0LW9mLXdhdGVyLW1vbGVjdWxlcy0xNTB4NzIucG5nIDE1MHcsIGh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLTMwMHgxNDQucG5nIDMwMHcsIGh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLTU2MHgyNjgucG5nIDU2MHcsIGh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLTI2MHgxMjQucG5nIDI2MHcsIGh0dHBzOi8vbGVhcm4tYmlvbG9neS5jb20vd3AtY29udGVudC91cGxvYWRzLzIwMTQvMDcvMTZfY2xpcC1vbi1uZXQtb2Ytd2F0ZXItbW9sZWN1bGVzLTE2MHg3Ny5wbmcgMTYwdyIgc2l6ZXM9IihtYXgtd2lkdGg6IDQyNnB4KSAxMDB2dywgNDI2cHgiIC8+PGZpZ2NhcHRpb24gaWQ9ImNhcHRpb24tYXR0YWNobWVudC05Njk2IiBjbGFzcz0id3AtY2FwdGlvbi10ZXh0Ij5TbyBtYW55IHRoaW5ncyBhcmUgd3Jvbmcgd2l0aCB0aGlzIGltYWdlIChzY2FsZSBpcyBvbmx5IG9uZSksIGJ1dCBJJiM4MjE3O20gdHJ5aW5nIHRvIGNvbnZleSB0aGUgaWRlYSBvZiBhICYjODIyMDtuZXQmIzgyMjE7IG9mIHdhdGVyIG1vbGVjdWxlcywgY29ubmVjdGVkIGJ5IGh5ZHJvZ2VuIGJvbmRzLjwvZmlnY2FwdGlvbj48L2ZpZ3VyZT4KPHA+QmVjYXVzZSB3YXRlciBtb2xlY3VsZXMgYXJlIHBvbGFyLCB0aGV5IGNvbm5lY3QgdGhyb3VnaCBoeWRyb2dlbiBib25kcy4gVGhleSBkbyB0aGlzIGF0IHRoZSBzdXJmYWNlIG9mIHRoZSBib2R5IG9mIHdhdGVyICh3aGVyZSBpdCBjb250YWN0cyB0aGUgYWlyIGFib3ZlIGl0KSwgYXMgd2VsbCBpbnNpZGUgdGhlIGJvZHkgb2Ygd2F0ZXIuIFNvIHRyeSB0byBpbWFnaW5lIHRoYXQgcGFwZXIgY2xpcCBmbG9hdGluZyBvbiBhIHdlYiBvZiB3YXRlciBtb2xlY3VsZXMuIEFzIGxvbmcgYXMgdGhlIGNsaXAgZG9lc24mIzgyMTc7dCBicmVhayB0aGUgd2ViLCBpdCBjYW4gZmxvYXQgb24gdG9wLiBUaGUgbmFtZSBmb3IgdGhpcyB3ZWIgb2Ygd2F0ZXIgbW9sZWN1bGVzIG9uIHRoZSBzdXJmYWNlIG9mIGEgYm9keSBvZiB3YXRlciBpcyA8ZW0+c3VyZmFjZSB0ZW5zaW9uLjwvZW0+PC9wPgo8cD5Ob3QgdGhhdCB0aGlzIGlzIDxlbT5ub3Q8L2VtPiB3aHkgd29vZCwgb3IgYWlyY3JhZnQgY2FycmllcnMsIGZsb2F0IG9uIHdhdGVyLiBUaG9zZSBvYmplY3RzIGFyZSBmbG9hdGluZyBiZWNhdXNlIHRoZWlyIG92ZXJhbGwgZGVuc2l0eSBpcyBsZXNzIHRoYW4gdGhhdCBvZiB3YXRlciAobW9zdGx5IGJlY2F1c2Ugb2YgdHJhcHBlZCBlbXB0eSBzcGFjZSBhbmQgYWlyIGluc2lkZSB0aGUgd29vZCBvciB0aGUgYm9hdCkuIFRoZSBwYXBlciBjbGlwLCBieSBjb250cmFzdCwgaXMgbXVjaCA8ZW0+ZGVuc2VyPC9lbT4gdGhhbiB0aGUgd2F0ZXIuIFRoZSBmbG9hdGluZyB0aGF0IHlvdSBvYnNlcnZlIGluIHRoZSBwYXBlciBjbGlwIGlzIGNhdXNlZCBieSBzdXJmYWNlIHRlbnNpb24sIDxlbT5ub3Q8L2VtPiBieSBkZW5zaXR5LjwvcD4KPHA+QWxjb2hvbCBpcyBtdWNoIGxlc3MgcG9sYXIgdGhhbiB3YXRlci4gQmVjYXVzZSBpdCYjODIxNztzIG5vbi1wb2xhciwgdGhlIG1vbGVjdWxlcyBkb24mIzgyMTc7dCBmb3JtIGh5ZHJvZ2VuIGJvbmRzLiBCZWNhdXNlIHRoZXkgZG9uJiM4MjE3O3QgZm9ybSBoeWRyb2dlbiBib25kcywgdGhlIGNsaXBzIHNpbmsgdGhyb3VnaCB0aGUgc3VyZmFjZS4gRXNzZW50aWFsbHksIGluIHRoZSBhbGNvaG9sIHNvbHV0aW9uLCB0aGVyZSYjODIxNztzIG5vIHN1cmZhY2UgdGVuc2lvbiAob3IsIGF0IGxlYXN0LCBub3QgbmVhcmx5IGVub3VnaCB0byBzdXBwb3J0IGEgcGFwZXIgY2xpcCkuPC90ZD4KPC90cj4KPC90Ym9keT4KPC90YWJsZT4K

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4. Summary: Five properties of water that you should remember

Everything you observed in this lab resulted from water’s polarity. Here are the specific properties of water that you should remember from this lab and video.

  1. Because of hydrogen bonding, water molecules stick to one another. This is a property known as cohesion. We saw this in the shape of a water molecule compared to an alcohol molecule. And we saw this in our demonstration of surface tension. As you’ll see later in this course, cohesion among water molecules explains how 300 foot tall redwood trees can transport water up the length of their trunk. It’s all about each water molecule tugging on the one behind it, all the way up to the top of the tree.
  2. Water is a great solvent of ionic and polar substances.
  3. Water has a very high heat of vaporization, which means that it takes a lot of energy to change water from a liquid to a gas. That’s why it takes water so much longer to evaporate than alcohol. Also, when water does evaporate, it removes a lot of heat from the object that it’s evaporating from. This is why perspiration is such an effective way to cool us down. As that water on our skin evaporates, the overall temperature of our bodies is decreased.
  4. Water has a relatively high freezing point. That’s because when water molecules get cool enough, they’ll grab onto one another through hydrogen bonding. Liquids such as alcohol, which don’t form hydrogen bonds, have to be cooled much more before they’ll form inter-molecular bonds and become solid.
  5. Water is less dense as a solid than as a liquid. As a result, ice floats on water. This is because when water freezes, the hydrogen bonds generate a crystal matrix in which the molecules are more spread out than when water is in a liquid form. This is an absolutely unique property: water might be the only substance whose solid form is less dense than its liquid form.

    ice
    Source: http://www.computational-chemistry.co.uk/odyssey/gallery_files/ice.gif. Permission pending.

 5. Checking Understanding: Properties of Water

[qwiz random = “true” qrecord_id=”sciencemusicvideosMeister1961-Properties of Water Virtual Lab Quiz (M4)”]

[h]Properties of Water Quiz

[i]This quiz is a combination of the game “hangman” and a flashcard deck. With each question, you’ll type in the answer. If you get the question wrong, it goes back in the deck for you to repeat it.

[q] Water is

[hangman]

[c]cG9sYXI=

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[q]Water forms _________ bonds

[hangman]

[c]aHlkcm9nZW4=

[f]WWVzLiBXYXRlciBmb3JtcyBoeWRyb2dlbiBib25kczwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz4=

[q]The ______ side of water has a partial positive charge

[hangman]

[c]aHlkcm9nZW4=

[f]Q29ycmVjdC7CoFRoZSA8dT5oeWRyb2dlbjwvdT4gc2lkZSBvZiB3YXRlciBoYXMgYSBwYXJ0aWFsIHBvc2l0aXZlIGNoYXJnZTwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz4=

[q]The hydrogen side of water has a partial ________ charge

[hangman]

[c]cG9zaXRpdmU=

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[q]The _______ side of water has a partial negative charge

[hangman]

[c]b3h5Z2Vu

[f]WWVzLlRoZSA8dT5veHlnZW48L3U+IHNpZGUgb2Ygd2F0ZXIgaGFzIGEgcGFydGlhbCBuZWdhdGl2ZSBjaGFyZ2U8L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]The oxygen side of water has a partial ______ charge

[hangman]

[c]bmVnYXRpdmU=

[f]WWVzLlRoZSBveHlnZW4gc2lkZSBvZiB3YXRlciBoYXMgYSBwYXJ0aWFsIDx1Pm5lZ2F0aXZlPC91PiBjaGFyZ2U8L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because of _______ bonding, water molecules have a lot of cohesion.

[hangman]

[c]aHlkcm9nZW4=

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[q]Because of hydrogen bonding, water molecules have a lot of _______.

[hangman]

[c]Y29oZXNpb24=

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[q]Isopropyl alcohol is much less _______ than water is.

[hangman]

[c]cG9sYXI=

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[q]Because it has less hydrogen bonding, a drop of alcohol will have a much _______ shape than a drop of water.

[hangman]

[c]RmxhdHRlcg==

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[q]Because it has less _________ bonding, a drop of alcohol will have a much flatter shape than a drop of water.

[hangman]

[c]aHlkcm9nZW4=

[f]TmljZSBqb2IuQmVjYXVzZSBpdCBoYXMgbGVzcyA8dT5oeWRyb2dlbjwvdT4gYm9uZGluZywgYcKgZHJvcCBvZiBhbGNvaG9sIHdpbGwgaGF2ZSBhIG11Y2ggZmxhdHRlcsKgc2hhcGUgdGhhbiBhIGRyb3Agb2Ygd2F0ZXIuPC9wPgo8cD48c3Ryb25nPjwvc3Ryb25nPg==

[q]The amount of heat required to make a liquid into a gas is its heat of ___________.

[hangman]

[c]dmFwb3JpemF0aW9u

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[q]The amount of _____ required to make a liquid into a gas is its heat of vaporization.

[hangman]

[c]aGVhdA==

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[q]The amount of heat required to make a liquid into a ___ is its heat of vaporization.

[hangman]

[c]Z2Fz

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[q]Alcohol has a much lower heat of _________ than water.

[hangman]

[c]dmFwb3JpemF0aW9u

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[q]Alcohol has a much ______ heat of vaporization than water.

[hangman]

[c]bG93ZXI=

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[q]Because of _______ bonding, water molecules have a very high heat of vaporization.

[hangman]

[c]aHlkcm9nZW4=

[f]QXdlc29tZS7CoEJlY2F1c2Ugb2YgPHU+aHlkcm9nZW48L3U+wqBib25kaW5nLCB3YXRlciBtb2xlY3VsZXMgaGF2ZSBhIHZlcnkgaGlnaCBoZWF0IG9mIHZhcG9yaXphdGlvbi48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because of hydrogen bonding, water molecules have a very high heat of _______.

[hangman]

[c]dmFwb3JpemF0aW9u

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[q]Because of hydrogen bonding, water molecules have a very high heat of ___________.

[hangman]

[c]dmFwb3JpemF0aW9u

[f]QXdlc29tZS7CoEF3ZXNvbWUuwqBCZWNhdXNlIG9mIGh5ZHJvZ2VuwqBib25kaW5nLCB3YXRlciBtb2xlY3VsZXMgaGF2ZSBhIHZlcnkgPHU+aGlnaDwvdT4gaGVhdCBvZiB2YXBvcml6YXRpb24uPC9wPgo8cD48c3Ryb25nPjwvc3Ryb25nPg==

[q]Because water is polar, it’s great at dissolving ________ substances like salt.

[hangman]

[c]aW9uaWM=

[f]WWVzLkJlY2F1c2Ugd2F0ZXIgaXMgcG9sYXIsIGl04oCZcyBncmVhdCBhdCBkaXNzb2x2aW5nIDx1PmlvbmljPC91PiBzdWJzdGFuY2VzIGxpa2Ugc2FsdC48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because water is ______, it’s great at dissolving ionic substances like salt.

[hangman]

[c]cG9sYXI=

[f]WWVzLkJlY2F1c2Ugd2F0ZXIgaXMgcG9sYXIsIGl04oCZcyBncmVhdCBhdCBkaXNzb2x2aW5nIGlvbmljIHN1YnN0YW5jZXMgbGlrZSBzYWx0LjwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz4=

[q]Because water is polar, it’s great at dissolving ionic substances, and  just about any _______ substance.

[hangman]

[c]cG9sYXI=

[f]TmljZSBqb2IuwqBCZWNhdXNlIHdhdGVyIGlzIHBvbGFyLCBpdOKAmXMgZ3JlYXQgYXQgZGlzc29sdmluZyBpb25pYyBzdWJzdGFuY2VzLCBhbmQganVzdCBhYm91dCBhbnkgX19fX19fX8Kgc3Vic3RhbmNlLjwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz4=

[q]Because of hydrogen bonding, water has a lot of surface ________, enabling a paper clip to float on the surface of a body of water.

[hangman]

[c]dGVuc2lvbg==

[f]R29vZCB3b3JrLsKgQmVjYXVzZSBvZiBoeWRyb2dlbiBib25kaW5nLCB3YXRlciBoYXMgYSBsb3Qgb2Ygc3VyZmFjZSA8dT50ZW5zaW9uPC91PiwgZW5hYmxpbmcgYSBwYXBlciBjbGlwIHRvIGZsb2F0IG9uIHRoZSBzdXJmYWNlIG9mIGEgYm9keSBvZiB3YXRlci48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because of ________ bonding, water has a lot of surface tension, enabling a paper clip to float on the surface of a body of water.

[hangman]

[c]aHlkcm9nZW4=

[f]R29vZCB3b3JrLsKgQmVjYXVzZSBvZiA8dT5oeWRyb2dlbjwvdT4gYm9uZGluZywgd2F0ZXIgaGFzIGEgbG90IG9mIHN1cmZhY2UgdGVuc2lvbiwgZW5hYmxpbmcgYSBwYXBlciBjbGlwIHRvIGZsb2F0IG9uIHRoZSBzdXJmYWNlIG9mIGEgYm9keSBvZiB3YXRlci48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because of hydrogen bonding, water has a lot of surface tension, enabling a paper clip to ______ on the surface of a body of water.

[hangman]

[c]ZmxvYXQ=

[f]R29vZCB3b3JrLsKgQmVjYXVzZSBvZiBoeWRyb2dlbiBib25kaW5nLCB3YXRlciBoYXMgYSBsb3Qgb2Ygc3VyZmFjZSB0ZW5zaW9uLCBlbmFibGluZyBhIHBhcGVyIGNsaXAgdG8gZmxvYXQgb24gdGhlIHN1cmZhY2Ugb2YgYSBib2R5IG9mIHdhdGVyLjwvcD4KPHA+PHN0cm9uZz48L3N0cm9uZz4=

[q]In order for water to evaporate, _________ bonds need to be broken.

[hangman]

[c]aHlkcm9nZW4=

[f]Q29ycmVjdC7CoEluIG9yZGVyIGZvciB3YXRlciB0byBldmFwb3JhdGUsIDx1Pmh5ZHJvZ2VuPC91PiBib25kcyBuZWVkIHRvIGJlIGJyb2tlbi48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]In order for water to evaporate, hydrogen bonds need to be ________.

[hangman]

[c]YnJva2Vu

[f]Q29ycmVjdC7CoENvcnJlY3QuwqBJbiBvcmRlciBmb3Igd2F0ZXIgdG8gZXZhcG9yYXRlLCBoeWRyb2dlbiBib25kcyBuZWVkIHRvIGJlIDx1PmJyb2tlbjwvdT4uPC9wPgo8cD48c3Ryb25nPjwvc3Ryb25nPg==

[q]In order for water to _________, hydrogen bonds need to be broken.

[hangman]

[c]ZXZhcG9yYXRl

[f]Q29ycmVjdC7CoEluIG9yZGVyIGZvciB3YXRlciB0byA8dT5ldmFwb3JhdGU8L3U+LCBoeWRyb2dlbiBib25kcyBuZWVkIHRvIGJlIGJyb2tlbi48L3A+CjxwPjxzdHJvbmc+PC9zdHJvbmc+

[q]Because of hydrogen bonding, water freezes at a relatively _____ temperature.

[hangman]

[c]aGlnaA==

[f]TmljZS7CoEJlY2F1c2Ugb2YgaHlkcm9nZW4gYm9uZGluZywgd2F0ZXIgZnJlZXplcyBhdCBhIHJlbGF0aXZlbHkgPHU+aGlnaDwvdT4gdGVtcGVyYXR1cmUuPC9wPgo8cD48c3Ryb25nPjwvc3Ryb25nPg==

[q]Because of ________ bonding, water freezes at a relatively high temperature.

[hangman]

[c]aHlkcm9nZW4=

[f]TmljZS7CoEJlY2F1c2Ugb2YgPHU+aHlkcm9nZW48L3U+IGJvbmRpbmcsIHdhdGVyIGZyZWV6ZXMgYXQgYSByZWxhdGl2ZWx5IGhpZ2ggdGVtcGVyYXR1cmUuPC9wPgo8cD48c3Ryb25nPjwvc3Ryb25nPg==

[q]Because of hydrogen bonding, ice is less ______ than liquid water.

[hangman]

[c]ZGVuc2U=

[f]WWVzLsKgQmVjYXVzZSBvZiBoeWRyb2dlbiBib25kaW5nLCBpY2UgaXMgbGVzcyA8dT5kZW5zZTwvdT4gdGhhbiBsaXF1aWQgd2F0ZXIu

[x][restart]

[/qwiz]

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