3. Water

Properties of Water- Thermal

Properties of Water: How Does a Temperature Affect Water Molecules?

 Changing the temperature of 1 g of water from 10&#176;C to 90&#176;C 

 No. This would require only 80 calories. 

 Cooling 10 g of water from 80&#176;C to 40&#176;C 

 No. Evaporating 1 g of water requires about 580 calories. 

 Condensing 5 g of steam to liquid water 

Remember that heat takes into account the amount of a substance. You may need to do some multiplication to get to the answer.

Which action would involve the greatest transfer of heat?

Importance of water for life | Chemistry of life | AP Biology | Khan Academy

Properties of Water

 No. This answer applies specifically to water and is the amount of energy it takes to raise the temperature of 1 g of water by 1&#176;C. 

 the heat of vaporization of that substance 

 No. This is the amount of energy required to convert 1 g of a liquid to the gaseous state. 

 No. This answer applies specifically to water and is the amount of energy it takes to raise the temperature of 1,000 g of water by 1&#176;C. 

Think about how well a substance resists changing its temperature when it absorbs or releases heat.

The amount of heat required to change the temperature of 1 g of any substance by 1&#176;C is defined as __________.

 No. Water has a high specific heat but not as high as ammonia's. 

 No. Water has a high heat of vaporization relative to most other liquids. 

 a lower capacity for forming hydrogen bonds 

 No. Water is a polar molecule and thus has a high capacity for forming hydrogen bonds. 

This is an emergent property of water.

Water has __________ than other liquids such as ethanol, reflecting its capacity to absorb large amounts of heat.

 If water molecules were nonpolar, then water vapor would be less effective as a greenhouse gas, and the effects of global warming would be less extreme. 

 No. Water vapor's role as a greenhouse gas is not related to the polar nature of the molecule. 

 The effects would be worse because a loss of the polar molecular structure would lead to a greater amount of heat absorbed by water molecules and, thus, an increase in its specific heat. 

 No. The loss of the polar nature of water would greatly lower its specific heat and so reduce the ability of water to moderate temperature. 

 If water were nonpolar, the effects on global warming would be only slightly worse because there are other polar molecules that can moderate climate as water does. 

 No. There are other polar molecules with high specific heats, but they don't occur naturally in sufficient quantities to moderate global warming. 

 The effects would be drastically worse because the loss of the polar nature of water would greatly reduce its specific heat and its ability to moderate temperature. 

Consider the emergent properties of water related to heat.

If water were not a polar molecule, how would the effects of climatic warming differ from those currently observed or predicted to occur in the future?

A lake heats up more slowly than the surrounding environment.

Sugar dissolves in hot tea faster than in iced tea.

Which of the following is due to the high specific heat of water?a) Oil does not mix with water.b) A lake heats up more slowly than the surrounding environment.c) The high surface tension of water.d) Sugar dissolves in hot tea faster than in iced tea.

Water’s High Specific Heat

Heat Capacity of Water

 No. The specific heat of a substance is defined as the amount of heat required to change the temperature of 1 g of that substance by 1&#176;C. 

 No. This applies specifically to water and is the amount of energy it takes to raise the temperature of 1 g of water by1&#176;C. 

 No. Surface tension is a measure of how difficult it is to break the surface of a liquid; it is not an amount of energy. 

What does it take to evaporate a substance?

The amount of heat required to convert 1 g of any substance from the liquid to the gaseous state is defined as __________.

Which if the following defines the term evaporation?a) The conversion of a liquid into a vapor.b) The conversion of a solid into a vapor.c) The conversion of a vapor into a liquid.d) The conversion of a vapor into a solid.

Water has a high heat-absorbing capacity because                   .
a. the sun’s rays penetrate to the bottom of bodies of water, mainly heating the bottom surface;
b. the strong covalent bonds that hold individual water molecules together require large inputs of heat to break;
c. it has the ability to dissolve many heat-resistant solutes;
d. initial energy inputs are first used to break hydrogen bonds between water molecules and only after these are broken, to raise the temperature;
e. all of the above are true

Has a lower specific heat than most other molecules.

Has a higher heat of vaporization than most other molecules.

Choose the correct statement: Liquid water ________.a) Is less dense than ice.b) Has a lower specific heat than most other molecules.c) Has a higher heat of vaporization than most other molecules.d) Is nonpolar.

Water - Liquid Awesome: Crash Course Biology #2

 No. Surface tension is a measure of how difficult it is to break the surface of a liquid. 

 No. Adhesion refers to the tendency of one substance to cling to another. 

 No. Heat of vaporization is the quantity of heat required to convert 1 g of a liquid to the gaseous state. 

Consider which of these refers to the amount of heat that must be absorbed or lost for a substance to change temperature.

The reason that coastal climates are more moderate than inland climates primarily water's high __________.

A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.)
a. 50°C
b. 5°C
c. 100°C
d. 10°C

Water Is WAY Weirder Than We Thought

 Organisms would be able to live in a much wider range of temperatures. 

 No. The high specific heat of water helps organisms resist changes in temperature, enabling them to live in a fairly wide range of temperature conditions. Fluids with a lower specific heat would restrict habitable temperature ranges. 

 Living organisms would have to be much smaller. 

 No. The opposite would probably be true. Larger size leads to a decrease in the ratio of surface area to volume, which would help conserve heat. 

 Warm-blooded organisms would require less insulation such as fur or feathers. 

 No. The opposite would be true. Temperature regulation systems such as insulation would need to be more efficient in order to make up for the low specific heat of alcohol. 

 Systems for temperature regulation would have to be much more efficient. 

How does an organism's specific heat affect the organism’s ability to regulate its temperature?

Imagine that organisms consisted of 70&ndash;95% alcohol instead of 70&ndash;95% water. Alcohol's specific heat is about half that of water. How would living things be different?

 No. Buffers resist changes in pH but do not have an effect on water's cooling capacity. 

Why does evaporation of sweat cool the surface of the skin?

Sweating has a cooling effect because of water's high __________.

Apply Darwin’s four postulates to a population of mice living on sand dunes in coastal Florida.

Water’s High Heat of Vaporization

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